WIP quick-n-dirty aggregate similar failures

If a failure happened in multiple hosts, group them all into a single
summary item.

roles/openshift_health_checker/callback_plugins/zz_failure_summary.py

@@ -8,6 +8,7 @@
 # Status: disabled permanently or until Ansible object has a public API.
 # This does leave the code more likely to be broken by future Ansible changes.
 
+from collections import defaultdict
 from pprint import pformat
 
 from ansible.plugins.callback import CallbackBase
@@ -57,6 +58,22 @@ def _print_failure_details(self, failures):
         subsequent_indent = u' ' * initial_indent_len
         subsequent_extra_indent = u' ' * (initial_indent_len + 10)
 
+        failures = [prepare_failure(failure['result']) for failure in failures]
+
+        d = defaultdict(list)
+        for failure in failures:
+            key = (failure['msg'], failure['play'], failure['task'])
+            d[key].append(failure)
+
+        r = []
+        for failure in failures:
+            key = (failure['msg'], failure['play'], failure['task'])
+            if not d[key]:
+                continue
+            failure['host'] = sorted(f['host'] for f in d.pop(key))
+            r.append(failure)
+        failures = r
+
         for i, failure in enumerate(failures, 1):
             entries = _format_failure(failure)
             self._display.display(u'\n{}{}'.format(initial_indent_format.format(i), entries[0]))
@@ -70,10 +87,10 @@ def _print_failure_details(self, failures):
         # re: result attrs see top comment  # pylint: disable=protected-access
         for failure in failures:
             # get context from check task result since callback plugins cannot access task vars
-            playbook_context = playbook_context or failure['result']._result.get('playbook_context')
+            playbook_context = failure['playbook_context']
             failed_checks.update(
                 name
-                for name, result in failure['result']._result.get('checks', {}).items()
+                for name, result in failure['checks'].items()
                 if result.get('failed')
             )
         if failed_checks:
@@ -109,26 +126,33 @@ def _print_check_failure_summary(self, failed_checks, context):
         self._display.display(summary)
 
 
+def prepare_failure(failure):
+    return {
+        'host': failure._host.get_name(),
+        'play': play_name(failure._task),
+        'task': failure._task.get_name(),
+        'msg': failure._result.get('msg', u'none'),
+        'checks': failure._result.get('checks', {}),
+        'playbook_context': failure._result.get('playbook_context'),
+    }
+
 # re: result attrs see top comment  # pylint: disable=protected-access
 def _format_failure(failure):
     '''Return a list of pretty-formatted text entries describing a failure, including
     relevant information about it. Expect that the list of text entries will be joined
     by a newline separator when output to the user.'''
-    result = failure['result']
-    host = result._host.get_name()
-    play = _get_play(result._task)
-    if play:
-        play = play.get_name()
-    task = result._task.get_name()
-    msg = result._result.get('msg', u'???')
+    host = u', '.join(failure['host'])
+    play = failure['play']
+    task = failure['task']
+    msg = failure['msg']
     fields = (
-        (u'Host', host),
+        (u'Hosts', host),
         (u'Play', play),
         (u'Task', task),
         (u'Message', stringc(msg, C.COLOR_ERROR)),
     )
-    if 'checks' in result._result:
-        fields += ((u'Details', _format_failed_checks(result._result['checks'])),)
+    if failure['checks']:
+        fields += ((u'Details', _format_failed_checks(failure['checks'])),)
     row_format = '{:10}{}'
     return [row_format.format(header + u':', body) for header, body in fields]
 
@@ -148,9 +172,10 @@ def _format_failed_checks(checks):
 
 # This is inspired by ansible.playbook.base.Base.dump_me.
 # re: play/task/block attrs see top comment  # pylint: disable=protected-access
-def _get_play(obj):
+def play_name(obj):
     '''Given a task or block, recursively tries to find its parent play.'''
     if hasattr(obj, '_play'):
-        return obj._play
+        return obj._play.get_name()
     if getattr(obj, '_parent'):
-        return _get_play(obj._parent)
+        return play_name(obj._parent)
+    return ''