Posts Tagged API

Istio Observability with Go, gRPC, and Protocol Buffers-based Microservices

In the last two posts, Kubernetes-based Microservice Observability with Istio Service Mesh and Azure Kubernetes Service (AKS) Observability with Istio Service Mesh, we explored the observability tools which are included with Istio Service Mesh. These tools currently include Prometheus and Grafana for metric collection, monitoring, and alerting, Jaeger for distributed tracing, and Kiali for Istio service-mesh-based microservice visualization and monitoring. Combined with cloud platform-native monitoring and logging services, such as Stackdriver on GCP, CloudWatch on AWS, Azure Monitor logs on Azure, and we have a complete observability solution for modern, distributed, Cloud-based applications.

In this post, we will examine the use of Istio’s observability tools to monitor Go-based microservices that use Protocol Buffers (aka Protobuf) over gRPC (gRPC Remote Procedure Calls) and HTTP/2 for client-server communications, as opposed to the more traditional, REST-based JSON (JavaScript Object Notation) over HTTP (Hypertext Transfer Protocol). We will see how Kubernetes, Istio, Envoy, and the observability tools work seamlessly with gRPC, just as they do with JSON over HTTP, on Google Kubernetes Engine (GKE).



Image result for grpc logogRPC

According to the gRPC project, gRPC, a CNCF incubating project, is a modern, high-performance, open-source and universal remote procedure call (RPC) framework that can run anywhere. It enables client and server applications to communicate transparently and makes it easier to build connected systems. Google, the original developer of gRPC, has used the underlying technologies and concepts in gRPC for years. The current implementation is used in several Google cloud products and Google externally facing APIs. It is also being used by Square, Netflix, CoreOS, Docker, CockroachDB, Cisco, Juniper Networks and many other organizations.

Image result for google developerProtocol Buffers

By default, gRPC uses Protocol Buffers. According to Google, Protocol Buffers (aka Protobuf) are a language- and platform-neutral, efficient, extensible, automated mechanism for serializing structured data for use in communications protocols, data storage, and more. Protocol Buffers are 3 to 10 times smaller and 20 to 100 times faster than XML. Once you have defined your messages, you run the protocol buffer compiler for your application’s language on your .proto file to generate data access classes.

Protocol Buffers are 3 to 10 times smaller and 20 to 100 times faster than XML.

Protocol buffers currently support generated code in Java, Python, Objective-C, and C++, Dart, Go, Ruby, and C#. For this post, we have compiled for Go. You can read more about the binary wire format of Protobuf on Google’s Developers Portal.

Image result for envoy proxyEnvoy Proxy

According to the Istio project, Istio uses an extended version of the Envoy proxy. Envoy is deployed as a sidecar to a relevant service in the same Kubernetes pod. Envoy, created by Lyft, is a high-performance proxy developed in C++ to mediate all inbound and outbound traffic for all services in the service mesh. Istio leverages Envoy’s many built-in features, including dynamic service discovery, load balancing, TLS termination, HTTP/2 and gRPC proxies, circuit-breakers, health checks, staged rollouts, fault injection, and rich metrics.

According to the post by Harvey Tuch of Google, Evolving a Protocol Buffer canonical API, Envoy proxy adopted Protocol Buffers, specifically proto3, as the canonical specification of for version 2 of Lyft’s gRPC-first API.

Reference Microservices Platform

In the last two posts, we explored Istio’s observability tools, using a RESTful microservices-based API platform written in Go and using JSON over HTTP for service to service communications. The API platform was comprised of eight Go-based microservices and one sample Angular 7, TypeScript-based front-end web client. The various services are dependent on MongoDB, and RabbitMQ for event queue-based communications. Below, the is JSON over HTTP-based platform architecture.

Golang Service Diagram with Proxy v2

Below, the current Angular 7-based web client interface.


Converting to gRPC and Protocol Buffers

For this post, I have modified the eight Go microservices to use gRPC and Protocol Buffers, Google’s data interchange format. Specifically, the services use version 3 release (aka proto3) of Protocol Buffers. With gRPC, a gRPC client calls a gRPC server. Some of the platform’s services are gRPC servers, others are gRPC clients, while some act as both client and server, such as Service A, B, and E. The revised architecture is shown below.


gRPC Gateway

Assuming for the sake of this demonstration, that most consumers of the API would still expect to communicate using a RESTful JSON over HTTP API, I have added a gRPC Gateway reverse proxy to the platform. The gRPC Gateway is a gRPC to JSON reverse proxy, a common architectural pattern, which proxies communications between the JSON over HTTP-based clients and the gRPC-based microservices. A diagram from the grpc-gateway GitHub project site effectively demonstrates how the reverse proxy works.


Image courtesy:

In the revised platform architecture diagram above, note the addition of the reverse proxy, which replaces Service A at the edge of the API. The proxy sits between the Angular-based Web UI and Service A. Also, note the communication method between services is now Protobuf over gRPC instead of JSON over HTTP. The use of Envoy Proxy (via Istio) is unchanged, as is the MongoDB Atlas-based databases and CloudAMQP RabbitMQ-based queue, which are still external to the Kubernetes cluster.

Alternatives to gRPC Gateway

As an alternative to the gRPC Gateway reverse proxy, we could convert the TypeScript-based Angular UI client to gRPC and Protocol Buffers, and continue to communicate directly with Service A as the edge service. However, this would limit other consumers of the API to rely on gRPC as opposed to JSON over HTTP, unless we also chose to expose two different endpoints, gRPC, and JSON over HTTP, another common pattern.


In this post’s demonstration, we will repeat the exact same installation process, outlined in the previous post, Kubernetes-based Microservice Observability with Istio Service Mesh. We will deploy the revised gRPC-based platform to GKE on GCP. You could just as easily follow Azure Kubernetes Service (AKS) Observability with Istio Service Mesh, and deploy the platform to AKS.

Source Code

All source code for this post is available on GitHub, contained in three projects. The Go-based microservices source code, all Kubernetes resources, and all deployment scripts are located in the k8s-istio-observe-backend project repository, in the new grpc branch.

git clone \
  --branch grpc --single-branch --depth 1 --no-tags \

The Angular-based web client source code is located in the k8s-istio-observe-frontend repository on the new grpc branch. The source protocol buffers .proto file and the generated code, using the protocol buffers compiler, is located in the new pb-greeting project repository. You do not need to clone either of these projects for this post’s demonstration.

All Docker images for the services, UI, and the reverse proxy are located on Docker Hub.

Code Changes

This post is not specifically about writing Go for gRPC and Protobuf. However, to better understand the observability requirements and capabilities of these technologies, compared to JSON over HTTP, it is helpful to review some of the source code.

Service A

First, compare the source code for Service A, shown below, to the original code in the previous post. The service’s code is almost completely re-written. I relied on several references for writing the code, including, Tracing gRPC with Istio, written by Neeraj Poddar of Aspen Mesh and Distributed Tracing Infrastructure with Jaeger on Kubernetes, by Masroor Hasan.

Specifically, note the following code changes to Service A:

  • Import of the pb-greeting protobuf package;
  • Local Greeting struct replaced with pb.Greeting struct;
  • All services are now hosted on port 50051;
  • The HTTP server and all API resource handler functions are removed;
  • Headers, used for distributed tracing with Jaeger, have moved from HTTP request object to metadata passed in the gRPC context object;
  • Service A is coded as a gRPC server, which is called by the gRPC Gateway reverse proxy (gRPC client) via the Greeting function;
  • The primary PingHandler function, which returns the service’s Greeting, is replaced by the pb-greeting protobuf package’s Greeting function;
  • Service A is coded as a gRPC client, calling both Service B and Service C using the CallGrpcService function;
  • CORS handling is offloaded to Istio;
  • Logging methods are unchanged;

Source code for revised gRPC-based Service A (gist):

Greeting Protocol Buffers

Shown below is the greeting source protocol buffers .proto file. The greeting response struct, originally defined in the services, remains largely unchanged (gist). The UI client responses will look identical.

When compiled with protoc,  the Go-based protocol compiler plugin, the original 27 lines of source code swells to almost 270 lines of generated data access classes that are easier to use programmatically.

# Generate gRPC stub (.pb.go)
protoc -I /usr/local/include -I. \
  -I ${GOPATH}/src \
  -I ${GOPATH}/src/ \
  --go_out=plugins=grpc:. \

# Generate reverse-proxy (
protoc -I /usr/local/include -I. \
  -I ${GOPATH}/src \
  -I ${GOPATH}/src/ \
  --grpc-gateway_out=logtostderr=true:. \

# Generate swagger definitions (.swagger.json)
protoc -I /usr/local/include -I. \
  -I ${GOPATH}/src \
  -I ${GOPATH}/src/ \
  --swagger_out=logtostderr=true:. \

Below is a small snippet of that compiled code, for reference. The compiled code is included in the pb-greeting project on GitHub and imported into each microservice and the reverse proxy (gist). We also compile a separate version for the reverse proxy to implement.

Using Swagger, we can view the greeting protocol buffers’ single RESTful API resource, exposed with an HTTP GET method. I use the Docker-based version of Swagger UI for viewing protoc generated swagger definitions.

docker run -p 8080:8080 -d --name swagger-ui \
  -e SWAGGER_JSON=/tmp/greeting.swagger.json \
  -v ${GOAPTH}/src/pb-greeting:/tmp swaggerapi/swagger-ui

The Angular UI makes an HTTP GET request to the /api/v1/greeting resource, which is transformed to gRPC and proxied to Service A, where it is handled by the Greeting function.


gRPC Gateway Reverse Proxy

As explained earlier, the gRPC Gateway reverse proxy service is completely new. Specifically, note the following code features in the gist below:

  • Import of the pb-greeting protobuf package;
  • The proxy is hosted on port 80;
  • Request headers, used for distributed tracing with Jaeger, are collected from the incoming HTTP request and passed to Service A in the gRPC context;
  • The proxy is coded as a gRPC client, which calls Service A;
  • Logging is largely unchanged;

The source code for the Reverse Proxy (gist):

Below, in the Stackdriver logs, we see an example of a set of HTTP request headers in the JSON payload, which are propagated upstream to gRPC-based Go services from the gRPC Gateway’s reverse proxy. Header propagation ensures the request produces a complete distributed trace across the complete service call chain.


Istio VirtualService and CORS

According to feedback in the project’s GitHub Issues, the gRPC Gateway does not directly support Cross-Origin Resource Sharing (CORS) policy. In my own experience, the gRPC Gateway cannot handle OPTIONS HTTP method requests, which must be issued by the Angular 7 web UI. Therefore, I have offloaded CORS responsibility to Istio, using the VirtualService resource’s CorsPolicy configuration. This makes CORS much easier to manage than coding CORS configuration into service code (gist):

Set-up and Installation

To deploy the microservices platform to GKE, follow the detailed instructions in part one of the post, Kubernetes-based Microservice Observability with Istio Service Mesh: Part 1, or Azure Kubernetes Service (AKS) Observability with Istio Service Mesh for AKS.

  1. Create the external MongoDB Atlas database and CloudAMQP RabbitMQ clusters;
  2. Modify the Kubernetes resource files and bash scripts for your own environments;
  3. Create the managed GKE or AKS cluster on GCP or Azure;
  4. Configure and deploy Istio to the managed Kubernetes cluster, using Helm;
  5. Create DNS records for the platform’s exposed resources;
  6. Deploy the Go-based microservices, gRPC Gateway reverse proxy, Angular UI, and associated resources to Kubernetes cluster;
  7. Test and troubleshoot the platform deployment;
  8. Observe the results;

The Three Pillars

As introduced in the first post, logs, metrics, and traces are often known as the three pillars of observability. These are the external outputs of the system, which we may observe. As modern distributed systems grow ever more complex, the ability to observe those systems demands equally modern tooling that was designed with this level of complexity in mind. Traditional logging and monitoring systems often struggle with today’s hybrid and multi-cloud, polyglot language-based, event-driven, container-based and serverless, infinitely-scalable, ephemeral-compute platforms.

Tools like Istio Service Mesh attempt to solve the observability challenge by offering native integrations with several best-of-breed, open-source telemetry tools. Istio’s integrations include Jaeger for distributed tracing, Kiali for Istio service mesh-based microservice visualization and monitoring, and Prometheus and Grafana for metric collection, monitoring, and alerting. Combined with cloud platform-native monitoring and logging services, such as Stackdriver for GKE, CloudWatch for Amazon’s EKS, or Azure Monitor logs for AKS, and we have a complete observability solution for modern, distributed, Cloud-based applications.

Pillar 1: Logging

Moving from JSON over HTTP to gRPC does not require any changes to the logging configuration of the Go-based service code or Kubernetes resources.

Stackdriver with Logrus

As detailed in part two of the last post, Kubernetes-based Microservice Observability with Istio Service Mesh, our logging strategy for the eight Go-based microservices and the reverse proxy continues to be the use of Logrus, the popular structured logger for Go, and Banzai Cloud’s logrus-runtime-formatter.

If you recall, the Banzai formatter automatically tags log messages with runtime/stack information, including function name and line number; extremely helpful when troubleshooting. We are also using Logrus’ JSON formatter. Below, in the Stackdriver console, note how each log entry below has the JSON payload contained within the message with the log level, function name, lines on which the log entry originated, and the message.


Below, we see the details of a specific log entry’s JSON payload. In this case, we can see the request headers propagated from the downstream service.


Pillar 2: Metrics

Moving from JSON over HTTP to gRPC does not require any changes to the metrics configuration of the Go-based service code or Kubernetes resources.


Prometheus is a completely open source and community-driven systems monitoring and alerting toolkit originally built at SoundCloud, circa 2012. Interestingly, Prometheus joined the Cloud Native Computing Foundation (CNCF) in 2016 as the second hosted-project, after Kubernetes.



Grafana describes itself as the leading open source software for time series analytics. According to Grafana Labs, Grafana allows you to query, visualize, alert on, and understand your metrics no matter where they are stored. You can easily create, explore, and share visually-rich, data-driven dashboards. Grafana allows users to visually define alert rules for your most important metrics. Grafana will continuously evaluate rules and can send notifications.

According to Istio, the Grafana add-on is a pre-configured instance of Grafana. The Grafana Docker base image has been modified to start with both a Prometheus data source and the Istio Dashboard installed. Below, we see two of the pre-configured dashboards, the Istio Mesh Dashboard and the Istio Performance Dashboard.



Pillar 3: Traces

Moving from JSON over HTTP to gRPC did require a complete re-write of the tracing logic in the service code. In fact, I spent the majority of my time ensuring the correct headers were propagated from the Istio Ingress Gateway to the gRPC Gateway reverse proxy, to Service A in the gRPC context, and upstream to all the dependent, gRPC-based services. I am sure there are a number of optimization in my current code, regarding the correct handling of traces and how this information is propagated across the service call stack.


According to their website, Jaeger, inspired by Dapper and OpenZipkin, is a distributed tracing system released as open source by Uber Technologies. It is used for monitoring and troubleshooting microservices-based distributed systems, including distributed context propagation, distributed transaction monitoring, root cause analysis, service dependency analysis, and performance and latency optimization. The Jaeger website contains an excellent overview of Jaeger’s architecture and general tracing-related terminology.

Below we see the Jaeger UI Traces View. In it, we see a series of traces generated by hey, a modern load generator and benchmarking tool, and a worthy replacement for Apache Bench (ab). Unlike abhey supports HTTP/2. The use of hey was detailed in the previous post.


A trace, as you might recall, is an execution path through the system and can be thought of as a directed acyclic graph (DAG) of spans. If you have worked with systems like Apache Spark, you are probably already familiar with DAGs.


Below we see the Jaeger UI Trace Detail View. The example trace contains 16 spans, which encompasses nine components – seven of the eight Go-based services, the reverse proxy, and the Istio Ingress Gateway. The trace and the spans each have timings. The root span in the trace is the Istio Ingress Gateway. In this demo, traces do not span the RabbitMQ message queues. This means you would not see a trace which includes the decoupled, message-based communications between Service D to Service F, via the RabbitMQ.


Within the Jaeger UI Trace Detail View, you also have the ability to drill into a single span, which contains additional metadata. Metadata includes the URL being called, HTTP method, response status, and several other headers.


Microservice Observability

Moving from JSON over HTTP to gRPC does not require any changes to the Kiali configuration of the Go-based service code or Kubernetes resources.


According to their website, Kiali provides answers to the questions: What are the microservices in my Istio service mesh, and how are they connected? Kiali works with Istio, in OpenShift or Kubernetes, to visualize the service mesh topology, to provide visibility into features like circuit breakers, request rates and more. It offers insights about the mesh components at different levels, from abstract Applications to Services and Workloads.

The Graph View in the Kiali UI is a visual representation of the components running in the Istio service mesh. Below, filtering on the cluster’s dev Namespace, we should observe that Kiali has mapped all components in the platform, along with rich metadata, such as their version and communication protocols.


Using Kiali, we can confirm our service-to-service IPC protocol is now gRPC instead of the previous HTTP.



Although converting from JSON over HTTP to protocol buffers with gRPC required major code changes to the services, it did not impact the high-level observability we have of those services using the tools provided by Istio, including Prometheus, Grafana, Jaeger, and Kiali.

All opinions expressed in this post are my own and not necessarily the views of my current or past employers or their clients.


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Istio End-User Authentication for Kubernetes using JSON Web Tokens (JWT) and Auth0

In the recent post, Building a Microservices Platform with Confluent Cloud, MongoDB Atlas, Istio, and Google Kubernetes Engine, we built and deployed a microservice-based, cloud-native API to Google Kubernetes Engine, with Istio 1.0.x, on Google Cloud Platform. For brevity, we intentionally omitted a few key features required to operationalize and secure the API. These missing features included HTTPS, user authentication, request quotas, request throttling, and the integration of a full lifecycle API management tool, like Google Apigee.

In a follow-up post, Securing Your Istio Ingress Gateway with HTTPS, we disabled HTTP access to the API running on the GKE cluster. We then enabled bidirectional encryption of communications between a client and GKE cluster with HTTPS.

In this post, we will further enhance the security of the Storefront Demo API by enabling Istio end-user authentication using JSON Web Token-based credentials. Using JSON Web Tokens (JWT), pronounced ‘jot’, will allow Istio to authenticate end-users calling the Storefront Demo API. We will use Auth0, an Authentication-as-a-Service provider, to generate JWT tokens for registered Storefront Demo API consumers, and to validate JWT tokens from Istio, as part of an OAuth 2.0 token-based authorization flow.


