docker_swarm_service_info: Read information about swarm services (#55008)

* Add docker_swarm_service_info module

* Remove unused import

* Limit to retrieving info about one service

* Add exists return value

* Add yaml 3-dash

Co-Authored-By: hannseman <hannes@5monkeys.se>

* Document return value as jinja `none´

Co-Authored-By: hannseman <hannes@5monkeys.se>

* Name is required

lib/ansible/module_utils/docker/swarm.py

@@ -4,7 +4,6 @@
 
 import json
 from time import sleep
-from re import split
 
 try:
     from docker.errors import APIError
@@ -249,3 +248,29 @@ class AnsibleDockerSwarmClient(AnsibleDockerClient):
         if self.docker_py_version < LooseVersion('2.7.0'):
             return None
         return super(AnsibleDockerSwarmClient, self).get_unlock_key()
+
+    def get_service_inspect(self, service_id, skip_missing=False):
+        """
+        Returns Swarm service info as in 'docker service inspect' command about single service
+
+        :param service_id: service ID or name
+        :param skip_missing: if True then function will return None instead of failing the task
+        :return:
+            Single service information structure
+        """
+        try:
+            service_info = self.inspect_service(service=service_id)
+        except APIError as exc:
+            if exc.status_code == 503:
+                self.fail("Cannot inspect service: To inspect service execute module on Swarm Manager")
+            if exc.status_code == 404:
+                if skip_missing is False:
+                    self.fail("Error while reading from Swarm manager: %s" % to_native(exc))
+                else:
+                    return None
+        except Exception as exc:
+            self.fail("Error inspecting swarm service: %s" % exc)
+
+        json_str = json.dumps(service_info, ensure_ascii=False)
+        service_info = json.loads(json_str)
+        return service_info

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

@@ -0,0 +1,104 @@
+#!/usr/bin/python
+#
+# (c) 2019 Hannes Ljungberg <hannes.ljungberg@gmail.com>
+# GNU General Public License v3.0+ (see COPYING or https://www.gnu.org/licenses/gpl-3.0.txt)
+
+from __future__ import absolute_import, division, print_function
+__metaclass__ = type
+
+
+ANSIBLE_METADATA = {
+    'metadata_version': '1.1',
+    'status': ['preview'],
+    'supported_by': 'community'
+}
+
+DOCUMENTATION = '''
+---
+module: docker_swarm_service_info
+
+short_description: Retrieves information about docker services from a Swarm Manager
+
+description:
+  - Retrieves information about a docker service.
+  - Essentially returns the output of C(docker service inspect <name>).
+  - Must be executed on a host running as Swarm Manager, otherwise the module will fail.
+
+version_added: "2.8"
+
+options:
+  name:
+    description:
+      - The name of the service to inspect.
+    type: str
+    required: yes
+extends_documentation_fragment:
+  - docker
+  - docker.docker_py_1_documentation
+
+author:
+  - Hannes Ljungberg (@hannseman)
+
+requirements:
+  - "L(Docker SDK for Python,https://docker-py.readthedocs.io/en/stable/) >= 2.0.0"
+  - "Docker API >= 1.24"
+'''
+
+EXAMPLES = '''
+- name: Get info from a service
+  docker_swarm_service_info:
+    name: myservice
+  register: result
+'''
+
+RETURN = '''
+exists:
+    description:
+      - Returns whether the service exists.
+    type: bool
+    returned: always
+    sample: true
+service:
+    description:
+      - A dictionary representing the current state of the service. Matches the C(docker service inspect) output.
+      - Will be C(none) if service does not exist.
+    returned: always
+    type: dict
+'''
+
+from ansible.module_utils.docker.swarm import AnsibleDockerSwarmClient
+
+
+def get_service_info(client):
+    service = client.module.params['name']
+    return client.get_service_inspect(
+        service_id=service,
+        skip_missing=True
+    )
+
+
+def main():
+    argument_spec = dict(
+        name=dict(type='str', required=True),
+    )
+
+    client = AnsibleDockerSwarmClient(
+        argument_spec=argument_spec,
+        supports_check_mode=True,
+        min_docker_version='2.0.0',
+        min_docker_api_version='1.24',
+    )
+
+    client.fail_task_if_not_swarm_manager()
+
+    service = get_service_info(client)
+
+    client.module.exit_json(
+        changed=False,
+        service=service,
+        exists=bool(service)
+    )
+
+
+if __name__ == '__main__':
+    main()

