Option to ignore ports in docker-compose files

[wulfsberg]

When using DockerComposeContainer to launch an existing docker-compose file, Testcontainers expose random ports for the services, which can be picked up with the .getServicePort(..., ...) method.

However, if the docker-compose file includes ports definitions, Testcontainers will also expose those fixed ports, defeating the purpose of avoiding collisions by randomizing ports.
I am aware that the documentations states that "it is not necessary to define ports to be exposed in the YAML file; this would inhibit reuse/inclusion of the file in other contexts". But at the same time, DockerComposeContainer is meant to be used in situations where docker-compose files are already in use, and for me, it is convenient that those existing docker-compose files do include the port definitions.

So it would be convenient if Testcontainers could simply ignore the ports in the docker-compose files, and only expose the randomly assigned numbers. As far as I can see, this is not currently an option(?)

[kiview]

While we already parse Docker Compose files, we only do this for pulling the images and ultimately delegate everything else to Docker Compose, with a verbatim version of the Docker Compose file.

While I can absolutely understand this feature request from a UX perspective, I feel this is out-of-scope of DockerComposeContainer, at least for the time being.

[ivanmartinvalle]

I'm running into the same issue. Some workarounds:

• commit a copy of docker-compose.yml to source control, remove the port definitions, and then reference the copy. this is fairly quick.
• read the canonical docker-compose.yml file into memory, update the file, write it to a temporary file, and reference the temporary file

[Allsimon]

This is the dirty workaround I'm using, posting it here in case someone else find it useful:

    public static final DockerComposeContainer<?> environment = new DockerComposeContainer(patchDockerCompose("../docker-compose.yml"));
    
    @SneakyThrows
    public static File patchDockerCompose(String pathName) {
        var mapper = new ObjectMapper(new YAMLFactory());
        var realDockerCompose = new File(pathName);
        var yaml = mapper.readTree(realDockerCompose);

        var services = ((ObjectNode) yaml.get("services"));
        services.elements().forEachRemaining(service -> ((ObjectNode) service).remove("ports")); // don't expose ports to the host

        var patchedFileContent = mapper.writeValueAsString(yaml);

        var modifiedDockerCompose = createTempFile("docker-compose-test-", ".yml", realDockerCompose.getParentFile());
        modifiedDockerCompose.deleteOnExit();
        return Files.writeString(modifiedDockerCompose.toPath(), patchedFileContent).toFile();
    }