Molecule 3.2.0a0 fails when /bin/bash does not exist

[sio]

Issue Type

• Bug report

Molecule and Ansible details

molecule 3.2.0a0
    ansible:2.10.2 python:3.8
    delegated:3.2.0a0 from molecule
    docker:0.3.3 from molecule_docker
    vagrant:0.5 from molecule_vagrant
/builds/sio/server_common/venv/bin/ansible --version
ansible 2.10.2
  config file = None
  configured module search path = ['/root/.ansible/plugins/modules', '/usr/share/ansible/plugins/modules']
  ansible python module location = /builds/sio/server_common/venv/lib/python3.8/site-packages/ansible
  executable location = /builds/sio/server_common/venv/bin/ansible
  python version = 3.8.5 (default, Jul 20 2020, 23:11:29) [GCC 9.3.0]

Molecule installation method (one of):

• pip

Ansible installation method (one of):

• pip

Detail any linters or test runners used:

set -e
yamllint .
ansible-lint

Desired Behavior

Molecule does not crash when /bin/bash is not installed. /bin/sh should be good enough.

Actual Behaviour

Molecule (with docker plugin) crashes in docker sanity check stage. It tries to execute /bin/bash even when it's not installed, which results in an unhandled FileNotFoundError:

--> Sanity checks: 'docker'
Traceback (most recent call last):
  File "/builds/sio/server_common/venv/bin/molecule", line 8, in <module>
    sys.exit(main())
  File "/builds/sio/server_common/venv/lib/python3.8/site-packages/click/core.py", line 829, in __call__
    return self.main(*args, **kwargs)
  File "/builds/sio/server_common/venv/lib/python3.8/site-packages/click/core.py", line 782, in main
    rv = self.invoke(ctx)
  File "/builds/sio/server_common/venv/lib/python3.8/site-packages/click/core.py", line 1259, in invoke
    return _process_result(sub_ctx.command.invoke(sub_ctx))
  File "/builds/sio/server_common/venv/lib/python3.8/site-packages/click/core.py", line 1066, in invoke
    return ctx.invoke(self.callback, **ctx.params)
  File "/builds/sio/server_common/venv/lib/python3.8/site-packages/click/core.py", line 610, in invoke
    return callback(*args, **kwargs)
  File "/builds/sio/server_common/venv/lib/python3.8/site-packages/click/decorators.py", line 21, in new_func
    return f(get_current_context(), *args, **kwargs)
  File "/builds/sio/server_common/venv/lib/python3.8/site-packages/molecule/command/test.py", line 148, in test
    base.execute_cmdline_scenarios(scenario_name, args, command_args)
  File "/builds/sio/server_common/venv/lib/python3.8/site-packages/molecule/command/base.py", line 104, in execute_cmdline_scenarios
    execute_scenario(scenario)
  File "/builds/sio/server_common/venv/lib/python3.8/site-packages/molecule/command/base.py", line 146, in execute_scenario
    execute_subcommand(scenario.config, action)
  File "/builds/sio/server_common/venv/lib/python3.8/site-packages/molecule/command/base.py", line 135, in execute_subcommand
    return command(config).execute()
  File "/builds/sio/server_common/venv/lib/python3.8/site-packages/molecule/command/destroy.py", line 108, in execute
    self._config.provisioner.destroy()
  File "/builds/sio/server_common/venv/lib/python3.8/site-packages/molecule/provisioner/ansible.py", line 702, in destroy
    pb.execute()
  File "/builds/sio/server_common/venv/lib/python3.8/site-packages/molecule/provisioner/ansible_playbook.py", line 107, in execute
    result = util.run_command(self._ansible_command, debug=self._config.debug)
  File "/builds/sio/server_common/venv/lib/python3.8/site-packages/molecule/util.py", line 151, in run_command
    return run(args, env=env, stdout=stdout, stderr=stderr, echo=echo or debug)
  File "/builds/sio/server_common/venv/lib/python3.8/site-packages/subprocess_tee/__init__.py", line 88, in run
    result = loop.run_until_complete(_stream_subprocess(cmd, **kwargs))
  File "/usr/lib/python3.8/asyncio/base_events.py", line 616, in run_until_complete
    return future.result()
  File "/builds/sio/server_common/venv/lib/python3.8/site-packages/subprocess_tee/__init__.py", line 32, in _stream_subprocess
    process = await asyncio.create_subprocess_shell(
  File "/usr/lib/python3.8/asyncio/subprocess.py", line 216, in create_subprocess_shell
    transport, protocol = await loop.subprocess_shell(
  File "/usr/lib/python3.8/asyncio/base_events.py", line 1597, in subprocess_shell
    transport = await self._make_subprocess_transport(
  File "/usr/lib/python3.8/asyncio/unix_events.py", line 197, in _make_subprocess_transport
    transp = _UnixSubprocessTransport(self, protocol, args, shell,
  File "/usr/lib/python3.8/asyncio/base_subprocess.py", line 36, in __init__
    self._start(args=args, shell=shell, stdin=stdin, stdout=stdout,
  File "/usr/lib/python3.8/asyncio/unix_events.py", line 789, in _start
    self._proc = subprocess.Popen(
  File "/usr/lib/python3.8/subprocess.py", line 854, in __init__
    self._execute_child(args, executable, preexec_fn, close_fds,
  File "/usr/lib/python3.8/subprocess.py", line 1702, in _execute_child
    raise child_exception_type(errno_num, err_msg, err_filename)
FileNotFoundError: [Errno 2] No such file or directory: '/bin/bash'

Full log: https://gitlab.com/sio/server_common/-/jobs/823643538

Molecule 3.1.5 worked fine on the same runner (without /bin/bash).

[ssbarnea]

What changed in-between was switching from sh to subprocess_tee library and considering that molecule does not specify any shell itself, this is an upstream bug. Please raise it at https://github.com/pycontribs/subprocess-tee/issues and as soon we fix it I will update molecule to require a version of subprocess-tee that has the fix in it.

It is not unreasonable to assume that some platforms may not have bash as default shell.

[sio]

subprocess-tee >= 0.1.3 works fine! Thank you very much!