Spring Boot service calling another one, how to with spring-boot-docker-compose

Question

I went through tutorials https://www.baeldung.com/docker-compose-support-spring-boot and https://www.youtube.com/watch?v=lS1GwdIfk0c . These explain how to make a Spring Boot application to use a dockerized product, e.g. some database.

But how about to make the Spring Boot service to call another my Spring Boot service, can spring-boot-docker-compose help?

I know to write docker-compose in terms of making two Spring Boot services communicate but what I don't know is how spring-boot-docker-compose can help.

Answer 1

Make the "another Spring Boot service" just another dockerized application and add it to your docker compose.

So you need to:

1. Create a Dockerfile for your service, something like this:

FROM bellsoft/liberica-openjdk-alpine:17
COPY target/yourapp-0.0.1-SNAPSHOT.jar /app/yourapp.jar
ENTRYPOINT ["java", "-jar", "/app/yourapp.jar"]

2. Build and publish the image to the local Docker repo. Go to the directory where the Dockerfile is and run docker build . -t tst/yourapp:0.0.1

3. add it to your docker compose of the main service - set image, container-name, environment, ports, ... do not forget networks and giving your service access to the network of the to-be-called service and also depends_on to start it after it the all the to-be-called services...

If the service communicates synchronously without some pooling/autor-reconnection or similar mechanism, you'll have to add connection retries via org.springframework.retry.support.RetryTemplate

As for spring-boot-docker-compose, you just add it to your project as dependency, for maven it looks this way:

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-docker-compose</artifactId>
</dependency>

Then you need to point to it from your application config, YAML version:

spring:
  docker:
    compose:
      file: docker/compose-local.yaml
      enabled: true
      skip:
        in-tests: true

When you start the app by mvn spring-boot:run or from IDE, spring-boot-docker-compose should start the container before it starts your app.