check mode: docker_puppet_tasks

Adds check mode support for docker_puppet_tasks.

Since it's not possible to reliably determine what these tasks do, we
can't actually run them to get an idea of what might be changed. We can
however show the diff of the json file to get an idea of what would be
run.

Change-Id: I19e8bc9eb93d8acc8ee7d737770f9cc7e63f7a27

common/deploy-steps-tasks.yaml

@@ -97,6 +97,7 @@
             selevel: s0
           tags:
             - container_config
+            - container_config_tasks
 
         - name: Delete existing /var/lib/docker-puppet/check-mode for check mode
           file:
@@ -277,7 +278,7 @@
 
         - name: Write docker-puppet-tasks json files
           copy:
-            content: "{{item[1]|to_json}}"
+            content: "{{item[1]|to_nice_json}}"
             dest: /var/lib/docker-puppet/docker-puppet-tasks{{item[0].replace("step_", "")}}.json
             force: yes
             mode: '0600'
@@ -410,8 +411,9 @@
         - container_config
 
     - name: Diff docker-puppet.py puppet-generated changes for check mode
-      command:
-        diff -ruN /var/lib/config-data/puppet-generated /var/lib/config-data/check-mode/puppet-generated
+      shell: |
+        diff -ruN --no-dereference -q /var/lib/config-data/puppet-generated /var/lib/config-data/check-mode/puppet-generated
+        diff -ruN --no-dereference /var/lib/config-data/puppet-generated /var/lib/config-data/check-mode/puppet-generated
       register: diff_results
       tags:
         - container_config
@@ -469,7 +471,7 @@
 
     - name: Check if /var/lib/docker-puppet/docker-puppet-tasks{{ step }}.json exists
       stat:
-        path: /var/lib/docker-puppet/docker-puppet-tasks{{ step }}.json
+        path: /var/lib/docker-puppet/{{ ansible_check_mode | ternary('check-mode/', '') }}docker-puppet-tasks{{ step }}.json
       register: docker_puppet_tasks_json
       tags:
         - container_config_tasks
@@ -477,7 +479,8 @@
     - name: Run docker-puppet tasks (bootstrap tasks) for step {{ step }}
       shell: python /var/lib/docker-puppet/docker-puppet.py
       environment:
-        CONFIG: /var/lib/docker-puppet/docker-puppet-tasks{{ step }}.json
+        CONFIG: /var/lib/docker-puppet/{{ ansible_check_mode | ternary('check-mode/', '') }}docker-puppet-tasks{{ step }}.json
+        CONFIG_VOLUME_PREFIX: '/var/lib/config-data{{ ansible_check_mode | ternary("/check-mode", "") }}'
         NET_HOST: "true"
         NO_ARCHIVE: "true"
         STEP: "{{ step }}"
@@ -486,7 +489,6 @@
         - deploy_server_id == bootstrap_server_id
         - docker_puppet_tasks_json.stat.exists
       changed_when: false
-      check_mode: no
       register: outputs
       failed_when: false
       no_log: true