Docker compose db_migration is missing gcp volume

[MathijsNL]

After running a fresh instance the container for the migration throws this error.

 docker logs diffgram-db_migration-1
INFO  [alembic.runtime.migration] Context impl PostgresqlImpl.
INFO  [alembic.runtime.migration] Will assume transactional DDL.
[2024-04-02 20:15:20,695] ERROR data_tools_core_gcp.py Line 42: Error intializing GCP Client
ERROR [shared] Error intializing GCP Client
Traceback (most recent call last):
  File "/app/shared/data_tools_core_gcp.py", line 30, in __init__
    self.gcs = storage.Client(settings.GOOGLE_PROJECT_NAME)
               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/local/lib/python3.11/site-packages/google/cloud/storage/client.py", line 121, in __init__
    super(Client, self).__init__(
  File "/usr/local/lib/python3.11/site-packages/google/cloud/client.py", line 319, in __init__
    Client.__init__(
  File "/usr/local/lib/python3.11/site-packages/google/cloud/client.py", line 178, in __init__
    credentials, _ = google.auth.default(scopes=scopes)
                     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/local/lib/python3.11/site-packages/google/auth/_default.py", line 459, in default
    credentials, project_id = checker()
                              ^^^^^^^^^
  File "/usr/local/lib/python3.11/site-packages/google/auth/_default.py", line 221, in _get_explicit_environ_credentials
    credentials, project_id = load_credentials_from_file(
                              ^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/local/lib/python3.11/site-packages/google/auth/_default.py", line 107, in load_credentials_from_file
    raise exceptions.DefaultCredentialsError(
google.auth.exceptions.DefaultCredentialsError: File /gcp/gcp-service-account.json was not found.

It seems it is missing the volume:

  db_migration:
    image: diffgram/default:${DIFFGRAM_VERSION_TAG}
    env_file:
      - .env
    environment:
      PYTHONPATH: "/app/"
    command: ["/app/db-init.sh", "${DATABASE_HOST}"]
    depends_on:
      db:
        condition: service_healthy
      rabbitmq:
        condition: service_healthy
# The volume is currently missing
    volumes:
    - ${GCP_SERVICE_ACCOUNT_FILE_PATH}:/gcp/gcp-service-account.json

https://github.com/diffgram/diffgram/blob/master/docker-compose.yaml#L92-L103

[oss-maintainer-12]

@MathijsNL Thanks for flagging this.
By chance have you had time to also test if adding that volume fixes it?
This file hasn't change in a while so I'm not sure what would have caused the regression, but if adding the volume works we can simply add it to the file.
I should not that GCP is optional in theory - not sure if that matters for this context

[MathijsNL]

The container doesn't throw any errors anymore when I add the volume. But I am also not completely sure why the db migration would need the GCP.