test/integration/targets/docker_swarm_service_info/aliases

@@ -0,0 +1,7 @@
+shippable/posix/group3
+skip/osx
+skip/freebsd
+destructive
+skip/docker  # The tests sometimes make docker daemon unstable; hence,
+             # we skip all docker-based CI runs to avoid disrupting
+             # the whole CI system.

test/integration/targets/docker_swarm_service_info/meta/main.yml

@@ -0,0 +1,3 @@
+---
+dependencies:
+  - setup_docker

test/integration/targets/docker_swarm_service_info/tasks/main.yml

@@ -0,0 +1,6 @@
+---
+- include_tasks: test_docker_swarm_service_info.yml
+  when: docker_py_version is version('2.0.0', '>=') and docker_api_version is version('1.24', '>=')
+
+- fail: msg="Too old docker / docker-py version to run docker_swarm_service_info tests!"
+  when: not(docker_py_version is version('2.0.0', '>=') and docker_api_version is version('1.24', '>=')) and (ansible_distribution != 'CentOS' or ansible_distribution_major_version|int > 6)

test/integration/targets/docker_swarm_service_info/tasks/test_docker_swarm_service_info.yml

@@ -0,0 +1,76 @@
+---
+
+- name: Generate service base name
+  set_fact:
+    service_base_name: "{{ 'ansible-test-%0x' % ((2**32) | random) }}"
+
+- name: Registering service names
+  set_fact:
+    service_name: "{{ service_base_name ~ '-1' }}"
+
+- block:
+  - name: Make sure we're not already using Docker swarm
+    docker_swarm:
+      state: absent
+      force: true
+
+  - name: Try to get docker_swarm_service_info when docker is not running in swarm mode
+    docker_swarm_service_info:
+      name: "{{ service_name }}"
+    ignore_errors: yes
+    register: output
+
+  - name: assert failure when called when swarm is not in use or not run on manager node
+    assert:
+      that:
+        - 'output is failed'
+        - 'output.msg == "Error running docker swarm module: must run on swarm manager node"'
+
+  - name: Create a Swarm cluster
+    docker_swarm:
+      state: present
+    register: output
+
+  - name: Create services
+    docker_swarm_service:
+      name: "{{ service_name }}"
+      image: alpine:3.8
+
+  - name: Try to get docker_swarm_service_info for a single service
+    docker_swarm_service_info:
+      name: "{{ service_name }}"
+    register: output
+
+  - name: assert reading reading service info
+    assert:
+      that:
+        - 'output.exists == true'
+        - 'output.service.ID is string'
+        - 'output.service.Spec.Name == service_name'
+
+  - name: Create random name
+    set_fact:
+      random_service_name: "{{ 'random-service-%0x' % ((2**32) | random) }}"
+
+  - name: Try to get docker_swarm_service_info using random service name as parameter
+    docker_swarm_service_info:
+      name: "{{ random_service_name }}"
+    register: output
+
+  - name: assert reading reading service info
+    assert:
+      that:
+        - 'output.service is none'
+        - 'output.exists == false'
+
+  always:
+    - name: Remove services
+      docker_swarm_service:
+        name: "{{ service_name }}"
+        state: absent
+      ignore_errors: yes
+
+    - name: Remove swarm
+      docker_swarm:
+        state: absent
+        force: true