Add 'report_diff' key in result data in case of available diff data

In case that a 'diff' key with 'before' and 'after' data is available
create a unified diff from 'before' and 'after' and store below the
'report_diff' key as a string for later consumption in config reports
on the Foreman server.
Remove the 'diff' key afterwards to save space as it contains the full
contents of the saved file before and after the change.

Signed-off-by: Ruediger Pluem <[email protected]>

plugins/callback/foreman.py

@@ -110,6 +110,7 @@
 from collections import defaultdict
 import json
 import time
+import difflib
 
 try:
     import requests
@@ -122,6 +123,16 @@
 from ansible.module_utils.parsing.convert_bool import boolean as to_bool
 from ansible.plugins.callback import CallbackBase
 
+def create_report_diff(diff_data):
+    """
+    Create a unified diff string from the contents of the file before and
+    after the change.
+    """
+    before = diff_data['before'].splitlines(True)
+    after = diff_data['after'].splitlines(True)
+    diff = difflib.unified_diff(before, after, formfile=diff_data['before_header'],
+                                tofile=diff_data['after_header'])
+    return ''.join(diff)
 
 def build_log_foreman(data_list):
     """
@@ -140,6 +151,16 @@ def build_log_foreman(data_list):
         else:
             level = 'info'
 
+        # Check is the 'diff' key is set and its sub data structure is as
+        # expected. In this case transform the contents of the file before
+        # and after the change into a unified diff string and store it
+        # below the 'report_diff' key. Remove the 'diff' key afterwards
+        # as the content of a file is probably big.
+        if (('diff' in result) and isinstance(result['diff'], list) and
+                result['diff'] and isinstance(result['diff'][0], dict)):
+            result['report_diff'] = create_report_diff(result['diff'][0])
+            del result['diff']
+
         yield {
             "log": {
                 'sources': {