Podman support?

[kianmeng]

While running the test, I have noticed this library only support Docker. Are there any plans to support https://github.com/containers/podman?

$ mix test
Compiling 34 files (.ex)
** (EXIT from #PID<0.99.0>) an exception was raised:
    ** (CaseClauseError) no case clause matching: {:error, [docker_socket_path: :docker_socket_not_found]}
        (testcontainers 1.6.0) lib/connection/connection.ex:34: Testcontainers.Connection.docker_base_url/0
        (testcontainers 1.6.0) lib/connection/connection.ex:16: Testcontainers.Connection.get_connection/1
        (testcontainers 1.6.0) lib/testcontainers.ex:33: Testcontainers.setup/1
        (stdlib 5.2) gen_server.erl:980: :gen_server.init_it/2
        (stdlib 5.2) gen_server.erl:935: :gen_server.init_it/6
        (stdlib 5.2) proc_lib.erl:241: :proc_lib.init_p_do_apply/3

[jarlah]

My immediate thought is that this should "just work". But i suppose it suffers from the same issue as the other implementations where you have to define the docker_host env var to point to podman socket.

[kiview]

@kianmeng What happens if you configure Podman as proposed by @jarlah? In general, all Testcontainers libraries always expect a Docker Engine API, that's is against what we integrate and if things fail, this would be an upstream issue with Podman behaving differently than Docker.

[kianmeng]

@kiview Not working for me.

ENV:

elixir          1.16.3-otp-26   /tmp/testcontainers-elixir/.tool-versions
erlang          26.2.5          /tmp/elixir/testcontainers-elixir/.tool-versions

Steps to reproduce:

cd /tmp
git clone https://github.com/testcontainers/testcontainers-elixir
cd testcontainers-elixir
asdf local elixir 1.16.3-otp-26
asdf local erlang 26.2.5
mix deps.get
export DOCKER_HOST=unix://$XDG_RUNTIME_DIR/podman/podman.sock
mix test

Result:

...
01:01:35.747 [warning] Using docker host url: http+unix://%2Fvar%2Frun%2Fdocker.sock/v1.41

01:01:46.916 [warning] Not running in docker environment, using localhost

01:01:46.916 [warning] Testcontainers initialized
.....
01:01:47.072 [warning] Using docker host url: http+unix://%2Fvar%2Frun%2Fdocker.sock/v1.41
.............
01:01:52.574 [warning] Not running in docker environment, using localhost

01:01:52.574 [warning] Testcontainers initialized

  1) test can start and stop generic container (Testcontainers.GenericContainerTest)                                                      
     test/generic_container_test.exs:4                                                                                                    
     ** (ExUnit.TimeoutError) test timed out after 60000ms. You can change the timeout:                                                   
                                                                     
       1. per test by setting "@tag timeout: x" (accepts :infinity)                                                                       
       2. per test module by setting "@moduletag timeout: x" (accepts :infinity)
       3. globally via "ExUnit.start(timeout: x)" configuration
       4. by running "mix test --timeout x" which sets timeout
       5. or by running "mix test --trace" which sets timeout to infinity
          (useful when using IEx.pry/0)

     where "x" is the timeout given as integer in milliseconds (defaults to 60_000).
     
     code: assert {:ok, container} = Testcontainers.start_container(config)
     stacktrace:
       (stdlib 5.2.3) gen.erl:259: :gen.do_call/4
       (elixir 1.16.3) lib/gen_server.ex:1111: GenServer.call/3
       test/generic_container_test.exs:6: (test)
       (ex_unit 1.16.3) lib/ex_unit/runner.ex:472: ExUnit.Runner.exec_test/2
       (stdlib 5.2.3) timer.erl:270: :timer.tc/2
       (ex_unit 1.16.3) lib/ex_unit/runner.ex:394: anonymous fn/6 in ExUnit.Runner.spawn_test_monitor/4
...

[jarlah]

I think it might be test_docker_host that messes things up. It tries to do a ping to test the connection. So it would never work with podman I guess, because it doesn't work that way. I would need, or someone else, to look into how the docker host is tested in the strategy implementations. I will look into it in due time, but this could be a good hint for someone else to start working on, the method test_docker_host

[jarlah]

adding good first issue, since this is a localized issue and can be solved in isolation.

[jarlah]

Should port this

https://github.com/testcontainers/testcontainers-go/blob/main/internal/core/docker_rootless.go

i suppose we are only implementing the stuff we can see in

https://github.com/testcontainers/testcontainers-go/blob/main/internal/core/docker_host.go

[jarlah]

we only support docker host urls that can reply to /_ping which propably doesnt include rootless podman urls