Source code for aio_pika.queue

import asyncio
from functools import partial
from types import TracebackType
from typing import Any, Callable, Optional, Type

import aiormq
from aiormq.abc import DeliveredMessage
from pamqp.common import Arguments

from .abc import (
    AbstractIncomingMessage, AbstractQueue, AbstractQueueIterator, ConsumerTag,
    TimeoutType, get_exchange_name,
)
from .exceptions import QueueEmpty
from .exchange import ExchangeParamType
from .log import get_logger
from .message import IncomingMessage
from .tools import CallbackCollection, create_task


log = get_logger(__name__)


async def consumer(
    callback: Callable[[AbstractIncomingMessage], Any],
    msg: DeliveredMessage, *,
    no_ack: bool,
) -> Any:
    message = IncomingMessage(msg, no_ack=no_ack)
    return await create_task(callback, message)


[docs]class Queue(AbstractQueue): """ AMQP queue abstraction """ def __init__( self, channel: aiormq.abc.AbstractChannel, name: Optional[str], durable: bool, exclusive: bool, auto_delete: bool, arguments: Arguments, passive: bool = False, ): self.__get_lock = asyncio.Lock() self.close_callbacks = CallbackCollection(self) self.channel = channel self.name = name or "" self.durable = durable self.exclusive = exclusive self.auto_delete = auto_delete self.arguments = arguments self.passive = passive def __str__(self) -> str: return f"{self.name}" def __repr__(self) -> str: return ( f"<{self.__class__.__name__}({self}): " f"auto_delete={self.auto_delete}, " f"durable={self.durable}, " f"exclusive={self.exclusive}, " f"arguments={self.arguments!r}" )
[docs] async def declare( self, timeout: TimeoutType = None, ) -> aiormq.spec.Queue.DeclareOk: """ Declare queue. :param timeout: execution timeout :param passive: Only check to see if the queue exists. :return: :class:`None` """ log.debug("Declaring queue: %r", self) self.declaration_result = await self.channel.queue_declare( queue=self.name, durable=self.durable, exclusive=self.exclusive, auto_delete=self.auto_delete, arguments=self.arguments, passive=self.passive, timeout=timeout, ) if self.declaration_result.queue is not None: self.name = self.declaration_result.queue else: self.name = "<UNNAMED>" return self.declaration_result
[docs] async def bind( self, exchange: ExchangeParamType, routing_key: Optional[str] = None, *, arguments: Arguments = None, timeout: TimeoutType = None, ) -> aiormq.spec.Queue.BindOk: """ A binding is a relationship between an exchange and a queue. This can be simply read as: the queue is interested in messages from this exchange. Bindings can take an extra routing_key parameter. To avoid the confusion with a basic_publish parameter we're going to call it a binding key. :param exchange: :class:`aio_pika.exchange.Exchange` instance :param routing_key: routing key :param arguments: additional arguments :param timeout: execution timeout :raises asyncio.TimeoutError: when the binding timeout period has elapsed. :return: :class:`None` """ if routing_key is None: routing_key = self.name log.debug( "Binding queue %r: exchange=%r, routing_key=%r, arguments=%r", self, exchange, routing_key, arguments, ) return await self.channel.queue_bind( self.name, exchange=get_exchange_name(exchange), routing_key=routing_key, arguments=arguments, timeout=timeout, )
[docs] async def unbind( self, exchange: ExchangeParamType, routing_key: Optional[str] = None, arguments: Arguments = None, timeout: TimeoutType = None, ) -> aiormq.spec.Queue.UnbindOk: """ Remove binding from exchange for this :class:`Queue` instance :param exchange: :class:`aio_pika.exchange.Exchange` instance :param routing_key: routing key :param arguments: additional arguments :param timeout: execution timeout :raises asyncio.TimeoutError: when the unbinding timeout period has elapsed. :return: :class:`None` """ if routing_key is None: routing_key = self.name log.debug( "Unbinding queue %r: exchange=%r, routing_key=%r, arguments=%r", self, exchange, routing_key, arguments, ) return await self.channel.queue_unbind( queue=self.name, exchange=get_exchange_name(exchange), routing_key=routing_key, arguments=arguments, timeout=timeout, )
