Problem migrating use of docker-compose config

[NeilJed]

Due to issues with current versions of Python and docker-compose needing PyYaml 5.4.1, I want to try and migrate to using python-on-whales to get away from the legacy docker-compose. One stanza of code that's causing me problems is the following which is being used to validate if the compose value is valid:

    command = [
        '/usr/local/bin/docker', 'compose',
        '--file',
        compose_file_path,
        'config',
        '--quiet'
    ]
    # provide environment variables used by the compose file to avoid warnings
    environment = {
        'DEFAULT_IAM_ROLE': '',
        'ENV': '',
        'Name': '',
        'VPC': '',
    }
    return subprocess.call(command, env=environment)

If the return code is non-zero then the config is considered invalid.

I attempted to replicate it with the following:

    docker = python_on_whales.DockerClient(compose_files=[compose_file_path])
    docker.compose.config()

It's returning a JSON representation of the file which I assume I should take as it being good? I purposely gave it a bad file which resulted in an exception.

I guess my question is:

• Is my assumption that it returning JSON means the file is good?
• Should I assume any exception is an indication it's bad?
• Should I care about the original environment variables in the original stanza?