JSON Web Tokens

Token-based authentication, according to Auth0, works by ensuring that each request to a server is accompanied by a signed token which the server verifies for authenticity and only then responds to the request. JWT, according to, is an open standard (RFC 7519) that defines a compact and self-contained way for securely transmitting information between parties as a JSON object. This information can be verified and trusted because it is digitally signed. Other common token types include Simple Web Tokens (SWT) and Security Assertion Markup Language Tokens (SAML).

JWTs can be signed using a secret with the Hash-based Message Authentication Code (HMAC) algorithm, or a public/private key pair using Rivest–Shamir–Adleman (RSA) or Elliptic Curve Digital Signature Algorithm (ECDSA). Authorization is the most common scenario for using JWT. Within the token payload, you can easily specify user roles and permissions as well as resources that the user can access.

A registered API consumer makes an initial request to the Authorization server, in which they exchange some form of credentials for a token. The JWT is associated with a set of specific user roles and permissions. Each subsequent request will include the token, allowing the user to access authorized routes, services, and resources that are permitted with that token.


To use JWTs for end-user authentication with Istio, we need a way to authenticate credentials associated with specific users and exchange those credentials for a JWT. Further, we need a way to validate the JWTs from Istio. To meet these requirements, we will use Auth0. Auth0 provides a universal authentication and authorization platform for web, mobile, and legacy applications. According to G2 Crowd, competitors to Auth0 in the Customer Identity and Access Management (CIAM) Software category include Okta, Microsoft Azure Active Directory (AD) and AD B2C, Salesforce Platform: Identity, OneLogin, Idaptive, IBM Cloud Identity Service, and Bitium.


Auth0 currently offers four pricing plans: Free, Developer, Developer Pro, and Enterprise. Subscriptions to plans are on a monthly or discounted yearly basis. For this demo’s limited requirements, you need only use Auth0’s Free Plan.


Client Credentials Grant

The OAuth 2.0 protocol defines four flows, or grants types, to get an Access Token, depending on the application architecture and the type of end-user. We will be simulating a third-party, external application that needs to consume the Storefront API, using the Client Credentials grant type. According to Auth0, The Client Credentials Grant, defined in The OAuth 2.0 Authorization Framework RFC 6749, section 4.4, allows an application to request an Access Token using its Client Id and Client Secret. It is used for non-interactive applications, such as a CLI, a daemon, or a Service running on your backend, where the token is issued to the application itself, instead of an end user.


With Auth0, we need to create two types of entities, an Auth0 API and an Auth0 Application. First, we define an Auth0 API, which represents the Storefront API we are securing. Second, we define an Auth0 Application, a consumer of our API. The Application is associated with the API. This association allows the Application (consumer of the API) to authenticate with Auth0 and receive a JWT. Note there is no direct integration between Auth0 and Istio or the Storefront API. We are facilitating a decoupled, mutual trust relationship between Auth0, Istio, and the registered end-user application consuming the API.

Start by creating a new Auth0 API, the ‘Storefront Demo API’. For this demo, I used my domain’s URL as the Identifier. For use with Istio, choose RS256 (RSA Signature with SHA-256), an asymmetric algorithm that uses a public/private key pair, as opposed to the HS256 symmetric algorithm. With RS256, Auth0 will use the same private key to both create the signature and to validate it. Auth0 has published a good post on the use of RS256 vs. HS256 algorithms.




Auth0 allows granular access control to your API through the use of Scopes. The permissions represented by the Access Token in OAuth 2.0 terms are known as scopes, According to Auth0. The scope parameter allows the application to express the desired scope of the access request. The scope parameter can also be used by the authorization server in the response to indicate which scopes were actually granted.

Although it is necessary to define and assign at least one scope to our Auth0 Application, we will not actually be using those scopes to control fine-grain authorization to resources within the Storefront API. In this demo, if an end-user is authenticated, they will be authorized to access all Storefront API resources.


Machine to Machine Applications

Next, define a new Auth0 Machine to Machine (M2M) Application, ‘Storefront Demo API Consumer 1’.


Next, authorize the new M2M Application to request access to the new Storefront Demo API. Again, we are not using scopes, but at least one scope is required, or you will not be able to authenticate, later.


Each M2M Application has a unique Client ID and Client Secret, which are used to authenticate with the Auth0 server and retrieve a JWT.


Multiple M2M Applications may be authorized to request access to APIs.


In the Endpoints tab of the Advanced Application Settings, there are a series of OAuth URLs. To authorize our new M2M Application to consume the Storefront Demo API, we need the ‘OAuth Authorization URL’.


Testing Auth0

To test the Auth0 JWT-based authentication and authorization workflow, I prefer to use Postman. Conveniently, Auth0 provides a Postman Collection with all the HTTP request you will need, already built. Use the Client Credentials POST request. The grant_type header value will always be client_credentials. You will need to supply the Auth0 Application’s Client ID and Client Secret as the client_id and client_secret header values. The audience header value will be the API Identifier you used to create the Auth0 API earlier.


If the HTTP request is successful, you should receive a JWT access_token in response, which will allow us to authenticate with the Storefront API, later. Note the scopes you defined with Auth0 are also part of the response, along with the token’s TTL. Debugger

For now, test the JWT using the Debugger page. If everything is working correctly, the JWT should be successfully validated.


Istio Authentication Policy

To enable Istio end-user authentication using JWT with Auth0, we add an Istio Policy authentication resource to the existing set of deployed resources. You have a few choices for end-user authentication, such as:

  1. Applied globally, to all Services across all Namespaces via the Istio Ingress Gateway;
  2. Applied locally, to all Services within a specific Namespace (i.e. uat);
  3. Applied locally, to a single Service or Services within a specific Namespace (i.e prod.accounts);

In reality, since you would likely have more than one registered consumer of the API, with different roles, you would have more than one Authentication Policy applied the cluster.

For this demo, we will enable global end-user authentication to the Storefront API, using JWTs, at the Istio Ingress Gateway. To create an Istio Authentication Policy resource, we use the Istio Authentication API version

The single audiences YAML map value is the same Audience header value you used in your earlier Postman request, which was the API Identifier you used to create the Auth0 Storefront Demo API earlier. The issuer YAML scalar value is Auth0 M2M Application’s Domain value, found in the ‘Storefront Demo API Consumer 1’ Settings tab. The jwksUri YAML scalar value is the JSON Web Key Set URL value, found in the Endpoints tab of the Advanced Application Settings.


The JSON Web Key Set URL is a publicly accessible endpoint. This endpoint will be accessed by Istio to obtain the public key used to authenticate the JWT.


Assuming you have already have deployed the Storefront API to the GKE cluster, simply apply the new Istio Policy. We should now have end-user authentication enabled on the Istio Ingress Gateway using JSON Web Tokens.

kubectl apply -f ./resources/other/ingressgateway-jwt-policy.yaml

Finer-grain Authentication

If you need finer-grain authentication of resources, alternately, you can apply an Istio Authentication Policy across a Namespace and to a specific Service or Services. Below, we see an example of applying a Policy to only the uat Namespace. This scenario is common when you want to control access to resources in non-production environments, such as UAT, to outside test teams or a select set of external beta-testers. According to Istio, to apply Namespace-wide end-user authentication, across a single Namespace, it is necessary to name the Policy, default (gist).

Below, we see an even finer-grain Policy example, scoped to just the accounts Service within just the prod Namespace. This scenario is common when you have an API consumer whose role only requires access to a portion of the API. For example, a marketing application might only require access to the accounts Service, but not the orders or fulfillment Services (gist).

Test Authentication

To test end-user authentication, first, call any valid Storefront Demo API endpoint, without supplying a JWT for authorization. You should receive a ‘401 Unauthorized’ HTTP response code, along with an Origin authentication failed. message in the response body. This means the Storefront Demo API is now inaccessible unless the API consumer supplies a JWT, which can be successfully validated by Istio.


Next, add authorization to the Postman request by selecting the ‘Bearer Token’ type authentication method. Copy and paste the JWT (access_token) you received earlier from the Client Credentials request. This will add an Authorization request header. In curl, the request header would look as follows (gist).

Make the request with Postman. If the Istio Policy is applied correctly, the request should now receive a successful response from the Storefront API. A successful response indicates that Istio successfully validated the JWT, located in the Authorization header, against the Auth0 Authorization Server. Istio then allows the user, the ‘Storefront Demo API Consumer 1’ application, access to all Storefront API resources.



Istio has several pages of online documentation on troubleshooting authentication issues. One of the first places to look for errors, if your end-user authentication is not working, but the JWT is valid, is the Istio Pilot logs. The core component used for traffic management in Istio, Pilot, manages and configures all the Envoy proxy instances deployed in a particular Istio service mesh. Pilot distributes authentication policies, like our new end-user authentication policy, and secure naming information to the proxies.

Below, in Google Stackdriver Logging, we see typical log entries indicating the Pilot was unable to retrieve the JWT public key (recall we are using RS256 public/private key pair asymmetric algorithm). This particular error was due to a typo in the Istio Policy authentication resource YAML file.


Below we see an Istio Mixer log entry containing details of a Postman request to the Accounts Storefront service /accounts/customers/summary endpoint. According to Istio, Mixer is the Istio component responsible for providing policy controls and telemetry collection. Note the apiClaims section of the textPayload of the log entry, corresponds to the Payload Segment of the JWT passed in this request. The log entry clearly shows that the JWT was decoded and validated by Istio, before forwarding the request to the Accounts Service.



In this brief post, we added end-user authentication to our Storefront Demo API, running on GKE with Istio. Although still not Production-ready, we have secured the Storefront API with both HTTPS client-server encryption and JSON Web Token-based authorization. Next steps would be to add mutual TLS (mTLS) and a fully-managed API Gateway in front of the Storefront API GKE cluster, to provide advanced API features, like caching, quotas and rate limits.

All opinions expressed in this post are my own and not necessarily the views of my current or past employers or their clients.

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Using Eventual Consistency and Spring for Kafka to Manage a Distributed Data Model: Part 2

Given a modern distributed system, composed of multiple microservices, each possessing a sub-set of the domain’s aggregate data they need to perform their functions autonomously, we will almost assuredly have some duplication of data. Given this duplication, how do we maintain data consistency? In this two-part post, we’ve been exploring one possible solution to this challenge, using Apache Kafka and the model of eventual consistency. In Part One, we examined the online storefront domain, the storefront’s microservices, and the system’s state change event message flows.

Part Two

In Part Two of this post, I will briefly cover how to deploy and run a local development version of the storefront components, using Docker. The storefront’s microservices will be exposed through an API Gateway, Netflix’s Zuul. Service discovery and load balancing will be handled by Netflix’s Eureka. Both Zuul and Eureka are part of the Spring Cloud Netflix project. To provide operational visibility, we will add Yahoo’s Kafka Manager and Mongo Express to our system.


Source code for deploying the Dockerized components of the online storefront, shown in this post, is available on GitHub. All Docker Images are available on Docker Hub. I have chosen the wurstmeister/kafka-docker version of Kafka, available on Docker Hub; it has 580+ stars and 10M+ pulls on Docker Hub. This version of Kafka works well, as long as you run it within a Docker Swarm, locally.

Code samples in this post are displayed as Gists, which may not display correctly on some mobile and social media browsers. Links to gists are also provided.

Deployment Options

For simplicity, I’ve used Docker’s native Docker Swarm Mode to support the deployed online storefront. Docker requires minimal configuration as opposed to other CaaS platforms. Usually, I would recommend Minikube for local development if the final destination of the storefront were Kubernetes in Production (AKS, EKS, or GKE). Alternatively, if the final destination of the storefront were Red Hat OpenShift in Production, I would recommend Minishift for local development.

Docker Deployment

We will break up our deployment into two parts. First, we will deploy everything, except our services. We will allow Kafka, MongoDB, Eureka, and the other components to startup up fully. Afterward, we will deploy the three online storefront services. The storefront-kafka-docker project on Github contains two Docker Compose files, which are divided between the two tasks.

The middleware Docker Compose file (gist).

The services Docker Compose file (gist).

In the storefront-kafka-docker project, there is a shell script, This script will execute both Docker Compose files, in succession, with a pause in between. You may need to adjust the timing for your own system (gist).

Start by running docker swarm init. This command will initialize a Docker Swarm. Next, execute the stack deploy script, using an sh ./ command. The script will deploy a new Docker Stack, within the Docker Swarm. The Docker Stack will hold all storefront components, deployed as individual Docker containers. The stack is deployed within its own isolated Docker overlay networkkafka-net.

Note we are not using host-based persistent storage for this local development demo. Destroying the Docker stack or the individual Kafka, Zookeeper, or MongoDB Docker containers will result in a loss of data.


Before completion, the stack deploy script runs docker stack ls command, followed by a docker stack services storefront command. You should see one stack, names storefront, with ten services. You should also see each of the ten services has 1/1 replicas running, indicated everything has started or is starting correctly, without failure. A failure would be reflected here as a service having 0/1 replicas.


Before completion, the stack deploy script also runs docker container ls command. You should observe each of the ten running containers (‘services’ in the Docker stack), along with their instance names and ports.


There is also a shell script,, which will issue a docker stack rm storefront command to destroy the stack when you are done.

Using the names of the storefront’s Docker containers, you can check the start-up logs of any of the components, using the docker logs command.


Testing the Stack

With the storefront stack deployed, we need to confirm that all the components have started correctly and are communicating with each other. To accomplish this, I’ve written a simple Python script, The refresh script has multiple uses. It deletes any existing storefront service MongoDB databases. It also deletes any existing Kafka topics; I call the Kafka Manager’s API to accomplish this. We have no databases or topics since our stack was just created. However, if you are actively developing your data models, you will likely want to purge the databases and topics regularly (gist).

Next, the refresh script calls a series of RESTful HTTP endpoints, in a specific order, to create sample data. Our three storefront services each expose different endpoints. The different /sample endpoints create sample customers, orders, order fulfillment requests, and shipping notifications. The create sample data endpoints include, in order:

  1. Sample Customer: /accounts/customers/sample
  2. Sample Orders: /orders/customers/sample/orders
  3. Sample Fulfillment Requests: /orders/customers/sample/fulfill
  4. Sample Processed Order Events: /fulfillment/fulfillment/sample/process
  5. Sample Shipped Order Events: /fulfillment/fulfillment/sample/ship
  6. Sample In-Transit Order Events: /fulfillment/fulfillment/sample/in-transit
  7. Sample Received Order Events: /fulfillment/fulfillment/sample/receive

You could create data on your own, by POSTing to the exposed CRUD endpoints on each service. However, given the complex data objects required in the request payloads, it is too time-consuming for this demo.

To execute the script, use a python3 ./ command. I am using Python 3 in the demo, but the script should also work with Python 2.x if you change shebang.


If everything was successful, the script returns one document from each of the three storefront service’s MongoDB database collections. A result of ‘None’ for any of the MongoDB documents usually indicates one of the earlier commands failed. Given an abnormally high response latency, due to the load of the ten running containers on my laptop, I had to increase the Zuul/Ribbon timeouts.

Observing the System

We should now have the online storefront Docker stack running, three MongoDB databases created and populated with sample documents (data), and three Kafka topics, which have messages in them. Based on the fact we saw database documents printed out with our refresh script, we know the topics were used to pass data between the message producing and message consuming services.

In most enterprise environments, a developer may not the access, nor the operational knowledge to interact with Kafka or MongoDB from within a container, on the command line. So how else can we interact with the system?

Kafka Manager

Kafka Manager gives us the ability to interact with Kafka via a convenient browser-based user interface. For this demo, the Kafka Manager UI is available on default port 9000.


To make Kafka Manager useful, define the Kafka cluster. The Cluster Name is up to you. The Cluster Zookeeper Host should be zookeeper:2181, for our demo.


Kafka Manager gives us useful insights into many aspects of our simple, single-broker cluster. You should observe three topics, created during the deployment of Kafka.


Kafka Manager is an appealing alternative, as opposed to connecting with the Kafka container, with a docker exec command, to interact with Kafka. A typical use case might be deleting a topic or adding partitions to a topic. We can also see which Consumers are consuming which topics, from within Kafka Manager.


Mongo Express

Similar to Kafka Manager, Mongo Express gives us the ability to interact with Kafka via a user interface. For this demo, the Mongo Express browser-based user interface is available on default port 8081. The initial view displays each of the existing databases. Note our three service’s databases, including accounts, orders, and fulfillment.


Drilling into an individual database, we can view each of the database’s collections. Digging in further, we can interact with individual database collection documents.


We may even edit and save the documents.


SpringFox and Swagger

Each of the storefront services also implements SpringFox, the automated JSON API documentation for API’s built with Spring. With SpringFox, each service exposes a rich Swagger UI. The Swagger UI allows us to interact with service endpoints.

Since each service exposes its own Swagger interface, we must access them through the Zuul API Gateway on port 8080. In our demo environment, the Swagger browser-based user interface is accessible at /swagger-ui.html. Below, is a fully self-documented Orders service API, as seen through the Swagger UI.

I believe there are still some incompatibilities with the latest SpringFox release and Spring Boot 2, which prevents Swagger from showing the default Spring Data REST CRUD endpoints. Currently, you only see the API  endpoints you explicitly declare in your Controller classes.


The service’s data models (POJOs) are also exposed through the Swagger UI by default. Below we see the Orders service’s models.


The Swagger UI allows you to drill down into the complex structure of the models, such as the CustomerOrder entity, exposing each of the entity’s nested data objects.


Spring Cloud Netflix Eureka

This post does not cover the use of Eureka or Zuul. Eureka gives us further valuable insight into our storefront system. Eureka is our systems service registry and provides load-balancing for our services if we had multiple instances.

For this demo, the Eureka browser-based user interface is available on default port 8761. Within the Eureka user interface, we should observe the three storefront services and Zuul, the API Gateway, registered with Eureka. If we had more than one instance of each service, we would see all of them listed here.


Although of limited use in a local environment, we can observe some general information about our host.


Interacting with the Services

The three storefront services are fully functional Spring Boot / Spring Data REST / Spring HATEOAS-enabled applications. Each service exposes a rich set of CRUD endpoints for interacting with the service’s data entities. Additionally, each service includes Spring Boot Actuator. Actuator exposes additional operational endpoints, allowing us to observe the running services. Again, this post is not intended to be a demonstration of Spring Boot or Spring Boot Actuator.

