class AMQPService(object):
"""
Class to serve all available queues and commands to the AMQP broker. It
makes use of a couple of configuration flags provided by the gosa
configurations file ``[amqp]`` section:
============== =============
Key Description
============== =============
url AMQP URL to connect to the broker
id User name to connect with
key Password to connect with
command-worker Number of worker processes
============== =============
Example::
[amqp]
url = amqps://amqp.intranet.gonicus.de:5671
id = node1
key = secret
"""
implements(IInterfaceHandler)
_priority_ = 1
def __init__(self):
env = Environment.getInstance()
self.log = logging.getLogger(__name__)
self.log.info("initializing AMQP service provider")
self.env = env
self.__cr = None
self.__zeroconf = None
self.__cmdWorker = None
def serve(self):
""" Start AMQP service for this GOsa service provider. """
# Load AMQP and Command registry instances
amqp = PluginRegistry.getInstance('AMQPHandler')
self.__cr = PluginRegistry.getInstance('CommandRegistry')
# Create a list of queues we need here
queues = {}
for dsc in self.__cr.commands.values():
queues[dsc['target']] = True
# Finally create the queues
for queue in queues:
# Add round robin processor for queue
self.__cmdWorker = AMQPWorker(self.env, connection=amqp.getConnection(),
r_address='%s.command.%s; { create:always, node:{ type:queue, x-bindings:[ { exchange:"amq.direct", queue:"%s.command.%s" } ] } }' % (self.env.domain, queue, self.env.domain, queue),
workers=self.env.config.get('amqp.command-worker', default=1),
callback=self.commandReceived)
# Add private processor for queue
self.__cmdWorker = AMQPWorker(self.env, connection=amqp.getConnection(),
r_address='%s.command.%s.%s; { create:always, delete:receiver, node:{ type:queue, x-bindings:[ { exchange:"amq.direct", queue:"%s.command.%s.%s" } ] } }' % (self.env.domain, queue, self.env.id, self.env.domain, queue, self.env.id),
workers=self.env.config.get('amqp.command-worker', default=1),
callback=self.commandReceived)
# Announce service
url = parseURL(self.env.config.get("amqp.url"))
self.__zeroconf = ZeroconfService(name="GOsa AMQP command service",
port=url['port'],
stype="_%s._tcp" % url['scheme'],
text="path=%s\001service=gosa" % url['path'])
self.__zeroconf.publish()
self.log.info("ready to process incoming requests")
def stop(self):
""" Stop AMQP service for this GOsa service provider. """
self.__zeroconf.unpublish()
def commandReceived(self, ssn, message):
"""
Process incoming commands, coming in with session and message
information.
================= ==========================
Parameter Description
================= ==========================
ssn AMQP session object
message Received AMQP message
================= ==========================
Incoming messages are coming from an
:class:`gosa.common.components.amqp_proxy.AMQPServiceProxy` which
is providing a *reply to* queue as a return channel. The command
result is written to that queue.
"""
# Check for id
if not message.user_id:
raise ValueError("incoming message without user_id")
err = None
res = None
id_ = ''
try:
req = loads(message.content)
except ServiceRequestNotTranslatable, e:
err = str(e)
req = {'id': id_}
if err == None:
try:
id_ = req['id']
name = req['method']
args = req['params']
except KeyError:
err = str(BadServiceRequest(message.content))
if not isinstance(args, list) and not isinstance(args, dict):
raise ValueError("bad params %r: must be a list or dict" % args)
# Extract source queue
p = re.compile(r';.*$')
queue = p.sub('', message._receiver.source)
self.log.info("received call [%s/%s] for %s: %s(%s)" % (id_, queue, message.user_id, name, args))
# Don't process messages if the command registry thinks it's not ready
if not self.__cr.processing.is_set():
self.log.warning("waiting for registry to get ready")
if not self.__cr.processing.wait(5):
self.log.error("releasing call [%s/%s] for %s: %s(%s) - timed out" % (id_, queue, message.user_id, name, args))
ssn.acknowledge(message, Disposition(RELEASED, set_redelivered=True))
return
# Try to execute either with or without keyword arguments
if err == None:
try:
if isinstance(args, dict):
res = self.__cr.dispatch(message.user_id, queue, name, **args)
else:
res = self.__cr.dispatch(message.user_id, queue, name, *args)
# Catch everything that might happen in the dispatch, pylint: disable=W0703
except Exception as e:
text = traceback.format_exc()
self.log.exception(text)
err = str(e)
exc_value = sys.exc_info()[1]
# If message starts with [, it's a translateable message in
# repr format
if err.startswith("[") or err.startswith("("):
if err.startswith("("):
err = "[" + err[1:-1] + "]"
err = loads(repr2json(err))
err = dict(
name='JSONRPCError',
code=100,
message=str(exc_value),
error=err)
self.log.debug("returning call [%s]: %s / %s" % (id_, res, err))
response = dumps({"result": res, "id": id_, "error": err})
ssn.acknowledge(message)
# Talk to client generated reply queue
sender = ssn.sender(message.reply_to)
# Get rid of it...
sender.send(Message(response))
