@ -16,7 +16,8 @@
import itertools
import logging
import sys
import six
from oslo_messaging import dispatcher
from oslo_messaging import localcontext
@ -33,17 +34,7 @@ class NotificationResult(object):
REQUEUE = ' requeue '
class NotificationDispatcher ( dispatcher . DispatcherBase ) :
""" A message dispatcher which understands Notification messages.
A MessageHandlingServer is constructed by passing a callable dispatcher
which is invoked with context and message dictionaries each time a message
is received .
NotifcationDispatcher is one such dispatcher which pass a raw notification
message to the endpoints
"""
class _NotificationDispatcherBase ( dispatcher . DispatcherBase ) :
def __init__ ( self , targets , endpoints , serializer , allow_requeue ,
pool = None ) :
self . targets = targets
@ -74,12 +65,15 @@ class NotificationDispatcher(dispatcher.DispatcherBase):
executor_callback = executor_callback ,
post = self . _post_dispatch )
@staticmethod
def _post_dispatch ( incoming , result ) :
if result == NotificationResult . HANDLED :
incoming . acknowledge ( )
else :
incoming . requeue ( )
def _post_dispatch ( self , incoming , requeues ) :
for m in incoming :
try :
if requeues and m in requeues :
m . requeue ( )
else :
m . acknowledge ( )
except Exception :
LOG . error ( " Fail to ack/requeue message " , exc_info = True )
def _dispatch_and_handle_error ( self , incoming , executor_callback ) :
""" Dispatch a notification message to the appropriate endpoint method.
@ -88,24 +82,59 @@ class NotificationDispatcher(dispatcher.DispatcherBase):
: type ctxt : IncomingMessage
"""
try :
return self . _dispatch ( incoming . ctxt , incoming . message ,
executor_callback )
return self . _dispatch ( incoming , executor_callback )
except Exception :
# sys.exc_info() is deleted by LOG.exception().
exc_info = sys . exc_info ( )
LOG . error ( ' Exception during message handling ' ,
exc_info = exc_info )
return NotificationResult . HANDLED
def _dispatch ( self , ctxt , message , executor_callback = None ) :
""" Dispatch an RPC message to the appropriate endpoint method.
: param ctxt : the request context
: type ctxt : dict
: param message : the message payload
: type message : dict
LOG . error ( ' Exception during message handling ' , exc_info = True )
def _dispatch ( self , incoming , executor_callback = None ) :
""" Dispatch notification messages to the appropriate endpoint method.
"""
ctxt = self . serializer . deserialize_context ( ctxt )
messages_grouped = itertools . groupby ( (
self . _extract_user_message ( m )
for m in incoming ) , lambda x : x [ 0 ] )
requeues = set ( )
for priority , messages in messages_grouped :
__ , raw_messages , messages = six . moves . zip ( * messages )
raw_messages = list ( raw_messages )
messages = list ( messages )
if priority not in PRIORITIES :
LOG . warning ( ' Unknown priority " %s " ' , priority )
continue
for screen , callback in self . _callbacks_by_priority . get ( priority ,
[ ] ) :
if screen :
filtered_messages = [ message for message in messages
if screen . match (
message [ " ctxt " ] ,
message [ " publisher_id " ] ,
message [ " event_type " ] ,
message [ " metadata " ] ,
message [ " payload " ] ) ]
else :
filtered_messages = messages
if not filtered_messages :
continue
ret = self . _exec_callback ( executor_callback , callback ,
filtered_messages )
if self . allow_requeue and ret == NotificationResult . REQUEUE :
requeues . update ( raw_messages )
break
return requeues
def _exec_callback ( self , executor_callback , callback , * args ) :
if executor_callback :
ret = executor_callback ( callback , * args )
else :
ret = callback ( * args )
return NotificationResult . HANDLED if ret is None else ret
def _extract_user_message ( self , incoming ) :
ctxt = self . serializer . deserialize_context ( incoming . ctxt )
message = incoming . message
publisher_id = message . get ( ' publisher_id ' )
event_type = message . get ( ' event_type ' )
@ -114,28 +143,50 @@ class NotificationDispatcher(dispatcher.DispatcherBase):
' timestamp ' : message . get ( ' timestamp ' )
}
priority = message . get ( ' priority ' , ' ' ) . lower ( )
if priority not in PRIORITIES :
LOG . warning ( ' Unknown priority " %s " ' , priority )
return
payload = self . serializer . deserialize_entity ( ctxt ,
message . get ( ' payload ' ) )
return priority , incoming , dict ( ctxt = ctxt ,
publisher_id = publisher_id ,
event_type = event_type ,
payload = payload ,
metadata = metadata )
for screen , callback in self . _callbacks_by_priority . get ( priority , [ ] ) :
if screen and not screen . match ( ctxt , publisher_id , event_type ,
metadata , payload ) :
continue
localcontext . _set_local_context ( ctxt )
try :
if executor_callback :
ret = executor_callback ( callback , ctxt , publisher_id ,
event_type , payload , metadata )
else :
ret = callback ( ctxt , publisher_id , event_type , payload ,
metadata )
ret = NotificationResult . HANDLED if ret is None else ret
if self . allow_requeue and ret == NotificationResult . REQUEUE :
return ret
finally :
localcontext . _clear_local_context ( )
return NotificationResult . HANDLED
class NotificationDispatcher ( _NotificationDispatcherBase ) :
""" A message dispatcher which understands Notification messages.
A MessageHandlingServer is constructed by passing a callable dispatcher
which is invoked with context and message dictionaries each time a message
is received .
"""
def _exec_callback ( self , executor_callback , callback , messages ) :
localcontext . _set_local_context (
messages [ 0 ] [ " ctxt " ] )
try :
return super ( NotificationDispatcher , self ) . _exec_callback (
executor_callback , callback ,
messages [ 0 ] [ " ctxt " ] ,
messages [ 0 ] [ " publisher_id " ] ,
messages [ 0 ] [ " event_type " ] ,
messages [ 0 ] [ " payload " ] ,
messages [ 0 ] [ " metadata " ] )
finally :
localcontext . _clear_local_context ( )
class BatchNotificationDispatcher ( _NotificationDispatcherBase ) :
""" A message dispatcher which understands Notification messages.
A MessageHandlingServer is constructed by passing a callable dispatcher
which is invoked with a list of message dictionaries each time ' batch_size '
messages are received or ' batch_timeout ' seconds is reached .
"""
def __init__ ( self , targets , endpoints , serializer , allow_requeue ,
pool = None , batch_size = None , batch_timeout = None ) :
super ( BatchNotificationDispatcher , self ) . __init__ ( targets , endpoints ,
serializer ,
allow_requeue ,
pool )
self . batch_size = batch_size
self . batch_timeout = batch_timeout
Mehdi Abaakouk
8 years ago