docker-service-api

Guava Service implementations for unified service mangagement of docker containers, spring boot applications and dockerized spring boot applications.

Concepts

Service Abstraction

The service abstraction comprises classes to abstract Spring Boot components and docker services alike. It is based on Guava Services.

Docker Service Abstraction

ServiceBuilder

A ServiceBuilder is simply a Supplier of something that is a service. Implementations of this interface should provide getters and setters for configurations. Finally, a call to .get() should then return a service based on the current state of builder. Future changes to the builder should not affect already created services.

public interface ServiceBuilder<T extends Service>
    extends Supplier<T>
{
}

Docker Service Abstractions

A DockerService extends a guava Service with the following method declarations:

public interface DockerService
    extends Service
{
    String getImageName();
    String getContainerId();
    Integer getExitCode();
}

In order to create docker services, at mininum an image name and its environment is needed.

The DockerServiceFactory handles exactly this basic case.

public interface DockerServiceFactory<T extends DockerService> {
    T create(String imageName, Map<String, String> env);
}

myDockerServiceFactory.create("my-image", ImmutableMap.<String, String>builder()
                                  .put("SOME_OPTION", "A")
                                  .put("SOME_OTHER_OPTION", "B")
                                  .build());

However, concrete implementations of DockerServiceFactory may introduce state - such a base environment. If such a factory was then shared between components that modified this state, then calls to .create() would interfere with each other.

In order to isololate docker service creation, additional interfaces are provided.

The DockerServiceBuilder interface extends ServiceBuilder with common docker-related configuration attributes. Further sub-classes may introduce more configuration options. Each call to .get() is then expected to yield a fresh service in regard to the current state of the builder.

public interface DockerServiceBuilder<T extends DockerService>
    extends ServiceBuilder<T>
{
    String getImageName();
    DockerServiceBuilder<T> setImageName(String imageName);
    Map<String, String> getLocalEnvironment();
    DockerServiceBuilder<T> setLocalEnvironment(Map<String, String> environment);
}

Finally, a DockerServiceBuilderFactory is a supplier of idependent and (usually) preconfigured DockerServiceBuilder instances.

public interface DockerServiceBuilderFactory<B extends DockerServiceBuilder<? extends DockerService>>
    extends Supplier<B>
{
}

Docker Service Implementations