spring-boot-on-kubernetes-with-jib-example

Spring Boot on Kubernetes

The purpose of this example is to demonstrate the following:

• How you can use the kubernetes-spring-starter.
• How dekorate detects that this is a web app and automatically configures services and probe.
• How you can perform end-to-end testing of the application.
• How you can trigger a docker build after the compilation.

The application is using:

<dependency>
  <groupId>io.dekorate</groupId>
  <artifactId>kubernetes-spring-starter</artifactId>
  <version>${project.version}</version>
</dependency>

Which contains all the required modules, including the annotation processors that detects spring web applications.

The Main.class is annotated with @KubernetesApplication which triggers the resource generation. It's also annotated with @DockerBuild. This annotation allows the user to trigger a docker build after the compilation, by passing the system property dekorate.build=true to the build for example:

mvn clean install -Ddekorate.build=true

Note: Dekorate is not going to generate a Dockerfile for you. It expects to find one in the root of the module and it also expects to find the docker binary pointing to a running docker daemon.

The spring web application processor will detect our Controller.java, and will:

• add container port 8080
• expose port 8080 as a service
• add readiness and liveness probes.

Integration testing

For the purpose of integration testing it includes:

<dependency>
  <groupId>io.dekorate</groupId>
  <artifactId>kubernetes-junit-starter</artifactId>
  <version>${project.version}</version>
  <scope>test</scope>
</dependency>

This annotation will bring in the junit5 extension that Dekorate provides, which allows you to run integration tests via the @KubernetesIntegrationTest annotation. The integration test is SpringBootOnKubernetesIT.java and it demonstrates:

• how you can deploy the application for end to end testing
• how use can use the kubernetes client from within the test to connect to the application.

The tests are going to be automatically run when building the application. For example:

mvn clean install

Note: To run the integration tests an actual kubernetes environment is required. As the integration test requires a docker build to run, the tests will only run if an existing Dockerfile is found, and if the docker daemon used is the one use by kubernetes.