New docker_stack_module with tests (#576)

* First docker stack info approach without tests

Fixes results when no stack availabl

Fixes sanity test

Fixing links

Fixes tabs

Fixes long line

Improving Json Output

Changes arguments

Lint with autopep8

Moves imports

Adds extra line

Adds Tests

Adds pip and fixes return empty

Fixes silly missing else

* Adds Tests and Fixes comments

* Removes tasks option

* Removes arguments

* Changes error message

* Changes Tests

* Add proposals f

* Improve output

* Change test for output change

* Add debug

plugins/modules/cloud/docker/docker_stack_info.py

@@ -0,0 +1,84 @@
+#!/usr/bin/python
+# -*- coding: utf-8 -*-
+
+# Copyright (c) 2020 Jose Angel Munoz (@imjoseangel)
+# 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
+
+DOCUMENTATION = '''
+---
+module: docker_stack_info
+author: "Jose Angel Munoz (@imjoseangel)"
+short_description: Return information on a docker stack
+description:
+  - Retrieve information on docker stacks using the C(docker stack) command
+    on the target node (see examples).
+version_added: "1.0.0"
+'''
+
+RETURN = '''
+results:
+    description: |
+        List of dictionaries containing the list of stacks or tasks associated
+        to a stack name.
+    sample: >
+        "results": [{"name":"grafana","namespace":"default","orchestrator":"Kubernetes","services":"2"}]
+    returned: always
+    type: list
+'''
+
+EXAMPLES = '''
+  - name: Shows stack info
+    community.general.docker_stack_info:
+    register: result
+
+  - name: Show results
+    ansible.builtin.debug:
+      var: result.results
+'''
+
+import json
+from ansible.module_utils.basic import AnsibleModule
+
+
+def docker_stack_list(module):
+    docker_bin = module.get_bin_path('docker', required=True)
+    rc, out, err = module.run_command(
+        [docker_bin, "stack", "ls", "--format={{json .}}"])
+
+    return rc, out.strip(), err.strip()
+
+
+def main():
+    module = AnsibleModule(
+        argument_spec={
+        },
+        supports_check_mode=False
+    )
+
+    rc, out, err = docker_stack_list(module)
+
+    if rc != 0:
+        module.fail_json(msg="Error running docker stack. {0}".format(err),
+                         rc=rc, stdout=out, stderr=err)
+    else:
+        if out:
+            ret = list(
+                json.loads(outitem)
+                for outitem in out.splitlines())
+
+        else:
+            ret = []
+
+        module.exit_json(changed=False,
+                         rc=rc,
+                         stdout=out,
+                         stderr=err,
+                         results=ret)
+
+
+if __name__ == "__main__":
+    main()