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

tests/integration/targets/docker_stack_info/tasks/main.yml

@@ -0,0 +1,5 @@
+- include_tasks: test_stack_info.yml
+  when: docker_api_version is version('1.25', '>=')
+
+- fail: msg="Too old docker / docker-py version to run docker_stack tests!"
+  when: not(docker_api_version is version('1.25', '>=')) and (ansible_distribution != 'CentOS' or ansible_distribution_major_version|int > 6)

tests/integration/targets/docker_stack_info/tasks/test_stack_info.yml

@@ -0,0 +1,75 @@
+---
+- block:
+  - name: Make sure we're not already using Docker swarm
+    docker_swarm:
+      state: absent
+      force: true
+
+  - name: Get docker_stack_info when docker is not running in swarm mode
+    docker_stack_info:
+    ignore_errors: true
+    register: output
+
+  - name: Assert failure when called when swarm is not running
+    assert:
+      that:
+        - 'output is failed'
+        - '"Error running docker stack" in output.msg'
+
+  - name: Create a swarm cluster
+    docker_swarm:
+      state: present
+      advertise_addr: "{{ansible_default_ipv4.address}}"
+
+  - name: Get docker_stack_info when docker is running and not stack available
+    docker_stack_info:
+    register: output
+
+  - name: Assert stack facts
+    assert:
+      that:
+        - 'output.results | type_debug == "list"'
+        - 'output.results | length == 0'
+
+  - name: Copy compose files
+    copy:
+      src: "{{ item }}"
+      dest: "{{ output_dir }}/"
+    with_items:
+    - stack_compose_base.yml
+    - stack_compose_overrides.yml
+
+  - name: Install docker_stack python requirements
+    pip:
+      name: jsondiff,pyyaml
+
+  - name: Create stack with compose file
+    register: output
+    docker_stack:
+      state: present
+      name: test_stack
+      compose:
+      - "{{ output_dir }}/stack_compose_base.yml"
+
+  - name: Assert test_stack changed on stack creation with compose file
+    assert:
+      that:
+      - output is changed
+
+  - name: Get docker_stack_info when docker is running
+    docker_stack_info:
+    register: output
+
+  - name: assert stack facts
+    assert:
+      that:
+        - 'output.results | type_debug == "list"'
+        - 'output.results[0].Name == "test_stack"'
+        - 'output.results[0].Orchestrator == "Swarm"'
+        - 'output.results[0].Services == "1"'
+
+  always:
+  - name: Cleanup
+    docker_swarm:
+      state: absent
+      force: true