docker_container_exec: improve handling of chdir option (#243)

* Only pass chdir on when it is provided, and prevent this option from being used for Docker SDK for Python < 3.0.0.

* Also fix docker_api connection plugin.

changelogs/fragments/243-docker_container_exec-chdir.yml

@@ -0,0 +1,3 @@
+bugfixes:
+  - "docker_container_exec - ``chdir`` is only supported since Docker SDK for Python 3.0.0. Make sure that this option can only use when 3.0.0 or later is installed, and prevent passing this parameter on when ``chdir`` is not provided to this module (https://github.com/ansible-collections/community.docker/pull/243, https://github.com/ansible-collections/community.docker/issues/242)."
+  - "docker_api connection plugin - avoid passing an unnecessary argument to a Docker SDK for Python call that is only supported by version 3.0.0 or later (https://github.com/ansible-collections/community.docker/pull/243)."

plugins/connection/docker_api.py

@@ -164,7 +164,7 @@ def exec_command(self, cmd, in_data=None, sudoable=False):
             stderr=True,
             stdin=need_stdin,
             user=self._play_context.remote_user or '',
-            workdir=None,
+            # workdir=None,  - only works for Docker SDK for Python 3.0.0 and later
         ))
         exec_id = exec_data['Id']
 

plugins/modules/docker_container_exec.py

@@ -163,8 +163,13 @@ def main():
         tty=dict(type='bool', default=False),
     )
 
+    option_minimal_versions = dict(
+        chdir=dict(docker_py_version='3.0.0'),
+    )
+
     client = AnsibleDockerClient(
         argument_spec=argument_spec,
+        option_minimal_versions=option_minimal_versions,
         min_docker_api_version='1.20',
         mutually_exclusive=[('argv', 'command')],
         required_one_of=[('argv', 'command')],
@@ -190,14 +195,17 @@ def main():
         selectors = find_selectors(client.module)
 
     try:
+        kwargs = {}
+        if chdir is not None:
+            kwargs['workdir'] = chdir
         exec_data = client.exec_create(
             container,
             argv,
             stdout=True,
             stderr=True,
             stdin=bool(stdin),
             user=user or '',
-            workdir=chdir,
+            **kwargs
         )
         exec_id = exec_data['Id']