fixed code for v1 callback runtime compatiblity

old exception code obsoleted by exception avoidance
errors on callback produce warnings and don't stop play

lib/ansible/executor/task_queue_manager.py

@@ -19,7 +19,6 @@
 from __future__ import (absolute_import, division, print_function)
 __metaclass__ = type
 
-from multiprocessing.managers import SyncManager, DictProxy
 import multiprocessing
 import os
 import tempfile
@@ -27,7 +26,6 @@ import tempfile
 from ansible import constants as C
 from ansible.errors import AnsibleError
 from ansible.executor.play_iterator import PlayIterator
-from ansible.executor.process.worker import WorkerProcess
 from ansible.executor.process.result import ResultProcess
 from ansible.executor.stats import AggregateStats
 from ansible.playbook.play_context import PlayContext
@@ -284,18 +282,22 @@ class TaskQueueManager:
             # see osx_say.py example for such a plugin
             if getattr(callback_plugin, 'disabled', False):
                 continue
-            methods = [
-                getattr(callback_plugin, method_name, None),
-                getattr(callback_plugin, 'v2_on_any', None)
-            ]
+
+            # try to find v2 method, fallback to v1 method, ignore callback if no method found
+            methods = []
+            for possible in [method_name, 'v2_on_any']:
+                gotit =  getattr(callback_plugin, possible, None)
+                if gotit is None:
+                    gotit = getattr(callback_plugin, possible.replace('v2_',''), None)
+                if gotit is not None:
+                    methods.append(gotit)
+
             for method in methods:
-                if method is not None:
                 try:
                     # temporary hack, required due to a change in the callback API, so
                     # we don't break backwards compatibility with callbacks which were
                     # designed to use the original API
-                        # FIXME: target for removal and revert to the original code here
-                        #        after a year (2017-01-14)
+                    # FIXME: target for removal and revert to the original code here after a year (2017-01-14)
                     if method_name == 'v2_playbook_on_start':
                         import inspect
                         (f_args, f_varargs, f_keywords, f_defaults) = inspect.getargspec(method)
@@ -306,13 +308,5 @@ class TaskQueueManager:
                     else:
                         method(*args, **kwargs)
                 except Exception as e:
-                        import traceback
-                        orig_tb = to_unicode(traceback.format_exc())
-                        try:
-                            v1_method = method.replace('v2_','')
-                            v1_method(*args, **kwargs)
-                        except Exception:
-                            if display.verbosity >= 3:
-                                display.warning(orig_tb, formatted=True)
-                            else:
-                                display.warning('Error when using %s: %s' % (method, str(e)))
+                    #TODO: add config toggle to make this fatal or not?
+                    display.warning(u"Failure when attempting to use callback plugin (%s): %s" % (to_unicode(callback_plugin), to_unicode(e)))