Using an application, such as Postman, we can interact with our service’s RESTful HTTP endpoints. Shown below, we are calling the Account service’s customers resource. The Accounts request is proxied through the Zuul API Gateway.


The above Postman Storefront Collection and Postman Environment are both exported and saved with the project.

Some key endpoints to observe the entities that were created using Event-Carried State Transfer are as follows. They assume you are using localhost as a base URL.


Links to my GitHub projects for this post

Some additional references I found useful while authoring this post and the online storefront code:

All opinions expressed in this post are my own and not necessarily the views of my current or past employers or their clients.


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Architecting Cloud-Optimized Apps with AKS (Azure’s Managed Kubernetes), Azure Service Bus, and Cosmos DB

An earlier post, Eventual Consistency: Decoupling Microservices with Spring AMQP and RabbitMQ, demonstrated the use of a message-based, event-driven, decoupled architectural approach for communications between microservices, using Spring AMQP and RabbitMQ. This distributed computing model is known as eventual consistency. To paraphrase, ‘using an event-driven, eventually consistent approach, each service publishes an event whenever it updates its data. Other services subscribe to events. When an event is received, a service (subscriber) updates its data.

That earlier post illustrated a fairly simple example application, the Voter API, consisting of a set of three Spring Boot microservices backed by MongoDB and RabbitMQ, and fronted by an API Gateway built with HAProxy. All API components were containerized using Docker and designed for use with Docker CE for AWS as the Container-as-a-Service (CaaS) platform.

Optimizing for Kubernetes on Azure

This post will demonstrate how a modern application, such as the Voter API, is optimized for Kubernetes in the Cloud (Kubernetes-as-a-Service), in this case, AKS, Azure’s new public preview of Managed Kubernetes for Azure Container Service. According to Microsoft, the goal of AKS is to simplify the deployment, management, and operations of Kubernetes. I wrote about AKS in detail, in my last post, First Impressions of AKS, Azure’s New Managed Kubernetes Container Service.

In addition to migrating to AKS, the Voter API will take advantage of additional enterprise-grade Azure’s resources, including Azure’s Service Bus and Cosmos DB, replacements for the Voter API’s RabbitMQ and MongoDB. There are several architectural options for the Voter API’s messaging and NoSQL data source requirements when moving to Azure.

  1. Keep Dockerized RabbitMQ and MongoDB – Easy to deploy to Kubernetes, but not easily scalable, highly-available, or manageable. Would require storage optimized Azure VMs for nodes, node affinity, and persistent storage for data.
  2. Replace with Cloud-based Non-Azure Equivalents – Use SaaS-based equivalents, such as CloudAMQP (RabbitMQ-as-a-Service) and MongoDB Atlas, which will provide scalability, high-availability, and manageability.
  3. Replace with Azure Service Bus and Cosmos DB – Provides all the advantages of  SaaS-based equivalents, and additionally as Azure resources, benefits from being in the Azure Cloud alongside AKS.

Source Code

The Kubernetes resource files and deployment scripts used in this post are all available on GitHub. This is the only project you need to clone to reproduce the AKS example in this post.

git clone \
  --branch master --single-branch --depth 1 --no-tags \

The Docker images for the three Spring microservices deployed to AKS, Voter, Candidate, and Election, are available on Docker Hub. Optionally, the source code, including Dockerfiles, for the Voter, Candidate, and Election microservices, as well as the Voter Client are available on GitHub, in the kub-aks branch.

git clone \
  --branch kub-aks --single-branch --depth 1 --no-tags \

git clone \
  --branch kub-aks --single-branch --depth 1 --no-tags \

git clone \
  --branch kub-aks --single-branch --depth 1 --no-tags \

git clone \
  --branch kub-aks --single-branch --depth 1 --no-tags \

Azure Service Bus

To demonstrate the capabilities of Azure’s Service Bus, the Voter API’s Spring microservice’s source code has been re-written to work with Azure Service Bus instead of RabbitMQ. A future post will explore the microservice’s messaging code. It is more likely that a large application, written specifically for a technology that is easily portable such as RabbitMQ or MongoDB, would likely remain on that technology, even if the application was lifted and shifted to the Cloud or moved between Cloud Service Providers (CSPs). Something important to keep in mind when choosing modern technologies – portability.

Service Bus is Azure’s reliable cloud Messaging-as-a-Service (MaaS). Service Bus is an original Azure resource offering, available for several years. The core components of the Service Bus messaging infrastructure are queues, topics, and subscriptions. According to Microsoft, ‘the primary difference is that topics support publish/subscribe capabilities that can be used for sophisticated content-based routing and delivery logic, including sending to multiple recipients.

Since the three Voter API’s microservices are not required to produce messages for more than one other service consumer, Service Bus queues are sufficient, as opposed to a pub/sub model using Service Bus topics.

Cosmos DB

Cosmos DB, Microsoft’s globally distributed, multi-model database, offers throughput, latency, availability, and consistency guarantees with comprehensive service level agreements (SLAs). Ideal for the Voter API, Cosmos DB supports MongoDB’s data models through the MongoDB API, a MongoDB database service built on top of Cosmos DB. The MongoDB API is compatible with existing MongoDB libraries, drivers, tools, and applications. Therefore, there are no code changes required to convert the Voter API from MongoDB to Cosmos DB. I simply had to change the database connection string.

NGINX Ingress Controller

Although the Voter API’s HAProxy-based API Gateway could be deployed to AKS, it is not optimal for Kubernetes. Instead, the Voter API will use an NGINX-based Ingress Controller. NGINX will serve as an API Gateway, as HAProxy did, previously.

According to NGINX, ‘an Ingress is a Kubernetes resource that lets you configure an HTTP load balancer for your Kubernetes services. Such a load balancer usually exposes your services to clients outside of your Kubernetes cluster.

An Ingress resource requires an Ingress Controller to function. Continuing from NGINX, ‘an Ingress Controller is an application that monitors Ingress resources via the Kubernetes API and updates the configuration of a load balancer in case of any changes. Different load balancers require different Ingress controller implementations. In the case of software load balancers, such as NGINX, an Ingress controller is deployed in a pod along with a load balancer.

There are currently two NGINX-based Ingress Controllers available, one from Kubernetes and one directly from NGINX. Both being equal, for this post, I chose the Kubernetes version, without RBAC (Kubernetes offers a version with and without RBAC). RBAC should always be used for actual cluster security. There are several advantages of using either version of the NGINX Ingress Controller for Kubernetes, including Layer 4 TCP and UDP and Layer 7 HTTP load balancing, reverse proxying, ease of SSL termination, dynamically-configurable path-based rules, and support for multiple hostnames.

Azure Web App

Lastly, the Voter Client application, not really part of the Voter API, but useful for demonstration purposes, will be converted from a containerized application to an Azure Web App. Since it is not part of the Voter API, separating the Client application from AKS makes better architectural sense. Web Apps are a powerful, richly-featured, yet incredibly simple way to host applications and services on Azure. For more information on using Azure Web Apps, read my recent post, Developing Applications for the Cloud with Azure App Services and MongoDB Atlas.

Revised Component Architecture

Below is a simplified component diagram of the new architecture, including Azure Service Bus, Cosmos DB, and the NGINX Ingress Controller. The new architecture looks similar to the previous architecture, but as you will see, it is actually very different.


Process Flow

To understand the role of each API component, let’s look at one of the event-driven, decoupled process flows, the creation of a new election candidate. In the simplified flow diagram below, an API consumer executes an HTTP POST request containing the new candidate object as JSON. The Candidate microservice receives the HTTP request and creates a new document in the Cosmos DB Voter database. A Spring RepositoryEventHandler within the Candidate microservice responds to the document creation and publishes a Create Candidate event message, containing the new candidate object as JSON, to the Azure Service Bus Candidate Queue.


Independently, the Voter microservice is listening to the Candidate Queue. Whenever a new message is produced by the Candidate microservice, the Voter microservice retrieves the message off the queue. The Voter microservice then transforms the new candidate object contained in the incoming message to its own candidate data model and creates a new document in its own Voter database.


The same process flows exist between the Election and the Candidate microservices. The Candidate microservice maintains current elections in its database, which are retrieved from the Election queue.

Data Models

It is useful to understand, the Candidate microservice’s candidate domain model is not necessarily identical to the Voter microservice’s candidate domain model. Each microservice may choose to maintain its own representation of a vote, a candidate, and an election. The Voter service transforms the new candidate object in the incoming message based on its own needs. In this case, the Voter microservice is only interested in a subset of the total fields in the Candidate microservice’s model. This is the beauty of decoupling microservices, their domain models, and their datastores.

Other Events

The versions of the Voter API microservices used for this post only support Election Created events and Candidate Created events. They do not handle Delete or Update events, which would be necessary to be fully functional. For example, if a candidate withdraws from an election, the Voter service would need to be notified so no one places votes for that candidate. This would normally happen through a Candidate Delete or Candidate Update event.

Provisioning Azure Service Bus

First, the Azure Service Bus is provisioned. Provisioning the Service Bus may be accomplished using several different methods, including manually using the Azure Portal or programmatically using Azure Resource Manager (ARM) with PowerShell or Terraform. I chose to provision the Azure Service Bus and the two queues using the Azure Portal for expediency. I chose the Basic Service Bus Tier of service, of which there are three tiers, Basic, Standard, and Premium.


The application requires two queues, the candidate.queue, and the election.queue.


Provisioning Cosmos DB

Next, Cosmos DB is provisioned. Like Azure Service Bus, Cosmos DB may be provisioned using several methods, including manually using the Azure Portal, programmatically using Azure Resource Manager (ARM) with PowerShell or Terraform, or using the Azure CLI, which was my choice.

az cosmosdb create \
  --name cosmosdb_instance_name_goes_here \
  --resource-group resource_group_name_goes_here \
  --location "East US=0" \
  --kind MongoDB

The post’s Cosmos DB instance exists within the single East US Region, with no failover. In a real Production environment, you would configure Cosmos DB with multi-region failover. I chose MongoDB as the type of Cosmos DB database account to create. The allowed values are GlobalDocumentDB, MongoDB, Parse. All other settings were left to the default values.

The three Spring microservices each have their own database. You do not have to create the databases in advance of consuming the Voter API. The databases and the database collections will be automatically created when new documents are first inserted by the microservices. Below, the three databases and their collections have been created and populated with documents.


The GitHub project repository also contains three shell scripts to generate sample vote, candidate, and election documents. The scripts will delete any previous documents from the database collections and generate new sets of sample documents. To use, you will have to update the scripts with your own Voter API URL.


MongoDB Aggregation Pipeline

Each of the three Spring microservices uses Spring Data MongoDB, which takes advantage of MongoDB’s Aggregation Framework. According to MongoDB, ‘the aggregation framework is modeled on the concept of data processing pipelines. Documents enter a multi-stage pipeline that transforms the documents into an aggregated result.’ Below is an example of aggregation from the Candidate microservice’s VoterContoller class.

Aggregation aggregation = Aggregation.newAggregation(
    sort(Sort.Direction.DESC, "votes")

To use MongoDB’s aggregation framework with Cosmos DB, it is currently necessary to activate the MongoDB Aggregation Pipeline Preview Feature of Cosmos DB. The feature can be activated from the Azure Portal, as shown below.


Cosmos DB Emulator

Be warned, Cosmos DB can be very expensive, even without database traffic or any Production-grade bells and whistles. Be careful when spinning up instances on Azure for learning purposes, the cost adds up quickly! In less than ten days, while writing this post, my cost was almost US$100 for the Voter API’s Cosmos DB instance.

I strongly recommend downloading the free Azure Cosmos DB Emulator to develop and test applications from your local machine. Although certainly not as convenient, it will save you the cost of developing for Cosmos DB directly on Azure.

With Cosmos DB, you pay for reserved throughput provisioned and data stored in containers (a collection of documents or a table or a graph). Yes, that’s right, Azure charges you per MongoDB collection, not even per database. Azure Cosmos DB’s current pricing model seems less than ideal for microservice architectures, each with their own database instance.

By default the reserved throughput, billed as Request Units (RU) per second or RU/s, is set to 1,000 RU/s per collection. For development and testing, you can reduce each collection to a minimum of 400 RU/s. The Voter API creates five collections at 1,000 RU/s or 5,000 RU/s total. Reducing this to a total of 2,000 RU/s makes Cosmos DB marginally more affordable to explore.


Building the AKS Cluster

An existing Azure Resource Group is required for AKS. I chose to use the latest available version of Kubernetes, 1.8.2.

# login to azure
az login \
  --username your_username  \
  --password your_password

# create resource group
az group create \
  --resource-group resource_group_name_goes_here \
  --location eastus

# create aks cluster
az aks create \
  --name cluser_name_goes_here \
  --resource-group resource_group_name_goes_here \
  --ssh-key-value path_to_your_public_key \
  --kubernetes-version 1.8.2

# get credentials to access aks cluster
az aks get-credentials \
  --name cluser_name_goes_here \
  --resource-group resource_group_name_goes_here

# display cluster's worker nodes
kubectl get nodes --output=wide

By default, AKS will provision a three-node Kubernetes cluster using Azure’s Standard D1 v2 Virtual Machines. According to Microsoft, ‘D series VMs are general purpose VM sizes provide balanced CPU-to-memory ratio. They are ideal for testing and development, small to medium databases, and low to medium traffic web servers.’ Azure D1 v2 VM’s are based on Linux OS images, currently Debian 8 (Jessie), with 1 vCPU and 3.5 GB of memory. By default with AKS, each VM receives 30 GiB of Standard HDD attached storage.

You should always select the type and quantity of the cluster’s VMs and their attached storage, optimized for estimated traffic volumes and the specific workloads you are running. This can be done using the --node-count--node-vm-size, and --node-osdisk-size arguments with the az aks create command.


The Voter API resources are deployed to its own Kubernetes Namespace, voter-api. The NGINX Ingress Controller resources are deployed to a different namespace, ingress-nginx. Separate namespaces help organize individual Kubernetes resources and separate different concerns.

Voter API

First, the voter-api namespace is created. Then, five required Kubernetes Secrets are created within the namespace. These secrets all contain sensitive information, such as passwords, that should not be shared. There is one secret for each of the three Cosmos DB database connection strings, one secret for the Azure Service Bus connection string, and one secret for the Let’s Encrypt SSL/TLS certificate and private key, used for secure HTTPS access to the Voter API.



The Voter API’s secrets are used to populate environment variables within the pod’s containers. The environment variables are then available for use within the containers. Below is a snippet of the Voter pods resource file showing how the Cosmos DB and Service Bus connection strings secrets are used to populate environment variables.

        name: azure-service-bus
        key: connection-string
        name: azure-cosmosdb-voter
        key: connection-string

Shown below, the Cosmos DB and Service Bus connection strings secrets have been injected into the Voter container and made available as environment variables to the microservice’s executable JAR file on start-up. As environment variables, the secrets are visible in plain text. Access to containers should be tightly controlled through Kubernetes RBAC and Azure AD, to ensure sensitive information, such as secrets, remain confidential.


Next, the three Kubernetes ReplicaSet resources, corresponding to the three Spring microservices, are created using Deployment controllers. According to Kubernetes, a Deployment that configures a ReplicaSet is now the recommended way to set up replication. The Deployments specify three replicas of each of the three Spring Services, resulting in a total of nine Kubernetes Pods.

Each pod, by default, will be scheduled on a different node if possible. According to Kubernetes, ‘the scheduler will automatically do a reasonable placement (e.g. spread your pods across nodes, not place the pod on a node with insufficient free resources, etc.).’ Note below how each of the three microservice’s three replicas has been scheduled on a different node in the three-node AKS cluster.


Next, the three corresponding Kubernetes ClusterIP-type Services are created. And lastly, the Kubernetes Ingress is created. According to Kubernetes, the Ingress resource is an API object that manages external access to the services in a cluster, typically HTTP. Ingress provides load balancing, SSL termination, and name-based virtual hosting.

The Ingress configuration contains the routing rules used with the NGINX Ingress Controller. Shown below are the routing rules for each of the three microservices within the Voter API. Incoming API requests are routed to the appropriate pod and service port by NGINX.

apiVersion: extensions/v1beta1
kind: Ingress
  name: voter-ingress
  namespace: voter-api
  annotations: "true"
  - hosts:
    secretName: api-voter-demo-secret
  - http:
      - path: /candidate
          serviceName: candidate
          servicePort: 8080
      - path: /election
          serviceName: election
          servicePort: 8080
      - path: /voter
          serviceName: voter
          servicePort: 8080

The screengrab below shows all of the Voter API resources created on AKS.


NGINX Ingress Controller

After completing the deployment of the Voter API, the NGINX Ingress Controller is created. It starts with creating the ingress-nginx namespace. Next, the NGINX Ingress Controller is created, consisting of the NGINX Ingress Controller, three Kubernetes ConfigMap resources, and a default back-end application. The Controller and backend each have their own Service resources. Like the Voter API, each has three replicas, for a total of six pods. Together, the Ingress resource and NGINX Ingress Controller manage traffic to the Spring microservices.

The screengrab below shows all of the NGINX Ingress Controller resources created on AKS.


The  NGINX Ingress Controller Service, shown above, has an external public IP address associated with itself.  This is because that Service is of the type, Load Balancer. External requests to the Voter API will be routed through the NGINX Ingress Controller, on this IP address.

kind: Service
apiVersion: v1
  name: ingress-nginx
  namespace: ingress-nginx
    app: ingress-nginx
  externalTrafficPolicy: Local
  type: LoadBalancer
    app: ingress-nginx
  - name: http
    port: 80
    targetPort: http
  - name: https
    port: 443
    targetPort: https

If you are only using HTTPS, not HTTP, then the references to HTTP and port 80 in the Ingress configuration are unnecessary. The NGINX Ingress Controller’s resources are explained in detail in the GitHub documentation, along with further configuration instructions.


To provide convenient access to the Voter API and the Voter Client, my domain,, is associated with the public IP address associated with the Voter API Ingress Controller and with the public IP address associated with the Voter Client Azure Web App. DNS configuration is done through Azure’s DNS Zone resource.