[docs] async def consume( self, callback: Callable[[AbstractIncomingMessage], Any], no_ack: bool = False, exclusive: bool = False, arguments: Arguments = None, consumer_tag: Optional[ConsumerTag] = None, timeout: TimeoutType = None, ) -> ConsumerTag: """ Start to consuming the :class:`Queue`. :param timeout: :class:`asyncio.TimeoutError` will be raises when the Future was not finished after this time. :param callback: Consuming callback. Could be a coroutine. :param no_ack: if :class:`True` you don't need to call :func:`aio_pika.message.IncomingMessage.ack` :param exclusive: Makes this queue exclusive. Exclusive queues may only be accessed by the current connection, and are deleted when that connection closes. Passive declaration of an exclusive queue by other connections are not allowed. :param arguments: additional arguments :param consumer_tag: optional consumer tag :raises asyncio.TimeoutError: when the consuming timeout period has elapsed. :return str: consumer tag :class:`str` """ log.debug("Start to consuming queue: %r", self) consume_result = await self.channel.basic_consume( queue=self.name, consumer_callback=partial( consumer, callback, no_ack=no_ack, ), exclusive=exclusive, no_ack=no_ack, arguments=arguments, consumer_tag=consumer_tag, timeout=timeout, ) # consumer_tag property is Optional[str] in practice this check # should never take place, however, it protects against the case # if the `None` comes from pamqp if consume_result.consumer_tag is None: raise RuntimeError("Consumer tag is None") return consume_result.consumer_tag
[docs] async def cancel( self, consumer_tag: ConsumerTag, timeout: TimeoutType = None, nowait: bool = False, ) -> aiormq.spec.Basic.CancelOk: """ This method cancels a consumer. This does not affect already delivered messages, but it does mean the server will not send any more messages for that consumer. The client may receive an arbitrary number of messages in between sending the cancel method and receiving the cancel-ok reply. It may also be sent from the server to the client in the event of the consumer being unexpectedly cancelled (i.e. cancelled for any reason other than the server receiving the corresponding basic.cancel from the client). This allows clients to be notified of the loss of consumers due to events such as queue deletion. :param consumer_tag: consumer tag returned by :func:`~aio_pika.Queue.consume` :param timeout: execution timeout :param bool nowait: Do not expect a Basic.CancelOk response :return: Basic.CancelOk when operation completed successfully """ return await self.channel.basic_cancel( consumer_tag=consumer_tag, nowait=nowait, timeout=timeout, )
[docs] async def get( self, *, no_ack: bool = False, fail: bool = True, timeout: TimeoutType = 5, ) -> Optional[IncomingMessage]: """ Get message from the queue. :param no_ack: if :class:`True` you don't need to call :func:`aio_pika.message.IncomingMessage.ack` :param timeout: execution timeout :param fail: Should return :class:`None` instead of raise an exception :class:`aio_pika.exceptions.QueueEmpty`. :return: :class:`aio_pika.message.IncomingMessage` """ msg: DeliveredMessage = await self.channel.basic_get( self.name, no_ack=no_ack, timeout=timeout, ) if isinstance(msg.delivery, aiormq.spec.Basic.GetEmpty): if fail: raise QueueEmpty return None return IncomingMessage(msg, no_ack=no_ack)
[docs] async def purge( self, no_wait: bool = False, timeout: TimeoutType = None, ) -> aiormq.spec.Queue.PurgeOk: """ Purge all messages from the queue. :param no_wait: no wait response :param timeout: execution timeout :return: :class:`None` """ log.info("Purging queue: %r", self) return await self.channel.queue_purge( self.name, nowait=no_wait, timeout=timeout, )
