Failure to expand environment variables properly cross-platform.

[Thvyze]

v1.3.0 broke my dev setup on Windows. Bash-style environment variables under environment section in docker-compose.yml are passed through unresolved to podman (run) command-line.

NOT a bug in Podman.

Steps to reproduce the behavior:

1. Use an image such as: php:8.4-apache
2. In the environment section of the docker-compose.yml, define variable(s) such as:

APACHE_LOG_DIR: "${APACHE_LOG_DIR:-/var/www/app/storage/logs/apache2}"
PHP_MEMORY_LIMIT: "${PHP_MEMORY_LIMIT:-128M}"

3. Try a command such as: podman-compose.exe up --build

Expected behavior
Environment variable values such as above should be passed through as already resolved (evaluated).

Actual behavior
Environment variable values are passed through raw (unresolved).

Output

$ podman-compose version
podman-compose version 1.3.0
podman version 5.3.2

Environment:

• OS: Windows 11 Pro 24H2 26100.2894
• podman version: 5.3.2 remote
• podman compose version: pip: podman_compose-1.3.0.dist

Additional context

This issue was did not manifest while using previous version from pip, probably because environment variables were not passed through at all ??

Solution/Workaround:

# LocalCache\local-packages\Python313\site-packages\podman_compose.py

from expandvars import expandvars

container_to_args():
    env = [expandvars(v) for v in env]

Discarded attempted fix: env = {k: expandvars(v) for k, v in env.items()}

[jorgehermo9]

I have found the same issue.

to reproduce, the following compose file:

services:
  postgres:
    image: docker.io/postgres:${CONFIG_VERSION}
    command: /postgres-init.sh
    volumes:
    - socket:/var/run/postgresql
    - ../../../tests/data/postgres-init.sh:/postgres-init.sh:ro
    - ../../../tests/data/ca:/certs:ro
    environment:
    - POSTGRES_USER=vector
    - POSTGRES_PASSWORD=vector
volumes:
  socket: {}
networks:
  default:
    external: 'true'
    name: vector-integration-tests-postgres

and execute export CONFIG_VERSION=13.1.

podman compose up fails while docker compose up runs successfully. The env vars are not interpolated into the compose file

The following error is shown:

Traceback (most recent call last):
  File "/usr/bin/podman-compose", line 8, in <module>
    sys.exit(main())
             ~~~~^^
  File "/usr/lib/python3.13/site-packages/podman_compose.py", line 3711, in main
    asyncio.run(async_main())
    ~~~~~~~~~~~^^^^^^^^^^^^^^
  File "/usr/lib/python3.13/asyncio/runners.py", line 194, in run
    return runner.run(main)
           ~~~~~~~~~~^^^^^^
  File "/usr/lib/python3.13/asyncio/runners.py", line 118, in run
    return self._loop.run_until_complete(task)
           ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^^^^^^
  File "/usr/lib/python3.13/asyncio/base_events.py", line 720, in run_until_complete
    return future.result()
           ~~~~~~~~~~~~~^^
  File "/usr/lib/python3.13/site-packages/podman_compose.py", line 3707, in async_main
    await podman_compose.run()
  File "/usr/lib/python3.13/site-packages/podman_compose.py", line 1861, in run
    retcode = await cmd(self, args)
              ^^^^^^^^^^^^^^^^^^^^^
  File "/usr/lib/python3.13/site-packages/podman_compose.py", line 2702, in compose_up
    podman_args = await container_to_args(compose, cnt, detached=args.detach)
                  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/lib/python3.13/site-packages/podman_compose.py", line 1099, in container_to_args
    podman_args.extend(get_net_args(compose, cnt))
                       ~~~~~~~~~~~~^^^^^^^^^^^^^^
  File "/usr/lib/python3.13/site-packages/podman_compose.py", line 934, in get_net_args
    return get_net_args_from_networks(compose, cnt)
  File "/usr/lib/python3.13/site-packages/podman_compose.py", line 983, in get_net_args_from_networks
    net_name = ext_desc.get("name") or net_desc.get("name") or default_net_name
               ^^^^^^^^^^^^
AttributeError: 'str' object has no attribute 'get

I think the error message could be improved, as it did not say anything about unresolved environment vars (I found #1067 before reaching this issue)

[d-air1]

Also present on Arch, downgrading to 1.2.0 for now solves the issue. Error message could definitely be improved. It was certainly a surprise that a previously working docker-compose.yml stopped working. The only reason I didn't notice earlier is because I hadn't needed to update my container images in a while.

[d-air1]

ping