The two TXT type records might not look as familiar as the SOA, NS, and A type records. The TXT records are required to associate the domain entries with the Voter Client Azure Web App. Browsing to or simply brings up the Voter Client.


The Client sends and receives data via the Voter API, available securely at

Routing API Requests

With the Pods, Services, Ingress, and NGINX Ingress Controller created and configured, as well as the Azure Layer 4 Load Balancer and DNS Zone, HTTP requests from API consumers are properly and securely routed to the appropriate microservices. In the example below, three back-to-back requests are made to the voter/info API endpoint. HTTP requests are properly routed to one of the three Voter pod replicas using the default round-robin algorithm, as proven by the observing the different hostnames (pod names) and the IP addresses (private pod IPs) in each HTTP response.


Final Architecture

Shown below is the final Voter API Azure architecture. To simplify the diagram, I have deliberately left out the three microservice’s ClusterIP-type Services, the three default back-end application pods, and the default back-end application’s ClusterIP-type Service. All resources shown below are within the single East US Azure region, except DNS, which is a global resource.


Shown below is the new Azure Resource Group created by Azure during the AKS provisioning process. The Resource Group contains the various resources required to support the AKS cluster, NGINX Ingress Controller, and the Voter API. Necessary Azure resources were automatically provisioned when I provisioned AKS and when I created the new Voter API and NGINX resources.


In addition to the Resource Group above, the original Resource Group contains the AKS Container Service resource itself, Service Bus, Cosmos DB, and the DNS Zone resource.


The Voter Client Web App, consisting of the Azure App Service and App Service plan resource, is located in a third, separate Resource Group, not shown here.

Cleaning Up AKS

A nice feature of AKS, running a az aks delete command will delete all the Azure resources created as part of provisioning AKS, the API, and the Ingress Controller. You will have to delete the Cosmos DB, Service Bus, and DNS Zone resources, separately.

az aks delete \
  --name cluser_name_goes_here \
  --resource-group resource_group_name_goes_here


Taking advantage of Kubernetes with AKS, and the array of Azure’s enterprise-grade resources, the Voter API was shifted from a simple Docker architecture to a production-ready solution. The Voter API is now easier to manage, horizontally scalable, fault-tolerant, and marginally more secure. It is capable of reliably supporting dozens more microservices, with multiple replicas. The Voter API will handle a high volume of data transactions and event messages.

There is much more that needs to be done to productionalize the Voter API on AKS, including:

  • Add multi-region failover of Cosmos DB
  • Upgrade to Service Bus Standard or Premium Tier
  • Optimized Azure VMs and storage for anticipated traffic volumes and application-specific workloads
  • Implement Kubernetes RBAC
  • Add Monitoring, logging, and alerting with Envoy or similar
  • Secure end-to-end TLS communications with Itsio or similar
  • Secure the API with OAuth and Azure AD
  • Automate everything with DevOps – AKS provisioning, testing code, creating resources, updating microservices, and managing data

All opinions in this post are my own, and not necessarily the views of my current or past employers or their clients.

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Developing Applications for the Cloud with Azure App Services and MongoDB Atlas

Shift Left Cloud

The continued growth of compute services by leading Cloud Service Providers (CSPs) like Microsoft, Amazon, and Google are transforming the architecture of modern software applications, as well as the software development lifecycle (SDLC). Self-service access to fully-managed, reasonably-priced, secure compute has significantly increased developer productivity. At the same time, cloud-based access to cutting-edge technologies, like Artificial Intelligence (AI), Internet Of Things (IoT), Machine Learning, and Data Analytics, has accelerated the capabilities of modern applications. Finally, as CSPs become increasingly platform agnostic, Developers are no longer limited to a single technology stack or operating system. Today, Developers are solving complex problems with multi-cloud, multi-OS polyglot solutions.

Developers now leverage the Cloud from the very start of the software development process; shift left Cloud, if you will*. Developers are no longer limited to building and testing software on local workstations or on-premise servers, then throwing it over the wall to Operations for deployment to the Cloud. Developers using Azure, AWS, and GCP, develop, build, test, and deploy their code directly to the Cloud. Existing organizations are rapidly moving development environments from on-premise to the Cloud. New organizations are born in the Cloud, without the burden of legacy on-premise data-centers and servers under desks to manage.

Example Application

To demonstrate the ease of developing a modern application for the Cloud, let’s explore a simple API-based, NoSQL-backed web application. The application, The .NET Diner, simulates a rudimentary restaurant menu ordering interface. It consists of a single-page application (SPA) and two microservices backed by MongoDB. For simplicity, there is no API Gateway between the UI and the two services, as normally would be in place. An earlier version of this application was used in two previous posts, including Cloud-based Continuous Integration and Deployment for .NET Development.

The original restaurant order application was written with JQuery and RESTful .NET WCF Services. The new application, used in this post, has been completely re-written and modernized. The web-based user interface (UI) is written with Google’s Angular 4 framework using TypeScript. The UI relies on a microservices-based API, built with C# using Microsoft’s Web API 2 and .NET 4.7. The services rely on MongoDB for data persistence.


All code for this project is available on GitHub within two projects, one for the Angular UI and another for the C# services. The entire application can easily be built and run locally on Windows using MongoDB Community Edition. Alternately, to run the application in the Cloud, you will require an Azure and MongoDB Atlas account.

This post is primarily about the development experience. For brevity, the post will not delve into security, DevOps practices for CI/CD, and the complexities of staging and releasing code to Production.

Cross-Platform Development

The API, consisting of a set of C# microservices, was developed with Microsoft Visual Studio Community 2017 on Windows 10. Visual Studio touts itself as a full-featured Integrated Development Environment (IDE) for Android, iOS, Windows, web, and cloud. Visual Studio is easily integrated with Azure, AWS, and Google, through the use of Extensions. Visual Studio is an ideal IDE for cloud-centric application development.


To simulate a typical mixed-platform development environment, the Angular UI front-end was developed with JetBrains WebStorm 2017 on Mac OS X. WebStorm touts itself as a powerful IDE for modern JavaScript development.


Other tools used to develop the application include Git and GitHub for source code, MongoDB Community Edition for local database development, and Postman for API development and testing, both locally and on Azure. All the development tools used in the post are cross-platform. Versions of WebStorm, Visual Studio, MongoDB, Postman, Git, Node.js, npm, and Bash are all available for Mac, Windows, and Linux. Cross-platform flexibility is key when developing modern multi-OS polyglot applications.


Postman was used to build, test, and document the application’s API. Postman is an excellent choice for developing RESTful APIs. With Postman, you define Collections of HTTP requests for each of your APIs. You then define Environments, such as Development, Test, and Production, against which you will execute the Collections of HTTP requests. Each environment consists of environment-specific variables. Those variables can be used to define API URLs and as request parameters.

Not only can you define static variables, Postman’s runtime, built on Node.js, is scriptable using JavaScript, allowing you to programmatically set dynamic variables, based on the results of HTTP requests and responses, as demonstrated below.


Postman also allows you to write and run automated API integration tests, as well as perform load testing, as shown below.


Azure App Services

The Angular browser-based UI and the C# microservices will be deployed to Azure using the Azure App Service. Azure App Service is nearly identical to AWS Elastic BeanStalk and Google App Engine.  According to Microsoft, Azure App Service allows Developers to quickly build, deploy, and scale enterprise-grade web, mobile, and API apps, running on Windows or Linux, using .NET, .NET Core, Java, Ruby, Node.js, PHP, and Python.

App Service is a fully-managed, turn-key platform. Azure takes care of infrastructure maintenance and load balancing. App Service easily integrates with other Azure services, such as API Management, Queue Storage, Azure Active Directory (AD), Cosmos DB, and Application Insights. Microsoft suggests evaluating the following four criteria when considering Azure App Services:

  • You want to deploy a web application that’s accessible through the Internet.
  • You want to automatically scale your web application according to demand without needing to redeploy.
  • You don’t want to maintain server infrastructure (including software updates).
  • You don’t need any machine-level customizations on the servers that host your web application.

There are currently four types of Azure App Services, which are Web Apps, Web Apps for Containers, Mobile Apps, and API Apps. The application in this post will use the Azure Web Apps for the Angular browser-based UI and Azure API Apps for the C# microservices.

MongoDB Atlas

Each of the C# microservices has separate MongoDB database. In the Cloud, the services use MongoDB Atlas, a secure, highly-available, and scalable cloud-hosted MongoDB service. Cloud-based databases, like Atlas, are often referred to as Database as a Service (DBaaS). Atlas is a Cloud-based alternative to traditional on-premise databases, as well as equivalent CSP-based solutions, such as Amazon DynamoDB, GCP Cloud Bigtable, and Azure Cosmos DB.

Atlas is an example of a SaaS who offer a single service or small set of closely related services, as an alternative to the big CSP’s equivalent services. Similar providers in this category include CloudAMQP (RabbitMQ as a Service), ClearDB (MySQL DBaaS), Akamai (Content Delivery Network), and Oracle Database Cloud Service (Oracle Database, RAC, and Exadata as a Service). Many of these providers, such as Atlas, are themselves hosted on AWS or other CSPs.

There are three pricing levels for MongoDB Atlas: Free, Essential, and Professional. To follow along with this post, the Free level is sufficient. According to MongoDB, with the Free account level, you get 512 MB of storage with shared RAM, a highly-available 3-node replica set, end-to-end encryption, secure authentication, fully managed upgrades, monitoring and alerts, and a management API. Atlas provides the ability to upgrade your account and CSP specifics at any time.

Once you register for an Atlas account, you will be able to log into Atlas, set up your users, whitelist your IP addresses for security, and obtain necessary connection information. You will need this connection information in the next section to configure the Azure API Apps.


With the Free Atlas tier, you can view detailed Metrics about database cluster activity. However, with the free tier, you do not get access to Real-Time data insights or the ability to use the Data Explorer to view your data through the Atlas UI.


Azure API Apps

The example application’s API consists of two RESTful microservices built with C#, the RestaurantMenu service and RestaurantOrder service. Both services are deployed as Azure API Apps. API Apps is a fully-managed platform. Azure performs OS patching, capacity provisioning, server management, and load balancing.

Microsoft Visual Studio has done an excellent job providing Extensions to make cloud integration a breeze. I will be using Visual Studio Tools for Azure in this post. Similar to how you create a Publish Profile for deploying applications to Internet Information Services (IIS), you create a Publish Profile for Azure App Services. Using the step-by-step user interface, you create a Microsft Azure App Service Web Deploy Publish Profile for each service. To create a new Profile, choose the Microsoft Azure App Service Target.


You must be connected to your Azure account to create the Publish Profile. Give the service an App Name, choose your Subscription, and select or create a Resource Group and an App Service Plan.


The App Service Plan defines the Location and Size for your API App container; these will determine the cost of the compute. I suggest putting the two API Apps and the Web App in the same location, in this case, East US.


The Publish Profile is now available for deploying the services to Azure. No command line interaction is required. The services can be built and published to Azure with a single click from within Visual Studio.


Configuration Management

Azure App Services is highly configurable. For example, each API App requires a different configuration, in each environment, to connect to different instances of MongoDB Atlas databases. For security, sensitive Atlas credentials are not stored in the source code. The Atlas URL and sensitive credentials are stored in App Settings on Azure. For this post, the settings were input directly into the Azure UI, as shown below. You will need to input your own Atlas URL and credentials.

The compiled C# services expect certain environment variables to be present at runtime to connect to MongoDB Atlas. These are provided through Azure’s App Settings. Access to the App Settings in Azure should be tightly controlled through Azure AD and fine-grained Azure Role-Based Access Control (RBAC) service.



If you want to deploy the application from this post to Azure, there is one code change you will need to make to each service, which deals with Cross-Origin Resource Sharing (CORS). The services are currently configured to only accept traffic from my temporary Angular UI App Service’s URL. You will need to adjust the CORS configuration in the \App_Start\WebApiConfig.cs file in each service, to match your own App Service’s new URL.


Angular UI Web App

The Angular UI application will be deployed as an Azure Web App, one of four types of Azure App Services, mentioned previously. According to Microsoft, Web Apps allow Developers to program in their favorite languages, including .NET, Java, Node.js, PHP, and Python on Windows or .NET Core, Node.js, PHP or Ruby on Linux. Web Apps is a fully-managed platform. Azure performs OS patching, capacity provisioning, server management, and load balancing.

Using the Azure Portal, setting up a new Web App for the Angular UI is simple.


Provide an App Name, Subscription, Resource Group, OS Type, and select whether or not you want Application Insights enabled for the Web App.


Although an amazing IDE for web development, WebStorm lacks some of the direct integrations with Azure, AWS, and Google, available with other IDE’s, like Visual Studio. Since the Angular application was developed in WebStorm on Mac, we will take advantage of Azure App Service’s Continuous Deployment feature.

Azure Web Apps can be deployed automatically from most common source code management platforms, including Visual Studio Team Services (VSTS), GitHub, Bitbucket, OneDrive, and local Git repositories.


For this post, I chose GitHub. To configure deployment from GitHub, select the GitHub Account, Organization, Project, and Branch from which Azure will deploy the Angular Web App.


Configuring GitHub in the Azure Portal, Azure becomes an Authorized OAuth App on the GitHub account. Azure creates a Webhook, which fires each time files are pushed (git push) to the dist branch of the GitHub project’s repository.


Using the ng build --dev --env=prod command, the Angular UI application must be first transpiled from TypeScript to JavaScript and bundled for deployment. The ng build command can be run from within WebStorm or from the command line.


The the --env=prod flag ensures that the Production environment configuration, containing the correct Azure API endpoints, issued transpiled into the build. This configuration is stored in the \src\environments\ file, shown below. You will need to update these two endpoints to your own endpoints from the two API Apps you previously deployed to Azure.


Optionally, the code should be optimized for Production, by replacing the --dev flag with the --prod flag. Amongst other optimizations, the Production version of the code is uglified using UglifyJS. Note the difference in the build files shown below for Production, as compared to files above for Development.


Since I chose GitHub for deployment to Azure, I used Git to manually push the local build files to the dist branch on GitHub.


Every time the webhook fires, Azure pulls and deploys the new build, overwriting the previously deployed version, as shown below.


To stage new code and not immediately overwrite running code, Azure has a feature called Deployment slots. According to Microsoft, Deployment slots allow Developers to deploy different versions of Web Apps to different URLs. You can test a certain version and then swap content and configuration between slots. This is likely how you would eventually deploy your code to Production.

Up and Running

Below, the three Azure App Services are shown in the Azure Portal, successfully deployed and running. Note their Status, App Type, Location, and Subscription.


Before exploring the deployed UI, the two Azure API Apps should be tested using Postman. Once the API is confirmed to be working properly, populated by making an HTTP Post request to the menuitems API, the RestaurantOrderService Azure API Service. When the HTTP Post request is made, the RestaurantOrderService stores a set of menu items in the RestaurantMenu Atlas MongoDB database, in the menus collection.


The Angular UI, the RestaurantWeb Azure Web App, is viewed by using the URL provided in the Web App’s Overview tab. The menu items displayed in the drop-down are supplied by an HTTP GET request to the menuitems API, provided by the RestaurantMenuService Azure API Service.


Your order is placed through an HTTP Post request to the orders API, the RestaurantOrderService Azure API Service. The RestaurantOrderService stores the order in the RestaurantOrder Atlas MongoDB database, in the orders collection. The order details are returned in the response body and displayed in the UI.


Once you have the development version of the application successfully up and running on Atlas and Azure, you can start to configure, test, and deploy additional application versions, as App Services, into higher Azure environments, such as Test, Performance, and eventually, Production.


Azure provides in-depth monitoring and performance analytics capabilities for your deployed applications with services like Application Insights. With Azure’s monitoring resources, you can monitor the live performance of your application and set up alerts for application errors and performance issues. Real-time monitoring useful when conducting performance tests. Developers can analyze response time of each API method and optimize the application, Azure configuration, and MongoDB databases, before deploying to Production.



This post demonstrated how the Cloud has shifted application development to a Cloud-first model. Future posts will demonstrate how an application, such as the app featured in this post, is secured, and how it is continuously built, tested, and deployed, using DevOps practices.

All opinions in this post are my own, and not necessarily the views of my current or past employers or their clients.

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Scaffold a RESTful API with Yeoman, Node, Restify, and MongoDB

Using Yeoman, scaffold a basic RESTful CRUD API service, based on Node, Restify, and MongoDB.



NOTE: Generator updated on 11-13-2016 to v0.2.1.

Yeoman generators reduce the repetitive coding of boilerplate functionality and ensure consistency between full-stack JavaScript projects. For several recent Node.js projects, I created the generator-node-restify-mongodb Yeoman generator. This Yeoman generator scaffolds a basic RESTful CRUD API service, a Node application, based on Node.js, Restify, and MongoDB.

According to their website, Restify, used most notably by Netflix, borrows heavily from Express. However, while Express is targeted at browser applications, with templating and rendering, Restify is keenly focused on building API services that are maintainable and observable.

Along with Node, Restify, and MongoDB, theNode application’s scaffolded by the Node-Restify-MongoDB Generator, also implements Bunyan, which includes DTrace, Jasmine, using jasmine-nodeMongoose, and Grunt.

Portions of the scaffolded Node application’s file structure and code are derived from what I consider the best parts of several different projects, including generator-express, generator-restify-mongo, and generator-restify.


To begin, install Yeoman and the generator-node-restify-mongodb using npm. The generator assumes you have pre-installed Node and MongoDB.

npm install -g yo
npm install -g generator-node-restify-mongodb

Then, generate the new project.

mkdir node-restify-mongodb
cd $_
yo node-restify-mongodb

Yeoman scaffolds the application, creating the directory structure, copying required files, and running ‘npm install’ to load the npm package dependencies.



Using the Generated Application

Next, import the supplied set of sample widget documents into the local development instance of MongoDB from the supplied ‘data/widgets.json’ file.

NODE_ENV=development grunt mongoimport --verbose

Similar to Yeoman’s Express Generator, this application contains configuration for three typical environments: ‘Development’ (default), ‘Test’, and ‘Production’. If you want to import the sample widget documents into your Test or Production instances of MongoDB, first change the ‘NODE_ENV’ environment variable value.

NODE_ENV=production grunt mongoimport --verbose

To start the application in a new terminal window, use the following command.

npm start

The output should be similar to the example, below.