[docs] async def delete( self, *, if_unused: bool = True, if_empty: bool = True, timeout: TimeoutType = None, ) -> aiormq.spec.Queue.DeleteOk: """ Delete the queue. :param if_unused: Perform delete only when unused :param if_empty: Perform delete only when empty :param timeout: execution timeout :return: :class:`None` """ log.info("Deleting %r", self) return await self.channel.queue_delete( self.name, if_unused=if_unused, if_empty=if_empty, timeout=timeout, )
def __aiter__(self) -> "AbstractQueueIterator": return self.iterator()
[docs] def iterator(self, **kwargs: Any) -> "AbstractQueueIterator": """ Returns an iterator for async for expression. Full example: .. code-block:: python import aio_pika async def main(): connection = await aio_pika.connect() async with connection: channel = await connection.channel() queue = await channel.declare_queue('test') async with queue.iterator() as q: async for message in q: print(message.body) When your program runs with run_forever the iterator will be closed in background. In this case the context processor for iterator might be skipped and the queue might be used in the "async for" expression directly. .. code-block:: python import aio_pika async def main(): connection = await aio_pika.connect() async with connection: channel = await connection.channel() queue = await channel.declare_queue('test') async for message in queue: print(message.body) :return: QueueIterator """ return QueueIterator(self, **kwargs)
class QueueIterator(AbstractQueueIterator): DEFAULT_CLOSE_TIMEOUT = 5 @property def consumer_tag(self) -> Optional[ConsumerTag]: return getattr(self, "_consumer_tag", None) async def close(self, *_: Any) -> Any: log.debug("Cancelling queue iterator %r", self) if not hasattr(self, "_consumer_tag"): log.debug("Queue iterator %r already cancelled", self) return if self._amqp_queue.channel.is_closed: log.debug("Queue iterator %r channel closed", self) return log.debug("Basic.cancel for %r", self.consumer_tag) consumer_tag = self._consumer_tag del self._consumer_tag self._amqp_queue.close_callbacks.remove(self.close) await self._amqp_queue.cancel(consumer_tag) log.debug("Queue iterator %r closed", self) # Reject all messages msg: Optional[IncomingMessage] = None try: while True: msg = self._queue.get_nowait() except asyncio.QueueEmpty: if msg is None: return if self._amqp_queue.channel.is_closed: log.warning( "Message %r lost when queue iterator %r channel closed", msg, self, ) return if self._consume_kwargs.get("no_ack", False): log.warning( "Message %r lost for consumer with no_ack %r", msg, self, ) return await msg.nack(requeue=True, multiple=True) def __str__(self) -> str: return f"queue[{self._amqp_queue}](...)" def __repr__(self) -> str: return ( f"<{self.__class__.__name__}: " f"queue={self._amqp_queue.name!r} " f"ctag={self.consumer_tag!r}>" ) def __init__(self, queue: Queue, **kwargs: Any): self._consumer_tag: ConsumerTag self._amqp_queue: AbstractQueue = queue self._queue = asyncio.Queue() self._consume_kwargs = kwargs self._amqp_queue.close_callbacks.add(self.close) async def on_message(self, message: AbstractIncomingMessage) -> None: await self._queue.put(message) async def consume(self) -> None: self._consumer_tag = await self._amqp_queue.consume( self.on_message, **self._consume_kwargs, ) def __aiter__(self) -> "AbstractQueueIterator": return self async def __aenter__(self) -> "AbstractQueueIterator": if not hasattr(self, "_consumer_tag"): await self.consume() return self async def __aexit__( self, exc_type: Optional[Type[BaseException]], exc_val: Optional[BaseException], exc_tb: Optional[TracebackType], ) -> None: await self.close() async def __anext__(self) -> IncomingMessage: if not hasattr(self, "_consumer_tag"): await self.consume() try: return await asyncio.wait_for( self._queue.get(), timeout=self._consume_kwargs.get("timeout"), ) except asyncio.CancelledError: timeout = self._consume_kwargs.get( "timeout", self.DEFAULT_CLOSE_TIMEOUT, ) log.info( "%r closing with timeout %d seconds", self, timeout, ) await asyncio.wait_for(self.close(), timeout=timeout) raise __all__ = ("Queue", "QueueIterator", "ConsumerTag")