Rewrite the docker_containers inventory plugin (#413)

* Rewrite the docker_containers inventory plugin.

* Improve error messages.

changelogs/fragments/413-docker-api.yml

@@ -0,0 +1,4 @@
+major_changes:
+  - "docker_containers inventory plugin - no longer uses the Docker SDK for Python. It requires ``requests`` to be installed,
+     and depending on the features used has some more requirements. If the Docker SDK for Python is installed,
+     these requirements are likely met (https://github.com/ansible-collections/community.docker/pull/413)."

plugins/inventory/docker_containers.py

@@ -17,12 +17,9 @@ short_description: Ansible dynamic inventory plugin for Docker containers.
 version_added: 1.1.0
 author:
     - Felix Fontein (@felixfontein)
-requirements:
-    - L(Docker SDK for Python,https://docker-py.readthedocs.io/en/stable/) >= 1.10.0
 extends_documentation_fragment:
     - ansible.builtin.constructed
-    - community.docker.docker
-    - community.docker.docker.docker_py_1_documentation
+    - community.docker.docker.api_documentation
 description:
     - Reads inventories from the Docker API.
     - Uses a YAML configuration file that ends with C(docker.[yml|yaml]).
@@ -154,23 +151,18 @@ from ansible.errors import AnsibleError
 from ansible.module_utils.common.text.converters import to_native
 from ansible.plugins.inventory import BaseInventoryPlugin, Constructable
 
-from ansible_collections.community.docker.plugins.module_utils.common import (
+from ansible_collections.community.docker.plugins.module_utils.common_api import (
     RequestException,
 )
 from ansible_collections.community.docker.plugins.module_utils.util import (
     DOCKER_COMMON_ARGS_VARS,
 )
-from ansible_collections.community.docker.plugins.plugin_utils.common import (
+from ansible_collections.community.docker.plugins.plugin_utils.common_api import (
     AnsibleDockerClient,
 )
 
-try:
-    from docker.errors import DockerException, APIError
-except Exception:
-    # missing Docker SDK for Python handled in ansible_collections.community.docker.plugins.module_utils.common
-    pass
+from ansible_collections.community.docker.plugins.module_utils._api.errors import APIError, DockerException
 
-MIN_DOCKER_PY = '1.7.0'
 MIN_DOCKER_API = None
 
 
@@ -193,7 +185,15 @@ class InventoryModule(BaseInventoryPlugin, Constructable):
         add_legacy_groups = self.get_option('add_legacy_groups')
 
         try:
-            containers = client.containers(all=True)
+            params = {
+                'limit': -1,
+                'all': 1,
+                'size': 0,
+                'trunc_cmd': 0,
+                'since': None,
+                'before': None,
+            }
+            containers = client.get_json('/containers/json', params=params)
         except APIError as exc:
             raise AnsibleError("Error listing containers: %s" % to_native(exc))
 
@@ -227,7 +227,7 @@ class InventoryModule(BaseInventoryPlugin, Constructable):
             full_facts = dict()
 
             try:
-                inspect = client.inspect_container(id)
+                inspect = client.get_json('/containers/{0}/json', id)
             except APIError as exc:
                 raise AnsibleError("Error inspecting container %s - %s" % (name, str(exc)))
 
@@ -261,7 +261,9 @@ class InventoryModule(BaseInventoryPlugin, Constructable):
                 # Figure out ssh IP and Port
                 try:
                     # Lookup the public facing port Nat'ed to ssh port.
-                    port = client.port(container, ssh_port)[0]
+                    network_settings = inspect.get('NetworkSettings') or {}
+                    port_settings = network_settings.get('Ports') or {}
+                    port = port_settings.get('%d/tcp' % (ssh_port, ))[0]
                 except (IndexError, AttributeError, TypeError):
                     port = dict()
 
@@ -330,7 +332,7 @@ class InventoryModule(BaseInventoryPlugin, Constructable):
             path.endswith(('docker.yaml', 'docker.yml')))
 
     def _create_client(self):
-        return AnsibleDockerClient(self, min_docker_version=MIN_DOCKER_PY, min_docker_api_version=MIN_DOCKER_API)
+        return AnsibleDockerClient(self, min_docker_api_version=MIN_DOCKER_API)
 
     def parse(self, inventory, loader, path, cache=True):
         super(InventoryModule, self).parse(inventory, loader, path, cache)
@@ -340,9 +342,9 @@ class InventoryModule(BaseInventoryPlugin, Constructable):
             self._populate(client)
         except DockerException as e:
             raise AnsibleError(
-                'An unexpected docker error occurred: {0}'.format(e)
+                'An unexpected Docker error occurred: {0}'.format(e)
             )
         except RequestException as e:
             raise AnsibleError(
-                'An unexpected requests error occurred when Docker SDK for Python tried to talk to the docker daemon: {0}'.format(e)
+                'An unexpected requests error occurred when trying to talk to the Docker daemon: {0}'.format(e)
             )

tests/unit/plugins/inventory/test_docker_containers.py

@@ -93,29 +93,22 @@ def create_get_option(options, default=False):
 
 class FakeClient(object):
     def __init__(self, *hosts):
-        self.hosts = dict()
-        self.list_reply = []
+        self.get_results = {}
+        list_reply = []
         for host in hosts:
-            self.list_reply.append({
+            list_reply.append({
                 'Id': host['Id'],
                 'Names': [host['Name']] if host['Name'] else [],
                 'Image': host['Config']['Image'],
                 'ImageId': host['Image'],
             })
-            self.hosts[host['Name']] = host
-            self.hosts[host['Id']] = host
+            self.get_results['/containers/{0}/json'.format(host['Name'])] = host
+            self.get_results['/containers/{0}/json'.format(host['Id'])] = host
+        self.get_results['/containers/json'] = list_reply
 
-    def containers(self, all=False):
-        return list(self.list_reply)
-
-    def inspect_container(self, id):
-        return self.hosts[id]
-
-    def port(self, container, port):
-        host = self.hosts[container['Id']]
-        network_settings = host.get('NetworkSettings') or dict()
-        ports = network_settings.get('Ports') or dict()
-        return ports.get('{0}/tcp'.format(port)) or []
+    def get_json(self, url, *param, **kwargs):
+        url = url.format(*param)
+        return self.get_results[url]
 
 
 def test_populate(inventory, mocker):