To test the application, using jshint and the jasmine-node module, the sample documents must be imported into MongoDB and the application must be running (see above). To test the application, open a separate terminal window, and use the following command.

npm test

The project contains a set of jasmine-node tests, split between the ‘/widgets’ and the ‘/utils’ endpoints. If the application is running correctly, you should see the following output from the tests.


Similarly, the following command displays a code coverage report, using the grunt, mocha, istanbul, and grunt-mocha-istanbul node modules.

grunt coverage

Grunt uses the grunt-mocha-istanbul module to execute the same set of jasmine-node tests as shown above. Based on those tests, the application’s code coverage (statement, line, function, and branch coverage) is displayed.


You may test the running application, directly, by cURLing the ‘/widgets’ endpoints.

curl -X GET -H "Accept: application/json" "http://localhost:3000/widgets"

For more legible output, try prettyjson.

npm install -g prettyjson
curl -X GET -H "Accept: application/json" "http://localhost:3000/widgets" --silent | prettyjson
curl -X GET -H "Accept: application/json" "http://localhost:3000/widgets/SVHXPAWEOD" --silent | prettyjson

The JSON-formatted response body from the HTTP GET requests should look similar to the output, below.


A much better RESTful API testing solution is Postman. Postman provides the ability to individually configure each environment and abstract that environment-specific configuration, such as host and port, from the actual HTTP requests.


Continuous Integration

As part of being published to both the npmjs and Yeoman registries, the generator-node-restify-mongodb generator is continuously integrated on Travis CI. This should provide an addition level of confidence to the generator’s end-users. Currently, Travis CI tests the generator against Node.js v4, v5, and v6, as well as IO.js. Older versions of Node.js may have compatibility issues with the application.


Additionally, Travis CI feeds test results to Coveralls, which displays the generator’s code coverage. Note the code coverage, shown below, is reported for the yeoman generator, not the generator’s scaffolded application. The scaffolded application’s coverage is shown above.


Application Details

API Endpoints

The scaffolded application includes the following endpoints.

# widget resources
var PATH = '/widgets';
server.get({path: PATH, version: VERSION}, findDocuments);
server.get({path: PATH + '/:product_id', version: VERSION}, findOneDocument);{path: PATH, version: VERSION}, createDocument);
server.put({path: PATH, version: VERSION}, updateDocument);
server.del({path: PATH + '/:product_id', version: VERSION}, deleteDocument);

# utility resources
var PATH = '/utils';
server.get({path: PATH + '/ping', version: VERSION}, ping);
server.get({path: PATH + '/health', version: VERSION}, health);
server.get({path: PATH + '/info', version: VERSION}, information);
server.get({path: PATH + '/config', version: VERSION}, configuraton);
server.get({path: PATH + '/env', version: VERSION}, environment);

The Widget

The Widget is the basic document object used throughout the application. It is used, primarily, to demonstrate Mongoose’s Model and Schema. The Widget object contains the following fields, as shown in the sample widget, below.

  "product_id": "4OZNPBMIDR",
  "name": "Fapster",
  "color": "Orange",
  "size": "Medium",
  "price": "29.99",
  "inventory": 5


Use the mongo shell to access the application’s MongoDB instance and display the imported sample documents.

 > show dbs
 > use node-restify-mongodb-development
 > show tables
 > db.widgets.find()

The imported sample documents should be displayed, as shown below.


Environmental Variables

The scaffolded application relies on several environment variables to determine its environment-specific runtime configuration. If these environment variables are present, the application defaults to using the Development environment values, as shown below, in the application’s ‘config/config.js’ file.

var NODE_ENV   = process.env.NODE_ENV   || 'development';
var NODE_HOST  = process.env.NODE_HOST  || '';
var NODE_PORT  = process.env.NODE_PORT  || 3000;
var MONGO_HOST = process.env.MONGO_HOST || '';
var MONGO_PORT = process.env.MONGO_PORT || 27017;
var LOG_LEVEL  = process.env.LOG_LEVEL  || 'info';
var APP_NAME   = 'node-restify-mongodb-';

Future Project TODOs

Future project enhancements include the following:

  • Add filtering, sorting, field selection and paging
  • Add basic HATEOAS-based response features
  • Add authentication and authorization to production MongoDB instance
  • Convert from out-dated jasmine-node to Jasmine?

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Continuous Integration and Delivery of Microservices using Jenkins CI, Docker Machine, and Docker Compose

Continuously integrate and deploy and test a RestExpress microservices-based, multi-container, Java EE application to a virtual test environment, using Docker, Docker Hub, Docker Machine, Docker Compose, Jenkins CI, Maven, and VirtualBox.

Docker Machine with Ambassador


In the last post, we learned how to use Jenkins CI, Maven, and Docker Compose to take a set of microservices all the way from source control on GitHub, to a fully tested and running set of integrated Docker containers. We built the microservices, Docker images, and Docker containers. We deployed the containers directly onto the Jenkins CI Server machine. Finally, we performed integration tests to ensure the services were functioning as expected, within the containers.

In a more mature continuous delivery model, we would have deployed the running containers to a fresh ‘production-like’ environment to be more accurately tested, not the Jenkins CI Server host machine. In this post, we will learn how to use the recently released Docker Machine to create a fresh test environment in which to build and host our project’s ten Docker containers. We will couple Docker Machine with Oracle’s VirtualBoxJenkins CI, and Docker Compose to automatically build and test the services within their containers, within the virtual ‘test’ environment.

Update: All code for this post is available on GitHub, release version v2.1.0 on the ‘master’ branch (after running git clone …, run a ‘git checkout tags/v2.1.0’ command).

Docker Machine

If you recall in the last post, after compiling and packaging the microservices, Jenkins was used to deploy the build artifacts to the Virtual-Vehicles Docker GitHub project, as shown below.

Build and Deploy Results

We then used Jenkins, with the Docker CLI and the Docker Compose CLI, to automatically build and test the images and containers. This step will not change, however first we will use Docker Machine to automatically build a test environment, in which we will build the Docker images and containers.

Docker Machine with Ambassador

I’ve copied and modified the second Jenkins job we used in the last post, as shown below. The new job is titled, ‘Virtual-Vehicles_Docker_Machine’. This will replace the previous job, ‘Virtual-Vehicles_Docker_Compose’.

Jenkins CI Jobs Machine

The first step in the new Jenkins job is to clone the Virtual-Vehicles Docker GitHub repository.

Jenkins CI Machine Config 1

Next, Jenkins run a bash script to automatically build the test VM with Docker Machine, build the Docker images and containers with Docker Compose within the new VM, and finally test the services.

Jenkins CI Machine Config 2

The bash script executed by Jenkins contains the following commands:

# optional: record current versions of docker apps with each build
docker -v && docker-compose -v && docker-machine -v

# set-up: clean up any previous machine failures
docker-machine stop test || echo "nothing to stop" && \
docker-machine rm test   || echo "nothing to remove"

# use docker-machine to create and configure 'test' environment
# add a -D (debug) if having issues
docker-machine create --driver virtualbox test
eval "$(docker-machine env test)"

# use docker-compose to pull and build new images and containers
docker-compose -p jenkins up -d

# optional: list machines, images, and containers
docker-machine ls && docker images && docker ps -a

# wait for containers to fully start before tests fire up
sleep 30

# test the services
sh $(docker-machine ip test)

# tear down: stop and remove 'test' environment
docker-machine stop test && docker-machine rm test

As the above script shows, first Jenkins uses the Docker Machine CLI to build and activate the ‘test’ virtual machine, using the VirtualBox driver. As of docker-machine version 0.3.0, the VirtualBox driver requires at least VirtualBox 4.3.28 to be installed.

docker-machine create --driver virtualbox test
eval "$(docker-machine env test)"

Once this step is complete you will have the following VirtualBox VM created, running, and active.

NAME   ACTIVE   DRIVER       STATE     URL                         SWARM
test   *        virtualbox   Running   tcp://

Next, Jenkins uses the Docker Compose CLI to execute the project’s Docker Compose YAML file.

docker-compose -p jenkins up -d

The YAML file directs Docker Compose to pull and build the required Docker images, and to build and configure the Docker containers.

# title:       Docker Compose YAML file for Virtual-Vehicles Project
# author:      Gary A. Stafford (
# url:  
# description: Pulls (5) images, builds (5) images, and builds (11) containers,
#              for the Virtual-Vehicles Java microservices example REST API
# to run:      docker-compose -p <your_project_name_here> up -d

  image: hopsoft/graphite-statsd:latest
   - "8500:80"

  image: mongo:latest

  image: mongo:latest

  image: mongo:latest

  image: mongo:latest

  build: authentication/
   - graphite
   - mongoAuthentication
   - "ambassador:nginx"
   - "8587"

  build: valet/
   - graphite
   - mongoValet
   - "ambassador:nginx"
   - "8585"

  build: maintenance/
   - graphite
   - mongoMaintenance
   - "ambassador:nginx"
   - "8583"

  build: vehicle/
   - graphite
   - mongoVehicle
   - "ambassador:nginx"
   - "8581"

  build: nginx/
   - "80:80"
   - "ambassador:vehicle"
   - "ambassador:valet"
   - "ambassador:authentication"
   - "ambassador:maintenance"

  image: cpuguy83/docker-grand-ambassador
   - "/var/run/docker.sock:/var/run/docker.sock"
  command: "-name jenkins_nginx_1 -name jenkins_authentication_1 -name jenkins_maintenance_1 -name jenkins_valet_1 -name jenkins_vehicle_1"

Running the docker-compose.yaml file, will pull these (5) Docker Hub images:

REPOSITORY                           TAG          IMAGE ID
==========                           ===          ========
java                                 8u45-jdk     1f80eb0f8128
nginx                                latest       319d2015d149
mongo                                latest       66b43e3cae49
hopsoft/graphite-statsd              latest       b03e373279e8
cpuguy83/docker-grand-ambassador     latest       c635b1699f78

And, build these (5) Docker images from Dockerfiles:

REPOSITORY                  TAG          IMAGE ID
==========                  ===          ========
jenkins_nginx               latest       0b53a9adb296
jenkins_vehicle             latest       d80f79e605f4
jenkins_valet               latest       cbe8bdf909b8
jenkins_maintenance         latest       15b8a94c00f4
jenkins_authentication      latest       ef0345369079

And, build these (11) Docker containers from corresponding image:

CONTAINER ID     IMAGE                                NAME
============     =====                                ====
17992acc6542     jenkins_nginx                        jenkins_nginx_1
bcbb2a4b1a7d     jenkins_vehicle                      jenkins_vehicle_1
4ac1ac69f230     mongo:latest                         jenkins_mongoVehicle_1
bcc8b9454103     jenkins_valet                        jenkins_valet_1
7c1794ca7b8c     jenkins_maintenance                  jenkins_maintenance_1
2d0e117fa5fb     jenkins_authentication               jenkins_authentication_1
d9146a1b1d89     hopsoft/graphite-statsd:latest       jenkins_graphite_1
56b34cee9cf3     cpuguy83/docker-grand-ambassador     jenkins_ambassador_1
a72199d51851     mongo:latest                         jenkins_mongoAuthentication_1
307cb2c01cc4     mongo:latest                         jenkins_mongoMaintenance_1
4e0807431479     mongo:latest                         jenkins_mongoValet_1

Since we are connected to the brand new Docker Machine ‘test’ VM, there are no locally cached Docker images. All images required to build the containers must be pulled from Docker Hub. The build time will be 3-4x as long as the last post’s build, which used the cached Docker images on the Jenkins CI machine.

Integration Testing

As in the last post, once the containers are built and configured, we run a series of expanded integration tests to confirm the containers and services are working. One difference, this time we will pass a parameter to the test bash script file:

sh $(docker-machine ip test)

The parameter is the hostname used in the test’s RESTful service calls. The parameter, $(docker-machine ip test), is translated to the IP address of the ‘test’ VM. In our example, If a parameter is not provided, the test script’s hostname variable will use the default value of localhost, ‘hostname=${1-'localhost'}‘.

Another change since the last post, the project now uses the open source version of Nginx, the free, open-source, high-performance HTTP server and reverse proxy, as a pseudo-API gateway. Instead calling each microservice directly, using their individual ports (i.e. port 8581 for the Vehicle microservice), all traffic is sent through Nginx on default http port 80, for example:

Internal traffic between the microservices and MongoDB, and between the microservices and Graphite is still direct, using Docker container linking. Traffic between the microservices and Nginx, in both directions, is handled by an ambassador container, a common pattern. Nginx acts as a reverse proxy for the microservices. Using Nginx brings us closer to a truer production-like experience for testing the services.


# title:          Virtual-Vehicles Project Integration Tests
# author:         Gary A. Stafford (
# url:    
# description:    Performs integration tests on the Virtual-Vehicles
#                 microservices
# to run:         sh
# docker-machine: sh $(docker-machine ip test)

echo --- Integration Tests ---

hostname=${1-'localhost'} # use input param or default to localhost
application="Test API Client $(date +%s)" # randomized
secret="$(date +%s | sha256sum | base64 | head -c 15)" # randomized

echo hostname: ${hostname}
echo application: ${application}
echo secret: ${secret}
echo make: ${make}
echo model: ${model}

### TESTS ###
echo "TEST: GET request should return 'true' in the response body"
echo ${url}
curl -X GET -H 'Accept: application/json; charset=UTF-8' \
--url "${url}" \
| grep true > /dev/null
[ "$?" -ne 0 ] && echo "RESULT: fail" && exit 1
echo "RESULT: pass"

echo "TEST: POST request should return a new client in the response body with an 'id'"
echo ${url}
curl -X POST -H "Cache-Control: no-cache" -d "{
    \"application\": \"${application}\",
    \"secret\": \"${secret}\"
}" --url "${url}" \
| grep '"id":"[a-zA-Z0-9]\{24\}"' > /dev/null
[ "$?" -ne 0 ] && echo "RESULT: fail" && exit 1
echo "RESULT: pass"

echo "SETUP: Get the new client's apiKey for next test"
echo ${url}
apiKey=$(curl -X POST -H "Cache-Control: no-cache" -d "{
    \"application\": \"${application}\",
    \"secret\": \"${secret}\"
}" --url "${url}" \
| grep -o '"apiKey":"[a-zA-Z0-9]\{24\}"' \
| grep -o '[a-zA-Z0-9]\{24\}' \
| sed -e 's/^"//'  -e 's/"$//')
echo apiKey: ${apiKey}

echo "TEST: GET request should return a new jwt in the response body"
echo ${url}
curl -X GET -H "Cache-Control: no-cache" \
--url "${url}" \
| grep '[a-zA-Z0-9_-]\{1,\}\.[a-zA-Z0-9_-]\{1,\}\.[a-zA-Z0-9_-]\{1,\}' > /dev/null
[ "$?" -ne 0 ] && echo "RESULT: fail" && exit 1
echo "RESULT: pass"

echo "SETUP: Get a new jwt using the new client for the next test"
echo ${url}
jwt=$(curl -X GET -H "Cache-Control: no-cache" \
--url "${url}" \
| grep '[a-zA-Z0-9_-]\{1,\}\.[a-zA-Z0-9_-]\{1,\}\.[a-zA-Z0-9_-]\{1,\}' \
| sed -e 's/^"//'  -e 's/"$//')
echo jwt: ${jwt}

echo "TEST: POST request should return a new vehicle in the response body with an 'id'"
echo ${url}
curl -X POST -H "Cache-Control: no-cache" \
-H "Authorization: Bearer ${jwt}" \
-d "{
    \"year\": 2015,
    \"make\": \"${make}\",
    \"model\": \"${model}\",
    \"color\": \"White\",
    \"type\": \"Sedan\",
    \"mileage\": 250
}" --url "${url}" \
| grep '"id":"[a-zA-Z0-9]\{24\}"' > /dev/null
[ "$?" -ne 0 ] && echo "RESULT: fail" && exit 1
echo "RESULT: pass"

echo "SETUP: Get id from new vehicle for the next test"
echo ${url}
id=$(curl -X GET -H "Cache-Control: no-cache" \
-H "Authorization: Bearer ${jwt}" \
--url "${url}" \
| grep '"id":"[a-zA-Z0-9]\{24\}"' \
| grep -o '[a-zA-Z0-9]\{24\}' \
| tail -1 \
| sed -e 's/^"//'  -e 's/"$//')
echo vehicle id: ${id}

echo "TEST: GET request should return a vehicle in the response body with the requested 'id'"
echo ${url}
curl -X GET -H "Cache-Control: no-cache" \
-H "Authorization: Bearer ${jwt}" \
--url "${url}" \
| grep '"id":"[a-zA-Z0-9]\{24\}"' > /dev/null
[ "$?" -ne 0 ] && echo "RESULT: fail" && exit 1
echo "RESULT: pass"

echo "TEST: POST request should return a new maintenance record in the response body with an 'id'"
echo ${url}
curl -X POST -H "Cache-Control: no-cache" \
-H "Authorization: Bearer ${jwt}" \
-d "{
    \"vehicleId\": \"${id}\",
    \"serviceDateTime\": \"2015-27-00T15:00:00.400Z\",
    \"mileage\": 1000,
    \"type\": \"Test Maintenance\",
    \"notes\": \"This is a test notes.\"
}" --url "${url}" \
| grep '"id":"[a-zA-Z0-9]\{24\}"' > /dev/null
[ "$?" -ne 0 ] && echo "RESULT: fail" && exit 1
echo "RESULT: pass"

echo "TEST: POST request should return a new valet transaction in the response body with an 'id'"
echo ${url}
curl -X POST -H "Cache-Control: no-cache" \
-H "Authorization: Bearer ${jwt}" \
-d "{
    \"vehicleId\": \"${id}\",
    \"dateTimeIn\": \"2015-27-00T15:00:00.400Z\",
    \"parkingLot\": \"Test Parking Ramp\",
    \"parkingSpot\": 10,
    \"notes\": \"This is a test notes.\"
}" --url "${url}" \
| grep '"id":"[a-zA-Z0-9]\{24\}"' > /dev/null
[ "$?" -ne 0 ] && echo "RESULT: fail" && exit 1
echo "RESULT: pass"

Tear Down

In true continuous integration fashion, once the integration tests have completed, we tear down the project by removing the VirtualBox ‘test’ VM. This also removed all images and containers.

docker-machine stop test && \
docker-machine rm test

Jenkins CI Console Output

Below is an abridged sample of what the Jenkins CI console output will look like from a successful ‘build’.

