docker_*: report more warnings (#53710)

* More warnings.

* Add changelog.

* Improve docstring.

changelogs/fragments/53710-docker-warnings.yml

@@ -0,0 +1,3 @@
+bugfixes:
+- "docker_network - now returns warnings from docker daemon on network creation."
+- "docker_swarm_service - now returns warnings from docker daemon on service creation."

lib/ansible/module_utils/docker/common.py

@@ -24,6 +24,7 @@ from distutils.version import LooseVersion
 
 from ansible.module_utils.basic import AnsibleModule, env_fallback
 from ansible.module_utils.common._collections_compat import Mapping, Sequence
+from ansible.module_utils.six import string_types
 from ansible.module_utils.six.moves.urllib.parse import urlparse
 from ansible.module_utils.parsing.convert_bool import BOOLEANS_TRUE, BOOLEANS_FALSE
 
@@ -664,6 +665,15 @@ class AnsibleDockerClient(Client):
     def report_warnings(self, result, warnings_key=None):
         '''
         Checks result of client operation for warnings, and if present, outputs them.
+
+        warnings_key should be a list of keys used to crawl the result dictionary.
+        For example, if warnings_key == ['a', 'b'], the function will consider
+        result['a']['b'] if these keys exist. If the result is a non-empty string, it
+        will be reported as a warning. If the result is a list, every entry will be
+        reported as a warning.
+
+        In most cases (if warnings are returned at all), warnings_key should be
+        ['Warnings'] or ['Warning']. The default value (if not specified) is ['Warnings'].
         '''
         if warnings_key is None:
             warnings_key = ['Warnings']
@@ -674,6 +684,8 @@ class AnsibleDockerClient(Client):
         if isinstance(result, Sequence):
             for warning in result:
                 self.module.warn('Docker warning: {0}'.format(warning))
+        elif isinstance(result, string_types) and result:
+            self.module.warn('Docker warning: {0}'.format(result))
 
 
 def compare_dict_allow_more_present(av, bv):

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

@@ -496,7 +496,7 @@ class DockerNetworkManager(object):
 
             if not self.check_mode:
                 resp = self.client.create_network(self.parameters.network_name, **params)
-
+                self.client.report_warnings(resp, ['Warning'])
                 self.existing_network = self.client.get_network(id=resp['Id'])
             self.results['actions'].append("Created network %s with driver %s" % (self.parameters.network_name, self.parameters.driver))
             self.results['changed'] = True

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

@@ -2255,10 +2255,13 @@ class DockerServiceManager(object):
             name=name,
             **service_data
         )
+        # Unfortunately, docker-py f***ed up and doesn't return the structure
+        # the corresponding API call returns, which would include a list of warnings.
 
     def create_service(self, name, service):
         service_data = service.build_docker_service(self.get_networks_names_ids())
-        self.client.create_service(name=name, **service_data)
+        result = self.client.create_service(name=name, **service_data)
+        self.client.report_warnings(result, ['Warning'])
 
     def remove_service(self, name):
         self.client.remove_service(name)