def __init__(self,
connection=None,
exchange=None,
queue=None,
default_timeout = 3000, # milliseconds
):
for param in ('exchange', 'queue'):
if not getparam(self, param, None):
raise ParameterMissing("%s is a required parameter" % param)
if connection:
self.connection = connection
else:
self.connection = mb_connection # defined in the messaging.messagebus module
self.amqp_channel = self.connection.channel()
self.amqp_channel.exchange_declare(exchange, 'direct')
self.amqp_channel.queue_declare(queue, auto_delete=True)
self.incoming_messages = Queue()
self.consumption_thread = ConsumptionThread(connection=self.connection)
self.consumption_thread.set_callback(queue=self.queue, callback=self.incoming_message_callback, no_ack=True)
self.consumption_thread.start()
class AmqpRpcEndpoint(object):
class ParameterMissing(Exception):
pass
def __init__(self,
connection=None,
exchange=None,
queue=None,
default_timeout = 3000, # milliseconds
):
for param in ('exchange', 'queue'):
if not getparam(self, param, None):
raise ParameterMissing("%s is a required parameter" % param)
if connection:
self.connection = connection
else:
self.connection = mb_connection # defined in the messaging.messagebus module
self.amqp_channel = self.connection.channel()
self.amqp_channel.exchange_declare(exchange, 'direct')
self.amqp_channel.queue_declare(queue, auto_delete=True)
self.incoming_messages = Queue()
self.consumption_thread = ConsumptionThread(connection=self.connection)
self.consumption_thread.set_callback(queue=self.queue, callback=self.incoming_message_callback, no_ack=True)
self.consumption_thread.start()
def serialize_message(self, pb_message):
''' Serializes a protobuf message into an array of bytes, ready for transport '''
bytes = pb_message.SerializeToString()
return bytes
def parse_message(self, messageclass, bytes):
''' Parse an array of bytes into a protobuf message. '''
message = messageclass()
message.ParseFromString(bytes)
return message
def send_message(self, message, routing_key):
''' Serialize and send a protobuf message along a specified AMQP route '''
self.messagebus.publish(self.serialize_message(message), exchange=self.exchange, routing_key=routing_key)
def get_message(self,messageclass, timeout=-2):
'''
Read and deserialize a protobuf message from the wire.
For timeout, -2 means "use default", -1 means "none", and anything
else means "timeout" milliseconds
'''
bytes = self.get_bytes(timeout=timeout)
self.parse_message(messageclass, bytes)
return message
def send_bytes(self, bytes, routing_key):
''' Send an array of bytes along a specified AMQP route '''
self.amqp_channel.basic_publish(bytes, exchange=self.exchange, routing_key=routing_key)
def incoming_message_callback(self, msg):
self.incoming_messages.put(msg)
def get_bytes(self, timeout = -2):
'''
Get an array of bytes from the incoming queue.
For timeout, -2 means "use default", -1 means "none", and anything
else means "timeout" milliseconds
'''
if timeout == -1:
return self.incoming_messages.get()
if timeout == -2:
timeout = self.default_timeout
return self.incoming_messages.get(True, timeout / 1000)
def bind_service(self, pb_service, routing_key):
''' Bind an rpc service to a specified routing key '''
self.service = pb_service
self.routing_key = routing_key
self.amqp_channel.queue_bind(self.queue, self.exchange, routing_key=self.routing_key)
def unbind_service(self):
raise NotImplementedError
def incoming_message_queue_size(self):
''' NOTE: qsize() is approximate. '''
return self.incoming_messages.qsize()
def Reset(self):
raise NotImplementedError
# Attribute setters are not so useful in python.
# def set_default_timeout(self, timeout = -1):
# ''' Change the default global timeout. -1 means "no timeout" '''
# self.default_timeout = timeout
def Failed(self):
raise NotImplementedError