Started by user anonymous
Building in workspace /var/lib/jenkins/jobs/Virtual-Vehicles_Docker_Machine/workspace
> git rev-parse --is-inside-work-tree # timeout=10
Fetching changes from the remote Git repository
> git config remote.origin.url # timeout=10
Fetching upstream changes from
> git --version # timeout=10
using GIT_SSH to set credentials
using .gitcredentials to set credentials
> git config --local credential.helper store --file=/tmp/git7588068314920923143.credentials # timeout=10
> git -c core.askpass=true fetch --tags --progress +refs/heads/*:refs/remotes/origin/*
> git config --local --remove-section credential # timeout=10
> git rev-parse refs/remotes/origin/master^{commit} # timeout=10
> git rev-parse refs/remotes/origin/origin/master^{commit} # timeout=10
Checking out Revision f473249f0f70290b75cb320909af1f57cdaf2aa5 (refs/remotes/origin/master)
> git config core.sparsecheckout # timeout=10
> git checkout -f f473249f0f70290b75cb320909af1f57cdaf2aa5
> git rev-list f473249f0f70290b75cb320909af1f57cdaf2aa5 # timeout=10
[workspace] $ /bin/sh -xe /tmp/

+ docker -v
Docker version 1.7.0, build 0baf609
+ docker-compose -v
docker-compose version: 1.3.1
CPython version: 2.7.9
OpenSSL version: OpenSSL 1.0.1e 11 Feb 2013
+ docker-machine -v
docker-machine version 0.3.0 (0a251fe)

+ docker-machine stop test
+ docker-machine rm test
Successfully removed test

+ docker-machine create --driver virtualbox test
Creating VirtualBox VM...
Creating SSH key...
Starting VirtualBox VM...
Starting VM...
To see how to connect Docker to this machine, run: docker-machine env test
+ docker-machine env test
+ eval export DOCKER_TLS_VERIFY="1"
export DOCKER_HOST="tcp://"
export DOCKER_CERT_PATH="/var/lib/jenkins/.docker/machine/machines/test"
# Run this command to configure your shell:
# eval "$(docker-machine env test)"
+ export DOCKER_HOST=tcp://
+ export DOCKER_CERT_PATH=/var/lib/jenkins/.docker/machine/machines/test
+ docker-compose -p jenkins up -d
Pulling mongoValet (mongo:latest)...
latest: Pulling from mongo

...Abridged output...

+ docker-machine ls
NAME   ACTIVE   DRIVER       STATE     URL                         SWARM
test   *        virtualbox   Running   tcp://
+ docker images
REPOSITORY                         TAG                 IMAGE ID            CREATED             VIRTUAL SIZE
jenkins_vehicle                    latest              fdd7f9d02ff7        2 seconds ago       837.1 MB
jenkins_valet                      latest              8a592e0fe69a        4 seconds ago       837.1 MB
jenkins_maintenance                latest              5a4a44e136e5        5 seconds ago       837.1 MB
jenkins_authentication             latest              e521e067a701        7 seconds ago       838.7 MB
jenkins_nginx                      latest              085d183df8b4        25 minutes ago      132.8 MB
java                               8u45-jdk            1f80eb0f8128        12 days ago         816.4 MB
nginx                              latest              319d2015d149        12 days ago         132.8 MB
mongo                              latest              66b43e3cae49        12 days ago         260.8 MB
hopsoft/graphite-statsd            latest              b03e373279e8        4 weeks ago         740 MB
cpuguy83/docker-grand-ambassador   latest              c635b1699f78        5 months ago        525.7 MB

+ docker ps -a
CONTAINER ID        IMAGE                              COMMAND                CREATED             STATUS              PORTS                                      NAMES
4ea39fa187bf        jenkins_vehicle                    "java -classpath .:c   2 seconds ago       Up 1 seconds        8581/tcp                                   jenkins_vehicle_1
b248a836546b        mongo:latest                       "/ mong   3 seconds ago       Up 3 seconds        27017/tcp                                  jenkins_mongoVehicle_1
0c94e6409afc        jenkins_valet                      "java -classpath .:c   4 seconds ago       Up 3 seconds        8585/tcp                                   jenkins_valet_1
657f8432004b        jenkins_maintenance                "java -classpath .:c   5 seconds ago       Up 5 seconds        8583/tcp                                   jenkins_maintenance_1
8ff6de1208e3        jenkins_authentication             "java -classpath .:c   7 seconds ago       Up 6 seconds        8587/tcp                                   jenkins_authentication_1
c799d5f34a1c        hopsoft/graphite-statsd:latest     "/sbin/my_init"        12 minutes ago      Up 12 minutes       2003/tcp, 8125/udp,>80/tcp   jenkins_graphite_1
040872881b25        jenkins_nginx                      "nginx -g 'daemon of   25 minutes ago      Up 25 minutes>80/tcp, 443/tcp                jenkins_nginx_1
c6a2dc726abc        mongo:latest                       "/ mong   26 minutes ago      Up 26 minutes       27017/tcp                                  jenkins_mongoAuthentication_1
db22a44239f4        mongo:latest                       "/ mong   26 minutes ago      Up 26 minutes       27017/tcp                                  jenkins_mongoMaintenance_1
d5fd655474ba        cpuguy83/docker-grand-ambassador   "/usr/bin/grand-amba   26 minutes ago      Up 26 minutes                                                  jenkins_ambassador_1
2b46bd6f8cfb        mongo:latest                       "/ mong   31 minutes ago      Up 31 minutes       27017/tcp                                  jenkins_mongoValet_1

+ sleep 30

+ docker-machine ip test
+ sh

--- Integration Tests ---

application: Test API Client 1435585062
make: Test
model: Foo

TEST: GET request should return 'true' in the response body
% Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
Dload  Upload   Total   Spent    Left  Speed

0     0    0     0    0     0      0      0 --:--:-- --:--:-- --:--:--     0
100     4    0     4    0     0     26      0 --:--:-- --:--:-- --:--:--    25
100     4    0     4    0     0     26      0 --:--:-- --:--:-- --:--:--    25
RESULT: pass

TEST: POST request should return a new client in the response body with an 'id'
% Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
Dload  Upload   Total   Spent    Left  Speed

0     0    0     0    0     0      0      0 --:--:-- --:--:-- --:--:--     0
100   399    0   315  100    84    847    225 --:--:-- --:--:-- --:--:--   849
RESULT: pass

SETUP: Get the new client's apiKey for next test
% Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
Dload  Upload   Total   Spent    Left  Speed

0     0    0     0    0     0      0      0 --:--:-- --:--:-- --:--:--     0
100   399    0   315  100    84  20482   5461 --:--:-- --:--:-- --:--:-- 21000
apiKey: sv1CA9NdhmXh72NrGKBN3Abb

TEST: GET request should return a new jwt in the response body
% Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
Dload  Upload   Total   Spent    Left  Speed

0     0    0     0    0     0      0      0 --:--:-- --:--:-- --:--:--     0
100   222    0   222    0     0    686      0 --:--:-- --:--:-- --:--:--   687
RESULT: pass

SETUP: Get a new jwt using the new client for the next test
% Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
Dload  Upload   Total   Spent    Left  Speed

0     0    0     0    0     0      0      0 --:--:-- --:--:-- --:--:--     0
100   222    0   222    0     0  16843      0 --:--:-- --:--:-- --:--:-- 17076
jwt: eyJ0eXAiOiJKV1QiLCJhbGciOiJIUzI1NiJ9.eyJpc3MiOiJhcGkudmlydHVhbC12ZWhpY2xlcy5jb20iLCJhcGlLZXkiOiJzdjFDQTlOZGhtWGg3Mk5yR0tCTjNBYmIiLCJleHAiOjE0MzU2MjEwNjMsImFpdCI6MTQzNTU4NTA2M30.WVlhIhUcTz6bt3iMVr6MWCPIDd6P0aDZHl_iUd6AgrM

TEST: POST request should return a new vehicle in the response body with an 'id'
% Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
Dload  Upload   Total   Spent    Left  Speed

0     0    0     0    0     0      0      0 --:--:-- --:--:-- --:--:--     0
100   123    0     0  100   123      0    612 --:--:-- --:--:-- --:--:--   611
100   419    0   296  100   123    649    270 --:--:-- --:--:-- --:--:--   649
RESULT: pass

SETUP: Get id from new vehicle for the next test|model::Foo&limit=1
% Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
Dload  Upload   Total   Spent    Left  Speed

0     0    0     0    0     0      0      0 --:--:-- --:--:-- --:--:--     0
100   377    0   377    0     0   5564      0 --:--:-- --:--:-- --:--:--  5626
vehicle id: 55914a28e4b04658471dc03a

TEST: GET request should return a vehicle in the response body with the requested 'id'
% Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
Dload  Upload   Total   Spent    Left  Speed

0     0    0     0    0     0      0      0 --:--:-- --:--:-- --:--:--     0
100   296    0   296    0     0   7051      0 --:--:-- --:--:-- --:--:--  7219
RESULT: pass

TEST: POST request should return a new maintenance record in the response body with an 'id'
% Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
Dload  Upload   Total   Spent    Left  Speed

0     0    0     0    0     0      0      0 --:--:-- --:--:-- --:--:--     0
100   565    0   376  100   189    506    254 --:--:-- --:--:-- --:--:--   506
100   565    0   376  100   189    506    254 --:--:-- --:--:-- --:--:--   506
RESULT: pass

TEST: POST request should return a new valet transaction in the response body with an 'id'
% Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
Dload  Upload   Total   Spent    Left  Speed

0     0    0     0    0     0      0      0 --:--:-- --:--:-- --:--:--     0
100   561    0   368  100   193    514    269 --:--:-- --:--:-- --:--:--   514
RESULT: pass

+ docker-machine stop test
+ docker-machine rm test
Successfully removed test

Finished: SUCCESS

Graphite and Statsd

If you’ve chose to build the Virtual-Vehicles Docker project outside of Jenkins CI, then in addition running the test script and using applications like Postman to test the Virtual-Vehicles RESTful API, you may also use Graphite and StatsD. RestExpress comes fully configured out of the box with Graphite integration, through the Metrics plugin. The Virtual-Vehicles RESTful API example is configured to use port 8500 to access the Graphite UI. The Virtual-Vehicles RESTful API example uses the hopsoft/graphite-statsd Docker image to build the Graphite/StatsD Docker container.

Graphite Dashboard

The Complete Process

The below diagram show the entire Virtual-Vehicles continuous integration and delivery process, start to finish, using Docker, Docker Hub, Docker Machine, Docker Compose, Jenkins CI, Maven, RestExpress, and VirtualBox.

Docker Machine Full Process

, , , , , , , , , , , , , ,


Continuous Integration and Delivery of Microservices using Jenkins CI, Maven, and Docker Compose

Continuously build, test, package and deploy a microservices-based, multi-container, Java EE application using Jenkins CI, Maven, Docker, and Docker Compose


Previous Posts

In the previous 3-part series, Building a Microservices-based REST API with RestExpress, Java EE, and MongoDB, we developed a set of Java EE-based microservices, which formed the Virtual-Vehicles REST API. In Part One of this series, we introduced the concepts of a RESTful API and microservices, using the vehicle-themed Virtual-Vehicles REST API example. In Part Two, we gained a basic understanding of how RestExpress works to build microservices, and discovered how to get the microservices example up and running. Lastly, in Part Three, we explored how to use tools such as Postman, along with the API documentation, to test our microservices.


In this post, we will demonstrate how to use Jenkins CI, Maven, and Docker Compose to take our set of microservices all the way from source control on GitHub, to a fully tested and running set of integrated and orchestrated Docker containers. We will build and test the microservices, Docker images, and Docker containers. We will deploy the containers and perform integration tests to ensure the services are functioning as expected, within the containers. The milestones in our process will be:

  1. Continuous Integration: Using Jenkins CI and Maven, automatically compile, test, and package the individual microservices
  2. Deployment: Using Jenkins, automatically deploy the build artifacts to the new Virtual-Vehicles Docker project
  3. Containerization: Using Jenkins and Docker Compose, automatically build the Docker images and containers from the build artifacts and a set of Dockerfiles
  4. Integration Testing: Using Jenkins, perform automated integration tests on the containerized services
  5. Tear Down: Using Jenkins, automatically stop and remove the containers and images

For brevity, we will deploy the containers directly to the Jenkins CI Server, where they were built. In an upcoming post, I will demonstrate how to use the recently released Docker Machine to host the containers within an isolated VM.

Note: All code for this post is available on GitHub, release version v1.0.0 on the ‘master’ branch (after running git clone …, run a ‘git checkout tags/v1.0.0’ command).

Build the Microservices

In order to host the Virtual-Vehicles microservices, we must first compile the source code and produce build artifacts. In the case of the Virtual-Vehicles example, the build artifacts are a JAR file and at least one environment-specific properties file. In Part Two of our previous series, we compiled and produced JAR files for our microservices from the command line using Maven.

Build and Deploy

To automatically build our Maven-based microservices project in this post, we will use Jenkins CI and the Jenkins Maven Project Plugin. The Virtual-Vehicles microservices are bundled together into what Maven considers a multi-module project, which is defined by a parent POM referring to one or more sub-modules. Using the concept of project inheritance, Jenkins will compile each of the four microservices from the project’s single parent POM file. Note the four modules at the end of the pom.xml below, corresponding to each microservice.

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="" xmlns:xsi="" xsi:schemaLocation="">

    <name>Virtual-Vehicles API</name>
    <description>Virtual-Vehicles API


Below is the view of the four individual Maven modules, within the single Jenkins Maven job.

Maven Modules In Jenkins

Each microservice module contains a Maven POM files. The POM files use the Apache Maven Compiler Plugin to compile code, and the Apache Maven Shade Plugin to create ‘uber-jars’ from the compiled code. The Shade plugin provides the capability to package the artifact in an uber-jar, including its dependencies. This will allow us to independently host the service in its own container, without external dependencies. Lastly, using the Apache Maven Resources Plugin, Maven will copy the environment properties files from the source directory to the ‘target’ directory, which contains the JAR file. To accomplish these Maven tasks, all Jenkins needs to do is a series of Maven life-cycle goals: ‘clean install package validate‘.

Once the code is compiled and packaged into uber-jars, Jenkins uses the Artifact Deployer Plugin to deploy the build artifacts from Jenkins’ workspace to a remote location. In our example, we will copy the artifacts to a second GitHub project, from which we will containerize our microservices.

Shown below are the two Jenkins jobs. The first one compiles, packages, and deploys the build artifacts. The second job containerizes the services, databases, and monitoring application.

Jenkins CI Main Page

Shown below are two screen grabs showing how we clone the Virtual-Vehicles GitHub repository and build the project using the main parent pom.xml file. Building the parent POM, in-turn builds all the microservice modules, using their POM files.

Build and Deploy Config 1

Build and Deploy Config 2

Deploy Build Artifacts

Once we have successfully compiled, tested (if we had unit tests with RestExpress), and packages the build artifacts as uber-jars, we deploy each set of build artifacts to a subfolder within the Virtual-Vehicles Docker GitHub project, using Jenkins’ Artifact Deployer Plugin. Shown below is the deployment configuration for just the Vehicles microservice. This deployment pattern is repeated for each service, within the Jenkins job configuration.

Build and Deploy Config 3

The Jenkins’ Artifact Deployer Plugin also provides the convenient ability to view and to redeploy the artifacts. Below, you see a list of the microservice artifacts deployed to the Docker project by Jenkins.

Build and Deploy Results

Build and Compose the Containers


The second Jenkins job clones the Virtual-Vehicles Docker GitHub repository.

Docker Compose Config 1

The second Jenkins job executes commands from the shell prompt. The first commands use the Docker CLI to removes any existing images and containers, which might have been left over from previous job failures. The second commands use the Docker Compose CLI to execute the project’s Docker Compose YAML file. The YAML file directs Docker Compose to pull and build the required Docker images, and to build and configure the Docker containers.

Docker Compose Config 2

# remove all images and containers from this build
docker ps -a --no-trunc  | grep 'jenkins' \
| awk '{print $1}' | xargs -r --no-run-if-empty docker stop && \
docker ps -a --no-trunc  | grep 'jenkins' \
| awk '{print $1}' | xargs -r --no-run-if-empty docker rm && \
docker images --no-trunc | grep 'jenkins' \
| awk '{print $3}' | xargs -r --no-run-if-empty docker rmi
# set DOCKER_HOST environment variable
export DOCKER_HOST=tcp://localhost:4243

# record installed version of Docker and Maven with each build
mvn --version && \
docker --version && \
docker-compose --version

# use docker-compose to build new images and containers
docker-compose -p jenkins up -d

# list virtual-vehicles related images
docker images | grep 'jenkins' | awk '{print $0}'

# list all containers
docker ps -a | grep 'jenkins\|mongo_\|graphite' | awk '{print $0}'
# title:       Docker Compose YAML file for Virtual-Vehicles Project
# author:      Gary A. Stafford (
# url:  
# description: Builds (4) images, pulls (2) images, and builds (9) containers,
#              for the Virtual-Vehicles Java microservices example REST API
# to run:      docker-compose -p virtualvehicles up -d

  image: hopsoft/graphite-statsd:latest
   - "8481:80"

  image: mongo:latest

  image: mongo:latest

  image: mongo:latest

  image: mongo:latest

  build: authentication/
   - "8587:8587"
   - graphite
   - mongoAuthentication

  build: valet/
   - "8585:8585"
   - graphite
   - mongoValet
   - authentication

  build: maintenance/
   - "8583:8583"
   - graphite
   - mongoMaintenance
   - authentication

  build: vehicle/
   - "8581:8581"
   - graphite
   - mongoVehicle
   - authentication

Running the docker-compose.yaml file, produces the following images:

REPOSITORY                TAG        IMAGE ID
==========                ===        ========
jenkins_vehicle           latest     a6ea4dfe7cf5
jenkins_valet             latest     162d3102d43c
jenkins_maintenance       latest     0b6f530cc968
jenkins_authentication    latest     45b50487155e

And, these containers:

CONTAINER ID     IMAGE                              NAME
============     =====                              ====
2b4d5a918f1f     jenkins_vehicle                    jenkins_vehicle_1
492fbd88d267     mongo:latest                       jenkins_mongoVehicle_1
01f410bb1133     jenkins_valet                      jenkins_valet_1
6a63a664c335     jenkins_maintenance                jenkins_maintenance_1
00babf484cf7     jenkins_authentication             jenkins_authentication_1
548a31034c1e     hopsoft/graphite-statsd:latest     jenkins_graphite_1
cdc18bbb51b4     mongo:latest                       jenkins_mongoAuthentication_1
6be5c0558e92     mongo:latest                       jenkins_mongoMaintenance_1
8b71d50a4b4d     mongo:latest                       jenkins_mongoValet_1

Integration Testing

Once the containers have been successfully built and configured, we run a series of integration tests to confirm the services are up and running. We refer to these tests as integration tests because they test the interaction of multiple components. Integration tests were covered in the last post, Building a Microservices-based REST API with RestExpress, Java EE, and MongoDB: Part 3.

