Fix duplicate callback issue in v2

All v2+ callbacks can now optionally define a CALLBACK_TYPE, which
when set to 'stdout' will limit those callbacks which are used for
primary output to a single callback plugin (specified to the
TaskQueueManager object and configurable in ansible.cfg/environment)

v2/ansible/constants.py

@@ -162,6 +162,7 @@ DEFAULT_CONNECTION_PLUGIN_PATH = get_config(p, DEFAULTS, 'connection_plugins', '
 DEFAULT_LOOKUP_PLUGIN_PATH     = get_config(p, DEFAULTS, 'lookup_plugins',     'ANSIBLE_LOOKUP_PLUGINS', '~/.ansible/plugins/lookup_plugins:/usr/share/ansible_plugins/lookup_plugins')
 DEFAULT_VARS_PLUGIN_PATH       = get_config(p, DEFAULTS, 'vars_plugins',       'ANSIBLE_VARS_PLUGINS', '~/.ansible/plugins/vars_plugins:/usr/share/ansible_plugins/vars_plugins')
 DEFAULT_FILTER_PLUGIN_PATH     = get_config(p, DEFAULTS, 'filter_plugins',     'ANSIBLE_FILTER_PLUGINS', '~/.ansible/plugins/filter_plugins:/usr/share/ansible_plugins/filter_plugins')
+DEFAULT_STDOUT_CALLBACK        = get_config(p, DEFAULTS, 'stdout_callback',    'ANSIBLE_STDOUT_CALLBACK', 'default')
 
 CACHE_PLUGIN                   = get_config(p, DEFAULTS, 'fact_caching', 'ANSIBLE_CACHE_PLUGIN', 'memory')
 CACHE_PLUGIN_CONNECTION        = get_config(p, DEFAULTS, 'fact_caching_connection', 'ANSIBLE_CACHE_PLUGIN_CONNECTION', None)

v2/ansible/executor/playbook_executor.py

@@ -48,7 +48,7 @@ class PlaybookExecutor:
         if options.listhosts or options.listtasks or options.listtags:
             self._tqm = None
         else:
-            self._tqm = TaskQueueManager(inventory=inventory, callback='default', variable_manager=variable_manager, loader=loader, display=display, options=options, passwords=self.passwords)
+            self._tqm = TaskQueueManager(inventory=inventory, variable_manager=variable_manager, loader=loader, display=display, options=options, passwords=self.passwords)
 
     def run(self):
 

v2/ansible/executor/task_queue_manager.py

@@ -24,6 +24,7 @@ import os
 import socket
 import sys
 
+from ansible import constants as C
 from ansible.errors import AnsibleError
 from ansible.executor.connection_info import ConnectionInformation
 from ansible.executor.play_iterator import PlayIterator
@@ -48,7 +49,7 @@ class TaskQueueManager:
     which dispatches the Play's tasks to hosts.
     '''
 
-    def __init__(self, inventory, callback, variable_manager, loader, display, options, passwords):
+    def __init__(self, inventory, variable_manager, loader, display, options, passwords, stdout_callback=None):
 
         self._inventory        = inventory
         self._variable_manager = variable_manager
@@ -70,14 +71,8 @@ class TaskQueueManager:
 
         self._final_q = multiprocessing.Queue()
 
-        # load all available callback plugins
-        # FIXME: we need an option to white-list callback plugins
-        self._callback_plugins = []
-        for callback_plugin in callback_loader.all(class_only=True):
-            if hasattr(callback_plugin, 'CALLBACK_VERSION') and callback_plugin.CALLBACK_VERSION >= 2.0:
-                self._callback_plugins.append(callback_plugin(self._display))
-            else:
-                self._callback_plugins.append(callback_plugin())
+        # load callback plugins
+        self._callback_plugins = self._load_callbacks(stdout_callback)
 
         # create the pool of worker threads, based on the number of forks specified
         try:
@@ -120,6 +115,40 @@ class TaskQueueManager:
         for handler in handler_list:
             self._notified_handlers[handler.get_name()] = []
 
+    def _load_callbacks(self, stdout_callback):
+        '''
+        Loads all available callbacks, with the exception of those which
+        utilize the CALLBACK_TYPE option. When CALLBACK_TYPE is set to 'stdout',
+        only one such callback plugin will be loaded.
+        '''
+
+        loaded_plugins = []
+
+        stdout_callback_loaded = False
+        if stdout_callback is None:
+            stdout_callback = C.DEFAULT_STDOUT_CALLBACK
+
+        if stdout_callback not in callback_loader:
+            raise AnsibleError("Invalid callback for stdout specified: %s" % stdout_callback)
+
+        for callback_plugin in callback_loader.all(class_only=True):
+            if hasattr(callback_plugin, 'CALLBACK_VERSION') and callback_plugin.CALLBACK_VERSION >= 2.0:
+                # we only allow one callback of type 'stdout' to be loaded, so check
+                # the name of the current plugin and type to see if we need to skip
+                # loading this callback plugin
+                callback_type = getattr(callback_plugin, 'CALLBACK_TYPE', None)
+                (callback_name, _) = os.path.splitext(os.path.basename(callback_plugin._original_path))
+                if callback_type == 'stdout':
+                    if callback_name != stdout_callback or stdout_callback_loaded:
+                        continue
+                    stdout_callback_loaded = True
+
+                loaded_plugins.append(callback_plugin(self._display))
+            else:
+                loaded_plugins.append(callback_plugin())
+
+        return loaded_plugins
+
     def run(self, play):
         '''
         Iterates over the roles/tasks in a play, using the given (or default)

v2/ansible/plugins/__init__.py

@@ -243,9 +243,12 @@ class PluginLoader:
                 if path not in self._module_cache:
                     self._module_cache[path] = imp.load_source('.'.join([self.package, name]), path)
                 if kwargs.get('class_only', False):
-                    yield getattr(self._module_cache[path], self.class_name)
+                    obj = getattr(self._module_cache[path], self.class_name)
                 else:
-                    yield getattr(self._module_cache[path], self.class_name)(*args, **kwargs)
+                    obj = getattr(self._module_cache[path], self.class_name)(*args, **kwargs)
+                # set extra info on the module, in case we want it later
+                setattr(obj, '_original_path', path)
+                yield obj
 
 action_loader = PluginLoader(
     'ActionModule',

v2/ansible/plugins/callback/default.py

@@ -31,6 +31,7 @@ class CallbackModule(CallbackBase):
     '''
 
     CALLBACK_VERSION = 2.0
+    CALLBACK_TYPE = 'stdout'
 
     def v2_on_any(self, *args, **kwargs):
         pass

v2/ansible/plugins/callback/minimal.py

@@ -32,6 +32,7 @@ class CallbackModule(CallbackBase):
     '''
 
     CALLBACK_VERSION = 2.0
+    CALLBACK_TYPE = 'stdout'
 
     def v2_on_any(self, *args, **kwargs):
         pass

v2/bin/ansible

@@ -150,7 +150,7 @@ class Cli(object):
         # now create a task queue manager to execute the play
         try:
             display = Display()
-            tqm = TaskQueueManager(inventory=inventory, callback='minimal', variable_manager=variable_manager, loader=loader, display=display, options=options, passwords=passwords)
+            tqm = TaskQueueManager(inventory=inventory, variable_manager=variable_manager, loader=loader, display=display, options=options, passwords=passwords, stdout_callback='minimal')
             result = tqm.run(play)
             tqm.cleanup()
         except AnsibleError: