Should compose2nix reconsider relative volumes mounts from cwd?

[bLuka]

Hi!

compose2nix really is awesome, and exceeds all of my expectations!

As I’m migrating a bunch of Docker Compose definitions, I was wondering if it would be wise to add an option to the parser to handle relative volume mountpoints more effectively.

It would leverage the issue where a docker-compose.yml contains a bunch of relative mountpoints from the current working directory.

Current behavior

Currently, with the following definition:

services:
   foo:
      image: bar
      volumes:
        - ./baz:/baz

Using compose2nix -project fo, the following Nix definition is generated:

{
  # …
  # Containers
  virtualisation.oci-containers.containers."foo-foo" = {
    image = "bar";
    volumes = [
      "baz:/baz:rw" # <---
    ];
    # …
  };
  # …
}

Expected

Instead, I’d expect either a warning or the following output:

    volumes = [
      "/some/cwd/from/compose2nix/baz:/baz:rw"
    ];

Propositions

I considered those 2 options:

1. Re-use the current working directory during compose2nix call (fastest but dumbest, and might break things if docker-compose wasn’t meant to be called from the same place compose2nix have been)
2. Add a flag to prefix the relative volume paths by the given directory (smartest, but requires checking help and yet another mandatory flag)

In any way, by default, I believe we should not let compose2nix trim the ./ prefix from relative volume mountpoints. We might want to consider issuing a warning instead (as it is done using -check_systemd_mounts)