Note the short pause I have inserted before running the tests. Docker Compose does an excellent job of accounting for the required start-up order of the containers to avoid race conditions (see my previous post). However, depending on the speed of the host box, there is still a start-up period for the container’s processes to be up, running, and ready to receive traffic. Apache Log4j 2 and MongoDB startup, in particular, take extra time. I’ve seen the containers take as long as 1-2 minutes on a slow box to fully start. Without the pause, the tests fail with various errors, since the container’s processes are not all running.

Docker Compose Config 3

sleep 15
sh -v

The bash-based tests below just scratch the surface as a complete set of integration tests. However, they demonstrate an effective multi-stage testing pattern for handling the complex nature of RESTful service request requirements. The tests build upon each other. After setting up some variables, the tests register a new API client. Then, they use the new client’s API key to obtain a JWT. The tests then use the JWT to authenticate themselves, and create a new vehicle. Finally, they use the new vehicle’s id and the JWT to verify the existence for the new vehicle.

Although some may consider using bash to test somewhat primitive, the script demonstrates the effectiveness of bash’s curl, grep, sed, awk, along with regular expressions, to test our RESTful services.


# title:       Virtual-Vehicles Project Integration Tests
# author:      Gary A. Stafford (
# url:  
# description: Performs integration tests on the Virtual-Vehicles
#              microservices
# to run:      sh -v

echo --- Integration Tests ---

application="Test API Client $(date +%s)" # randomized
secret="$(date +%s | sha256sum | base64 | head -c 15)" # randomized

echo hostname: ${hostname}
echo application: ${application}
echo secret: ${secret}

### TESTS ###
echo "TEST: GET request should return 'true' in the response body"
echo ${url}
curl -X GET -H 'Accept: application/json; charset=UTF-8' \
--url "${url}" \
| grep true > /dev/null
[ "$?" -ne 0 ] && echo "RESULT: fail" && exit 1
echo "RESULT: pass"

echo "TEST: POST request should return a new client in the response body with an 'id'"
echo ${url}
curl -X POST -H "Cache-Control: no-cache" -d "{
    \"application\": \"${application}\",
    \"secret\": \"${secret}\"
}" --url "${url}" \
| grep '"id":"[a-zA-Z0-9]\{24\}"' > /dev/null
[ "$?" -ne 0 ] && echo "RESULT: fail" && exit 1
echo "RESULT: pass"

echo "SETUP: Get the new client's apiKey for next test"
echo ${url}
apiKey=$(curl -X POST -H "Cache-Control: no-cache" -d "{
    \"application\": \"${application}\",
    \"secret\": \"${secret}\"
}" --url "${url}" \
| grep -o '"apiKey":"[a-zA-Z0-9]\{24\}"' \
| grep -o '[a-zA-Z0-9]\{24\}' \
| sed -e 's/^"//'  -e 's/"$//')
echo apiKey: ${apiKey}

echo "TEST: GET request should return a new jwt in the response body"
echo ${url}
curl -X GET -H "Cache-Control: no-cache" \
--url "${url}" \
| grep '[a-zA-Z0-9_-]\{1,\}\.[a-zA-Z0-9_-]\{1,\}\.[a-zA-Z0-9_-]\{1,\}' > /dev/null
[ "$?" -ne 0 ] && echo "RESULT: fail" && exit 1
echo "RESULT: pass"

echo "SETUP: Get a new jwt using the new client for the next test"
echo ${url}
jwt=$(curl -X GET -H "Cache-Control: no-cache" \
--url "${url}" \
| grep '[a-zA-Z0-9_-]\{1,\}\.[a-zA-Z0-9_-]\{1,\}\.[a-zA-Z0-9_-]\{1,\}' \
| sed -e 's/^"//'  -e 's/"$//')
echo jwt: ${jwt}

echo "TEST: POST request should return a new vehicle in the response body with an 'id'"
echo ${url}
curl -X POST -H "Cache-Control: no-cache" \
-H "Authorization: Bearer ${jwt}" \
-d '{
    "year": 2015,
    "make": "Test",
    "model": "Foo",
    "color": "White",
    "type": "Sedan",
    "mileage": 250
}' --url "${url}" \
| grep '"id":"[a-zA-Z0-9]\{24\}"' > /dev/null
[ "$?" -ne 0 ] && echo "RESULT: fail" && exit 1
echo "RESULT: pass"

echo "SETUP: Get id from new vehicle for the next test"
echo ${url}
id=$(curl -X GET -H "Cache-Control: no-cache" \
-H "Authorization: Bearer ${jwt}" \
--url "${url}" \
| grep '"id":"[a-zA-Z0-9]\{24\}"' \
| grep -o '[a-zA-Z0-9]\{24\}' \
| tail -1 \
| sed -e 's/^"//'  -e 's/"$//')
echo vehicle id: ${id}

echo "TEST: GET request should return a vehicle in the response body with the requested 'id'"
echo ${url}
curl -X GET -H "Cache-Control: no-cache" \
-H "Authorization: Bearer ${jwt}" \
--url "${url}" \
| grep '"id":"[a-zA-Z0-9]\{24\}"' > /dev/null
[ "$?" -ne 0 ] && echo "RESULT: fail" && exit 1
echo "RESULT: pass"

Since our tests are just a bash script, they can also be ran separately from the command line, as in the screen grab below. The output, except for the colored text, is identical to what appears in the Jenkins console output.

Running Integration Tests

Tear Down

Once the integration tests have completed, we ‘tear down’ the project by removing the Virtual-Vehicle images and containers. We simply repeat the first commands we ran at the start of the Jenkins build phase. You could choose to remove the tear down step, and use this job as a way to simply build and start your multi-container application.

# remove all images and containers from this build
docker ps -a --no-trunc  | grep 'jenkins' \
| awk '{print $1}' | xargs -r --no-run-if-empty docker stop && \
docker ps -a --no-trunc  | grep 'jenkins' \
| awk '{print $1}' | xargs -r --no-run-if-empty docker rm && \
docker images --no-trunc | grep 'jenkins' \
| awk '{print $3}' | xargs -r --no-run-if-empty docker rmi

The Complete Process

The below diagram show the entire process, start to finish.

Full Process

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Building a Microservices-based REST API with RestExpress, Java EE, and MongoDB: Part 3

Develop a well-architected and well-documented REST API, built on a tightly integrated collection of Java EE-based microservices.

Virtual-Vehicles Architecture

Note: All code available on GitHub. For the version of the code that matches the details in this blog post, check out the master branch, v1.0.0 tag (after running git clone …, run a git checkout tags/v1.0.0 command).

Previous Posts

In Part One of this series, we introduced the microservices-based Virtual-Vehicles REST API example. The vehicle-themed Virtual-Vehicles microservices offers a comprehensive set of functionality, through a REST API, to application developers. In Part Two, we installed a copy of the Virtual-Vehicles project from GitHub. In Part Two, we also gained a basic understanding of how RestExpress works. Finally, we discovered how to get the Virtual-Vehicles microservices up and running.

Part Three

In part three of this series, we will take the Virtual-Vehicles for a test drive (get it? maybe it was funnier the first time…). There are several tools we can use to test the Virtual-Vehicles API. One of my favorite tools is Postman.  We will explore how to use Postman, along with the Virtual-Vehicles API documentation, to test the Virtual-Vehicles microservice’s endpoints, which compose the Virtual-Vehicles API.

Testing the API

There are three categories of tools available to test RESTful APIs, which are GUI-based applications, command line tools, and testing frameworks. Postman, Advanced REST ClientREST Console, and SmartBear’s SoapUI and SoapUI NG Pro, are examples of GUI-based applications, designed specifically to test RESTful APIs. cURL and GNU Wget are two examples of command line tools, which among other capabilities, can test APIs. Lastly, JUnit is an example of a testing framework that can be used to test a RESTful API. Surprisingly, JUnit is not only designed to manage unit tests. Each category of testing tools has their pros and cons, depending on your testing needs. We will explore all of these categories in this post as we test the Virtual-Vehicles REST API.


JUnit is probably the best known of all Java unit testing frameworks. JUnit’s website describes JUnit as ‘a simple, open source framework to write and run repeatable tests. It is an instance of the xUnit architecture for unit testing frameworks.’ Most Java developers turn to JUnit for unit testing. However, JUnit is capable of other forms of testing, including integration testing. In his post, ‘Unit Testing with JUnit – Tutorial’, Lars Vogel states ‘an integration test has the target to test the behavior of a component or the integration between a set of components. The term functional test is sometimes used as a synonym for integration test. This kind of tests allow you to translate your user stories into a test suite, i.e., the test would resemble an expected user interaction with the application.’

Testing the Virtual-Vehicles RESTful API’s operations with JUnit would be considered integration (functional) testing. At a minimum, to complete requests, we call one microservice, which in turn authenticates the JWT by calling another microservice. If authenticated, the first microservice makes a request to its MongoDB database. As Vogel stated, whereas a unit test targets a small unit of code, such as a method, the request/response operation is integration between a set of components. testing an API call requires several dependencies.

The simplest example of testing the Virtual-Vehicles API with JUnit, would be to test an HTTP GET request to return a single instance of a vehicle. The code below demonstrates how this might be done. Notice the request depends on helper methods (not included, for brevity). To request the vehicle, assuming we already have a registered client, we need a valid JWT. We also need a valid vehicle ObjectId. To obtain these two pieces of data, we call helper methods, which in turn makes the necessary request to retrieve a JWT and vehicle ObjectId.

Below are the results of the above test, run in NetBeans IDE, using the built-in support for JUnit.

JUnit Test Results

JUnit can also be run from the command line using the Maven goal, surefire:test:

Running JUnit from Command Line


One of the best-known command line tools for calling for all types of operations centered around calling a URL is cURL. According to their website, ‘curl is a command line tool and library for transferring data with URL syntax, supporting…HTTP, HTTPS…curl supports SSL certificates, HTTP POST, HTTP PUT, FTP uploading, HTTP form based upload, proxies, HTTP/2, cookies, user+password authentication (Basic, Plain, Digest, CRAM-MD5, NTLM, Negotiate, and Kerberos), file transfer resume, proxy tunneling and more.’ I prefer the website’s  briefer description, cURL ‘groks those URLs’.

Using cURL, we could make an HTTP PUT request to the Vehicle microservice’s /vehicles/{oid}.{format} endpoint. With cURL, we have the ability to add the JWT-based Authorization header and the raw request body, containing the modified vehicle object. Below is an example of that cURL command, which can be run from a terminal prompt.

The response body contains the expected modified vehicle object in JSON-format, along with a 201 Created response status.

cURL  HTTP PUT Vehicle

The cURL commands may be incorporated into many types of automated testing processes. These might be as simple as a bash script. The script could a series of automated tests, including the following: register an API client, use the API key to create a JWT, use the JWT to create a new vehicle, use the new vehicle’s ObjectId to modify that same vehicle, delete that vehicle, confirm the vehicle is removed using the count operation and returns a test results report to the user.

cURL Commands from Chrome
Quick tip, instead of hand-coding complex cURL commands, containing form data, URL parameters, and Headers, use Chrome. First, open the Chrome Developer Tools (f12). Next, using the Postman – REST Client for Chrome, available in the Chrome App Store, execute your HTTP request. Finally, in the ‘Network’ tab of the Developers tools, find and right-click on the request and select ‘Copy as cURL’. You have a complete cURL command equivalent of your Postman request, which you can paste directly into the command line or insert into a script. Below is an example of using the Postman – REST Client for Chrome to generate a cURL command.

Using Postman in Chrome to get cURL

The generated command is a bit verbose. Compare this command to the cURL command, earlier.


Similar to cURL, GNU Wget provides the ability to call the Virtual-Vehicles API’s endpoints. According to their website, ‘GNU Wget is a free software package for retrieving files using HTTP, HTTPS and FTP, the most widely-used Internet protocols. It is a non-interactive command line tool, so it may easily be called from scripts, cron jobs, terminals without X-Windows support, etc.’ Again, like cURL, we can run Wget commands from the command line or incorporate them into scripted testing processes. The Wget website contains excellent documentation.

Using Wget, we could make the same HTTP PUT request to the Vehicle microservice /vehicles/{oid}.{format} endpoint. Like cURL, we have the ability to add the JWT-based Authorization header and the raw request body, containing the modified vehicle object.

The response body contains the expected modified vehicle object in JSON-format, along with a 201 Created response status.

Wget HTTP PUT Vehicle

cURL Bash Testing

We can combine cURL and Wget with several of the tools bash provides, to develop fairly complex integration tests. The bash-based script below just scratches the surface as a complete set of integration tests. However, the tests demonstrate an efficient multi-stage test approach to handling the complex nature of RESTful service request requirements. The tests build upon each other.

After setting up some variables and doing a quick health check on one service, the tests register a new API client by calling the Authentication service. Next, they use the new client’s API key to obtain a JWT. The tests then use the JWT to authenticate themselves and create a new vehicle. Finally, they use the new vehicle’s id and the JWT to verify the existence for the new vehicle.

Although some may consider using bash to test somewhat primitive, the following script demonstrates the effectiveness of bash’s  curl, grep, sed, awk, along with regular expressions, to test our RESTful services. Note how we grep certain values from the response, such as the new client’s API key, and then use that value as a parameter for the following test request, such as to obtain a JWT.

Since these tests are just a bash script, they can from the command line, or easily called from a continuous integration tool, Such as Jenkins CI or Hudson.

Running Integration Tests


Postman, like several similar tools, is an application designed specifically for test API endpoints. The Postman website describes Postman as tool that allows you to ‘build, test, and document your APIs faster.’  There are two versions of Postman in the Chrome Web Store. They are Postman – REST Client, the in-browser extension, which we mentioned above, and Postman, the standalone application. There is also Postman Interceptor, which helps you send requests that use browser cookies through the Postman application.

Postman and similar applications, have add-ons and extensions to extend their features. In particular, Postman, which is free, offers the Jetpacks paid extension. Jetpacks add the ability to ‘write and run tests inside Postman, extract data from responses, chain requests together and test requests with thousands of variations’. Jetpacks allow you to move beyond basic one-off API request-based testing, to automated regression and performance testing.

Using Postman
Let’s use the same HTTP PUT example we used with cURL and Wget, and see how we would perform the same task with Postman. In the first screen grab below, you can see all elements of the HTTP request, including the RESTful API’s URL, URI including the vehicle’s ObjectId (/vehicles/{ObjectId}.{format}), HTTP method (PUT), Authorization Header with JWT (Bearer), and the raw request body. The raw request body contains a JSON representation of the vehicle we want to update. Note how Postman saves the request in history so we can easily replay it later.

Postman HTTP PUT of Vehicle

In the next screen-grab, we see the response to the HTTP PUT request. Note the response body, response status, timing, and response headers.

Postman HTTP POST of Vehicle Response

Looking at the response body in Postman, you easily see the how RestExpress demonstrates the RESTful principle we discussed in Part Two of the series, HATEOAS (Hypermedia as the Engine of Application State). Note the link to this vehicle’s ‘self’ href) and the entire vehicles collection (‘up’ href).

Postman Collections
A great feature of Postman with Jetpacks is Collections. Collections are sets of requests, which can be saved, recalled, and shared. The Collection Runner runs requests in a collection, in the order in which you set them. Ordered collections are ideal for the Virtual-Vehicles API. The screen grab below shows a collection of requests, arranged in the order we would execute them to test the Virtual-Vehicles API, as it applies to specifically to vehicle CRUD operations:

  1. Execute HTTP POST request to register the new API client, passing the application name and a shared secret in the request
    Receive the new client’s API key in response
  2. Execute HTTP GET to request, passing the new client’s API key and the shared secret in the request
    Receive the new JWT in response
  3. Execute HTTP POST request to create a new vehicle, passing the JWT in the header for authentication (used for all following requests)
    Receive the new vehicle object in response
  4. Execute HTTP PUT request to modify the new vehicle, using the vehicle’s ObjectId
    Receive the modified vehicle object in response
  5. Execute HTTP GET to request the modified vehicle, to confirm it exists in the expected state
    Receive the vehicle object in response
  6. Execute HTTP DELETE request to delete the new vehicle, using the vehicle’s ObjectId
  7. Execute HTTP GET to request the new vehicle and to confirm it has been removed
    Receive a 404 Not Found status response, as expected

Postman Ordered Series of REST Calls

Using saved collections for testing the Virtual-Vehicles API is a real-time saving. However, the collections cannot easily be re-run without hand-editing or some advanced scripting. In the simple example above, we hard-coded a JWT and vehicle ObjectId in the requests. Unfortunately, the JWT has an expiration of only 10 hours by default. More immediately, the ObjectId is unique. The earlier collection test run created, then deleted, the vehicle with that ObjectId.

Negative Testing
You may also perform negative testing with Postman. For example, do you receive the expected response when you don’t include the Authorization Header with JWT in a request (401 Unauthorized status)? When you include a JWT, which has expired (401 Unauthorized status)? When you request a vehicle, whose ObjectId is incorrect or is not found in the database (400 Bad Request status)? Do you receive the expected response when you call an actual service, but an endpoint that doesn’t exist (405 Method Not Allowed)?

Negative Testing in Postman

Postman Test Automation

In addition to manually viewing the HTTP response, to verify the results of a request, Postman allows you to write and run automated tests for each request. According to their website, a ‘Postman test is essentially JavaScript code which sets values for the special tests object. You can set a descriptive key for an element in the object and then say if it’s true or false’. This allows you to write a set of response validation tests for each request.

