Description

Hello. I have noticed that the way I find the docker-compose.yml file in a multi-module project is different in normal and test situations.

Reproduce

Spring Boot version

3.3.4

Build script

dependencies {
    implementation("org.springframework.boot:spring-boot-starter")
    implementation("org.jetbrains.kotlin:kotlin-reflect")
    testAndDevelopmentOnly("org.springframework.boot:spring-boot-docker-compose") // for docker compose
    testImplementation("org.springframework.boot:spring-boot-starter-test")
    testImplementation("org.jetbrains.kotlin:kotlin-test-junit5")
    testRuntimeOnly("org.junit.platform:junit-platform-launcher")
}

application.yml

spring:
  docker:
    compose:
      file: docker/docker-compose.yml
      lifecycle-management: start_and_stop
      skip:
        in-tests: false

Gradle project structure

├── README.md
├── docker
│   └── docker-compose.yml -> docker compose file
├── spring-mvc
│   ├── build.gradle.kts
│   └── src -> SpringBootApplication class

Result

I put a breakpoint in the DockerComposeFile.of(File file) method and debugged it
file.getAbsolutePath()
non test case: PROJECT_ABSOLUTE_PATH/docker/docker-compose.yml -> works fine
test case: PROJECT_ABSOLUTE_PATH/spring-mvc/docker/docker-compose.yml -> IllegalArgumentException with Docker Compose file 'docker/docker-compose.yml' does not exist

Conclusion

When reading the docker compose file location set in application.yml in a multi-module project, the path seems to be different when testing and when not testing.

Comment From: wilkinsona

The path is resolved against the current working directory. If the working directory is different in the test and non-test cases then the resolved absolute path will also be different. Without knowing how you're running the two different cases, I can't really comment further but, as things stand, I would guess that this is a duplicate of https://github.com/spring-projects/spring-boot/issues/40512 and you need to adjust your IDE's configuration.

Comment From: doljae

Hello @wilkinsona Thanks to your explanation, I realized that the way I was using before was working because of the default settings in the IDE, even though it is not supported by Spring.

I modified my docker-compose.yml file and related directories to be located inside the module rather than in the root directory and found that it worked fine.

I have one question: what is the difference between the working directory and the application directory? I've been googling but haven't seen a clear answer 🥲