docker_container: fix check mode for container creation (#42380)

* Create copy of HostConfig object before adding it to results.

* Create general sanitize function in docker_common. Using it for all return values of docker_container.

* Make Python 2.6 compatible.

lib/ansible/module_utils/docker_common.py

@@ -120,6 +120,24 @@ if not HAS_DOCKER_PY:
         pass
 
 
+def sanitize_result(data):
+    """Sanitize data object for return to Ansible.
+
+    When the data object contains types such as docker.types.containers.HostConfig,
+    Ansible will fail when these are returned via exit_json or fail_json.
+    HostConfig is derived from dict, but its constructor requires additional
+    arguments. This function sanitizes data structures by recursively converting
+    everything derived from dict to dict and everything derived from list (and tuple)
+    to a list.
+    """
+    if isinstance(data, dict):
+        return dict((k, sanitize_result(v)) for k, v in data.items())
+    elif isinstance(data, (list, tuple)):
+        return [sanitize_result(v) for v in data]
+    else:
+        return data
+
+
 class DockerBaseClass(object):
 
     def __init__(self):

lib/ansible/modules/cloud/docker/docker_container.py

@@ -634,7 +634,7 @@ import shlex
 from distutils.version import LooseVersion
 
 from ansible.module_utils.basic import human_to_bytes
-from ansible.module_utils.docker_common import HAS_DOCKER_PY_2, HAS_DOCKER_PY_3, AnsibleDockerClient, DockerBaseClass
+from ansible.module_utils.docker_common import HAS_DOCKER_PY_2, HAS_DOCKER_PY_3, AnsibleDockerClient, DockerBaseClass, sanitize_result
 from ansible.module_utils.six import string_types
 
 try:
@@ -1817,7 +1817,7 @@ class ContainerManager(DockerBaseClass):
             self.container_remove(container.Id)
 
     def fail(self, msg, **kwargs):
-        self.client.module.fail_json(msg=msg, **kwargs)
+        self.client.module.fail_json(msg=msg, **sanitize_result(kwargs))
 
     def _output_logs(self, msg):
         self.client.module.log(msg=msg)
@@ -2149,7 +2149,7 @@ def main():
     )
 
     cm = ContainerManager(client)
-    client.module.exit_json(**cm.results)
+    client.module.exit_json(**sanitize_result(cm.results))
 
 
 if __name__ == '__main__':