This document describes the current stable version of Kombu (5.0). For development docs, go here.
Source code for kombu.simple
"""Simple messaging interface."""
import socket
from collections import deque
from queue import Empty
from time import monotonic
from . import entity
from . import messaging
from .connection import maybe_channel
__all__ = ('SimpleQueue', 'SimpleBuffer')
class SimpleBase:
Empty = Empty
_consuming = False
def __enter__(self):
return self
def __exit__(self, *exc_info):
self.close()
def __init__(self, channel, producer, consumer, no_ack=False):
self.channel = maybe_channel(channel)
self.producer = producer
self.consumer = consumer
self.no_ack = no_ack
self.queue = self.consumer.queues[0]
self.buffer = deque()
self.consumer.register_callback(self._receive)
def get(self, block=True, timeout=None):
if not block:
return self.get_nowait()
self._consume()
time_start = monotonic()
remaining = timeout
while True:
if self.buffer:
return self.buffer.popleft()
if remaining is not None and remaining <= 0.0:
raise self.Empty()
try:
# The `drain_events` method will
# block on the socket connection to rabbitmq. if any
# application-level messages are received, it will put them
# into `self.buffer`.
# * The method will block for UP TO `timeout` milliseconds.
# * The method may raise a socket.timeout exception; or...
# * The method may return without having put anything on
# `self.buffer`. This is because internal heartbeat
# messages are sent over the same socket; also POSIX makes
# no guarantees against socket calls returning early.
self.channel.connection.client.drain_events(timeout=remaining)
except socket.timeout:
raise self.Empty()
if remaining is not None:
elapsed = monotonic() - time_start
remaining = timeout - elapsed
def get_nowait(self):
m = self.queue.get(no_ack=self.no_ack)
if not m:
raise self.Empty()
return m
def put(self, message, serializer=None, headers=None, compression=None,
routing_key=None, **kwargs):
self.producer.publish(message,
serializer=serializer,
routing_key=routing_key,
headers=headers,
compression=compression,
**kwargs)
def clear(self):
return self.consumer.purge()
def qsize(self):
_, size, _ = self.queue.queue_declare(passive=True)
return size
def close(self):
self.consumer.cancel()
def _receive(self, message_data, message):
self.buffer.append(message)
def _consume(self):
if not self._consuming:
self.consumer.consume(no_ack=self.no_ack)
self._consuming = True
def __len__(self):
"""`len(self) -> self.qsize()`."""
return self.qsize()
def __bool__(self):
return True
__nonzero__ = __bool__
[docs]class SimpleQueue(SimpleBase):
"""Simple API for persistent queues."""
no_ack = False
queue_opts = {}
queue_args = {}
exchange_opts = {'type': 'direct'}
def __init__(self, channel, name, no_ack=None, queue_opts=None,
queue_args=None, exchange_opts=None, serializer=None,
compression=None, **kwargs):
queue = name
queue_opts = dict(self.queue_opts, **queue_opts or {})
queue_args = dict(self.queue_args, **queue_args or {})
exchange_opts = dict(self.exchange_opts, **exchange_opts or {})
if no_ack is None:
no_ack = self.no_ack
if not isinstance(queue, entity.Queue):
exchange = entity.Exchange(name, **exchange_opts)
queue = entity.Queue(name, exchange, name,
queue_arguments=queue_args,
**queue_opts)
routing_key = name
else:
exchange = queue.exchange
routing_key = queue.routing_key
consumer = messaging.Consumer(channel, queue)
producer = messaging.Producer(channel, exchange,
serializer=serializer,
routing_key=routing_key,
compression=compression)
super().__init__(channel, producer,
consumer, no_ack, **kwargs)
[docs]class SimpleBuffer(SimpleQueue):
"""Simple API for ephemeral queues."""
no_ack = True
queue_opts = {'durable': False,
'auto_delete': True}
exchange_opts = {'durable': False,
'delivery_mode': 'transient',
'auto_delete': True}