Below is a quick example of testing the same HTTP POST request, used to create the new API client, above. In this example, we:

  1. Test that the Content-Type response header is present
  2. Test that the HTTP POST successfully returned a 201 status code
  3. Test that the new client’s API key was returned in the response body
  4. Test that the response time was less than 200ms

Postman Test Editor Example

Reviewing Postman’s ‘Tests’ tab, above, observe the four tests have run successfully. Using the Postman’s testing feature, you can create even more advanced tests, eliminating the need to manually validate responses.

This post demonstrates a small subset of the features Postman and other similar applications provide for testing RESTful API. The tools and processes you use to test your RESTful API will depend on the stage of development and testing you are in, as well as the existing technology stacks you build, and on which you host your services.

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Building a Microservices-based REST API with RestExpress, Java EE, and MongoDB: Part 2

Develop a well-architected and well-documented REST API, built on a tightly integrated collection of Java EE-based microservices.

Virtual-Vehicles Architecture

Note: All code available on GitHub. For the version of the code that matches the details in this blog post, check out the master branch, v1.0.0 tag (after running git clone …, run a ‘git checkout tags/v1.0.0’ command).

Previous Post

In Part One of this series, we introduced the microservices-based Virtual-Vehicles REST API example. The vehicle-themed Virtual-Vehicles microservices offers a comprehensive set of functionality, through a REST API, to application developers. The developers, in turn, will use the Virtual-Vehicles REST API’s functionality to build applications and games for their end-users.

In Part One, we also decided on the proper amount and responsibility of each microservice. We also determined the functionality of each microservice to meet the hypothetical functional and nonfunctional requirements of Virtual-Vehicles. To review, the four microservices we are building, are as follows:

Virtual-Vehicles REST API Resources

Microservice Purpose (Business Capability) Functions
Manage API clients and
JWT authentication
  • Create a new API client (public)
  • Read, filter, sort, count, paginate API clients (admin)
  • Read a single API client (public)
  • Update an existing API client (public)
  • Delete an existing API client (admin)
  • Create new JWT (public)
  • Validate a JWT (internal)
  • Service health ping (admin)
Manage virtual vehicles
  • Create a new vehicle (public)
  • Read, filter, sort, count, paginate vehicles (admin)
  • Read a single vehicle (public)
  • Update an existing vehicle (public)
  • Delete an existing vehicle (admin)
  • Validate a JWT (internal)
  • Service health ping (admin)
Manage maintenance on vehicles
  • Create a new maintenance record (public)
  • Read, filter, sort, count, paginate maintenance records (admin)
  • Read a single maintenance record (public)
  • Update an existing maintenance record (public)
  • Delete an existing maintenance record (admin)
  • Validate a JWT (internal)
  • Service health ping (admin)
Valet Parking
Manage a valet service to park for vehicles
  • Create a new valet parking transaction (public)
  • Read, filter, sort, count, paginate valet parking transactions (admin)
  • Read a single valet parking transaction (public)
  • Update an existing valet parking transaction (public)
  • Delete an existing valet parking transaction (admin)
  • Validate a JWT (internal)
  • Service health ping (admin)

To review, the first five functions for each service are all basic CRUD operations: create (POST), read (GET), readAll (GET), update (PUT), delete (DELETE). The readAll function also has find, count, and pagination functionality using query parameters. Unfortunately, RestExpress does not support PATCH for updates. However, I have updated RestExpress’ PUT HTTP methods to return the modified object in the response body instead of the nothing (status of 201 Created vs. 200 OK). See StackOverflow for an explanation.

All services also have an internal authenticateJwt function, to authenticate the JWT, passed in the HTTP request header, before performing any operation. Additionally, all services have a basic health-check function, ping (GET). There are only a few other functions required for our Virtual-Vehicles example, such as for creating JWTs.

 Part Two Introduction

In Part Two, we will build our four Virtual-Vehicles microservices. Recall from our first post, we will be using RestExpress. RestExpress composes best-of-breed open-source tools to enable quickly creating RESTful microservices that embrace industry best practices. Those best-of-breed tools include Java EE, Maven, MongoDB, and Netty, among others.

In this post, we will accomplish the following:

  • Create a default microservice project in NetBeans using RestExpress MongoDB Maven Archetype
  • Understand the basic structure of a default RestExpress microservice project
  • Review the changes made to the default RestExpress microservice project to create the Virtual-Vehicles example
  • Compile and run the individual microservices directly from NetBeans

I used NetBeans IDE 8.0.2 on Linux Ubuntu 14.10 to build the microservices. You may also follow along in other IDE’s, such as Eclipse or IntelliJ, on Mac or Windows. We won’t cover installing MongoDB, Maven, and Java. I’ll assume if your building enterprise applications, you have the basics covered.

Using the RestExpress MongoDB Maven Archetype

All the code for this project is available on GitHub. However, to understand RestExpress, you should go through the exercise of scaffolding a new microservice using the RestExpress MongoDB Maven Archetype. You will also be able to use this default microservice project to compare and contrast to the modified versions, used in the Virtual-Vehicles example. The screen grabs below demonstrate how to create a new microservice project using the RestExpress MongoDB Maven Archetype. At the time of this post, the archetype version was restexpress-mongodb version 1.15.

New Maven Project from Archetype Step 1

New Maven Project from Archetype Step 2

New Maven Project from Archetype Step 2

Default Project Architecture

Reviewing the two screen grabs below (Project tab), note the key components of the RestExpress MongoDB Maven project, which we just created:

  • Base Package (com.example.vehicle)
    • Configuration class reads in environment properties (see Files tab) and instantiates controllers
    • Constants class contains project constants
    • Relationships class defines linking resource which aids service discoverability (HATEOAS)
    • Main executable class
    • Routes class defines the routes (endpoints) exposed by the service and the corresponding controller class
  • Model/Controllers Packages (com.example.vehicle.objectid and .uuid)
    • Entity class defines the data entity – a Vehicle in this case
    • Controller class contains the methods executed when the route (endpoint) is called
    • Repository class defines the connection details to MongoDB
    • Service class contains the calls to the persistence layer, validation, and business logic
  • Serialization Package (com.example.vehicle.serialization)
    • XML and JSON serialization classes
    • Object ID and UUID serialization and deserialization classes

New Maven Project from Archetype Project View

New Maven Project from Archetype Projects View

Again, I strongly recommend reviewing each of these package’s classes. To understand the core functionality of RestExpress, you must understand the relationships between RestExpress microservice’s Route, Controller, Service, Repository, Relationships, and Entity classes. In addition to reviewing the default Maven project, there are limited materials available on the Internet. I would recommend the RestExpress Website on GitHub, RestExpress Google Group Forum, and the YouTube 3-part video series, Instant REST Services with RESTExpress.

Unit Tests?
Disappointingly, the current RestExpress MongoDB Maven Archetype sample project does not come with sample JUnit unit tests. I am tempted to start writing my own unit tests if I decided to continue to use the RestExpress microservices framework for future projects.

Properties Files

Also included in the default RestExpress MongoDB Maven project is a Java properties file ( This properties file is displayed in the Files tab, as shown below. The default properties file is located in the ‘dev’ environment config folder. Later, we will create an additional properties file for our production environment.

Default Properties File

Within the ‘dev’ environment, each microservice is configured to start on separate ports  (i.e. port = 8581). Feel free to change the service’s port mappings if they conflict with previously configured components running on your system. Be careful when changing the Authentication service’s port, 8587, since this port is also mapped in all other microservices using the authentication.port property (authentication.port = 8587). Make sure you change both properties, if you change Authentication service’s port mapping.

Base URL
Also, in the properties files is the base.url property. This property defines the URL the microservice’s endpoints will be expecting calls from, and making internal calls between services. In our post’s example, this property in the ‘dev’ environment is set to localhost (base.url = http://localhost). You could map an alternate hostname from your hosts file (/etc/hosts). We will do this in a later post, in our ‘prod’ environment, mapping the base.url property to Virtual-Vehicles (base.url = In the ‘dev’ environment properties file, MongoDB is also mapped to localhost (i.e. mongodb.uri = mongodb://

Metrics Plugin and Graphite
RestExpress also uses the properties file to hold configuration properties for Metrics Plugin and Graphite. The Metrics Plugin and Graphite are both first class citizens of RestExpress. Below is the copy of the Vehicles service file for the ‘dev’ environment. Note, the Metrics Plugin and Graphite are both disabled in the ‘dev’ environment.

Choosing a Data Identification Method

RestExpress offers two identification models for managing data, the MongoDB ObjectId and a Universally Unique Identifier (UUID). MongoDB uses an ObjectId to identify uniquely a document within a collection. The ObjectId is a special 12-byte BSON type that guarantees uniqueness of the document within the collection. Alternately, you can use the UUID identification model. The UUID identification model in RestExpress uses a UUID, instead of a MongoDB ObjectId. The UUID also contains createdAt and updatedAt properties that are automatically maintained by the persistence layer. You may stick with ObjectId, as we will in the Virtual-Vehicles example, or choose the UUID. If you use multiple database engines for your projects, using UUID will give you a universal identification method.

Project Modifications

Many small code changes differentiate our Virtual-Vehicles microservices from the default RestExpress Maven Archetype project. Most changes are superficial; nothing changed about how RestExpress functions. Changes between the screen grabs above, showing the default project, and the screen grabs below, showing the final Virtual-Vehicles microservices, include:

  • Remove all packages, classes, and code references to the UUID identification methods (example uses ObjectId)
  • Rename several classes for convenience (dropped use of word ‘Entity’)
  • Add the Utilities (com.example.utilities) and Authentication (com.example.authenticate) packages

Final Virtual-Vehicles Microservices Projects

Final Virtual-Vehicles Microservices Projects


Following a key principle of microservices mentioned in the first post, Decentralized Data Management, each microservice will have its own instance of a MongoDB database associated with it. The below diagram shows each service and its corresponding database, collection, and fields.

Virtual-Vehicles Database Diagram
From the MongoDB shell, we can observe the individual instances of the four microservice’s databases.

MongoDB Virtual-Vehicles Databases

In the case of the Vehicle microservice, the associated MongoDB database is virtual_vehicle. This database contains a single collection, vehicles. While the properties file defines the database name, the Vehicles entity class defines the collection name, using the org.mongodb.morphia.annotations classes annotation functionality.

Looking at the virtual_vehicle database in the MongoDB shell, we see that the sample document’s fields correspond to the Vehicle entity classes properties.

MongoDB vehicles Document
Each of the microservice’s MongoDB databases are configured in the file, using the mongodb.uri property. In the ‘dev’ environment we use localhost as our host URL (i.e. mongodb.uri = mongodb://localhost:27017/virtual_vehicle).

Authentication and JSON Web Tokens

The three microservices, Vehicle, Valet, and Maintenance, are almost identical. However, the Authentication microservice is unique. This service is called by each of the other three services, as well as also being called directly. The Authentication service provides a very basic level of authentication using JSON Web Tokens (JWT), pronounced ‘jot‘.

Why do we want authentication? We want to confirm that the requester using the Virtual-Vehicles REST API is the actual registered API client they are who they claim to be. JWT allows us to achieve this requirement with minimal effort.

According to, ‘a JSON Web Token is a compact URL-safe means of representing claims to be transferred between two parties. The claims in a JWT are encoded as a JSON object that is digitally signed using JSON Web Signature (JWS).‘ I recommend reviewing the JWT draft standard to fully understand the structure, creation, and use of JWTs.

Virtual-Vehicles Authentication Process
There are different approaches to implementing JWT. In our Virtual-Vehicles REST API example, we use the following process for JWT authentication:

  1. Register the new API client by supplying the application name and a shared secret (one time only)
  2. Receive an API key in response (one time only)
  3. Obtain a JWT using the API key and the shared secret (each user session or renew when the previous JWT expires)
  4. Include the JWT in each API call

In our example, we are passing four JSON fields in our set of claims. Those fields are the issuer (‘iss’), API key, expiration (‘exp’), and the time the JWT was issued (‘ait’). Both the ‘iss’ and the ‘exp’ claims are defined in the Authentication service’s file (jwt.expire.length and jwt.issuer).

Expiration and Issued date/time use the JWT standard recommended “Seconds Since the Epoch“.  The default expiration for a Virtual-Vehicles JWT is set to an arbitrary 10 hours from the time the JWT was issued (jwt.expire.length = 36000). That amount, 36,000, is equivalent to 10 hours x 60 minutes/hour x 60 seconds/minute.

Decoding a JWT
Using the site’s JT Debugger tool, I have decoded a sample JWT issued by the Virtual-Vehicles REST API, generated by the Authentication service. Observe the three parts of the JWT, the JOSE Header, Claims Set, and the JSON Web Signature (JWS).

Decoded JWT

The JWT’s header indicates that our JWT is a JWS that is MACed using the HMAC SHA-256 algorithm. The shared secret, passed by the API client, represents the HMAC secret cryptographic key. The secret is used in combination with the cryptographic hash function to calculate the message authentication code (MAC). In the example below, note how the API client’s shared secret is used to validate our JWT’s JWS.

Sequence Diagrams of Authentication Process
Below are three sequence diagrams, which detail the following processes: API client registration process, obtaining a new JWT, and a REST call being authenticated using the JWT. The end-user of the API self-registers their application using the Authentication service and receives back an API key. The API key is unique to that client.

Register API Client (Authentication Service)

The end-user application then uses the API key and the shared secret to receive a JWT from the Authentication service.

Requesting a JWT (Authentication Service)After receiving the JWT, the end-user application passes the JWT in the header of each API request. The JWT is validated by calling the Authentication service. If the JWT is valid, the request is fulfilled. If not valid, a ‘401 Unauthorized’ status is returned.

API Call with JWT Passed in Header (Vehicle Service)JWT Validation
The JWT draft standard recommends how to validate a JWT. Our Virtual-Vehicles Authentication microservice uses many of those criteria to validate the JWT, which include:

  1. API Key – Retrieve API client’s shared secret from MongoDB, using API key contained in JWT’s claims set (secret is returned; therefore API key is valid)
  2. Algorithm – confirm the algorithm (‘alg’), found in the JWT Header, which used to encode JWT, was ‘HS256’ (HMAC SHA-256)
  3. Valid JWS – Use the client’s shared secret from #1 above, decode HMAC SHA-256 encrypted JWS
  4. Expiration – confirm JWT is not expired (‘exp’)

Inter-Service Communications

By default, the RestExpress Archetype project does not offer an example of communications between microservices. Service-to-service communications for microservices is most often done using the same HTTP-based REST calls used to by our Virtual-Vehicles REST API. Alternately, a message broker, such as RabbitMQ, Kafka, ActiveMQ, or Kestrel, is often used. Both methods of communicating between microservices, referred to as ‘inter-service communication mechanisms’ by InfoQ, have their pros and cons. The InfoQ website has an excellent microservices post, which discusses the topic of service-to-service communication.

For the Virtual-Vehicles microservices example, we will use HTTP-based REST calls for inter-service communications. The primary service-to-service communications in our example, is between the three microservices, Vehicle, Valet, and Maintenance, and the Authentication microservice. The three services validate the JWT passed in each request to a CRUD operation, by calling the Authentication service and passing the JWT, as shown in the sequence diagram, above. Validation is done using an HTTP GET request to the Authentication service’s .../jwts/{jwt} endpoint. The Authentication service’s method, called by this endpoint, minus some logging and error handling, looks like the following:

Primarily, we are using the and packages, along with the org.restexpress.Request class to build and send our HTTP request to the Authentication service. Alternately, you could use just the org.restexpress package to construct request and handle the response. This same basic method structure shown above can be used to create unit tests for your service’s endpoints.

Health Ping

Each of the Virtual-Vehicles microservices contain a DiagnosticController in the .utilities package. In our example, we have created a ping() method. This simple method, called through the .../utils/ping endpoint, should return a 200 OK status and a boolean value of ‘true’, indicating the microservice is running and reachable. This route’s associated method could not be simpler:

The ping health check can even be accessed with a simple curl command, curl localhost:8581/vehicles/utils/ping.

In a real-world application, we would add additional health checks to all services, providing additional insight into the health and performance of each microservice, as well as the service’s dependencies.

API Documentation

A well written RESTful API will not require extensive documentation to understand the API’s operations. Endpoints will be discoverable through linking (see Response Body links section in below example). API documentation should provide HTTP method, required headers and URL parameters, expected response body and response status, and so forth.

An API should be documented before any code is written, similar to TDD. The API documentation is the result of a clear understanding of requirements. The API documentation should make the coding even easier since the documentation serves as a further refinement of the requirements. The requirements are an architectural plan for the microservice’s code structure.

Sample Documentation
Below, is a sample of the Virtual-Vehicles REST API documentation. It details the function responsible for creating a new API client. The documentation provides a brief description of the function, the operation’s endpoint (URI), HTTP method, request parameters, expected response body, expected response status, and even a view of the MongoDB collection’s document for a new API client.

Virtual-Vehicles API Guide

You can download a PDF version of the Virtual-Vehicles RESTful API documentation on GitHub or review the source document on Google Docs. It contains general notes about the API, and details about every one of the API’s operations.

Running the Individual Microservices

For development and testing purposes, the easiest way to start the microservices is in NetBeans using the Run command. The Run command executes the Maven exec goal. Based on the DEFAULT_ENVIRONMENT constant in the org.restexpress.util Environment class, RestExpress will use the ‘dev’ environment’s file, in the project’s /config/dev directory.

Alternately, you can use the RestExpress project’s recommended command from a terminal prompt to start each microservice from its root directory (mvn exec:java -Dexec.mainClass=test.Main -Dexec.args="dev"). You can also use this command to switch from the ‘dev’ to ‘prod’ environment properties (-Dexec.args="prod").

You may use a variety of commands to confirm all the microservices are running. I prefer something basic like sudo netstat -tulpn | grep 858[0-9]. This will find all the ports within the ‘dev’ port range. For more in-depth info, you can use a command like ps -aux | grep com.example | grep -v grep

Microservices Running

Part Three: Testing our Services

We now have a copy of the Virtual-Vehicles project pulled from GitHub, a basic understanding of how RestExpress works, and our four microservices running on different ports. In Part Three of this series, we will take them for a drive (get it?). There are many ways to test our service’s endpoints. One of my favorite tools is Postman. we will explore how to use several tools, including Postman, and our API documentation, to test our microservice’s endpoints.

Postman Preview

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