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|
from typing import Optional, Union
import aiormq
from pamqp.common import Arguments
from .abc import (
AbstractChannel, AbstractExchange, AbstractMessage, ExchangeParamType,
ExchangeType, TimeoutType, get_exchange_name,
)
from .log import get_logger
log = get_logger(__name__)
class Exchange(AbstractExchange):
""" Exchange abstraction """
channel: AbstractChannel
def __init__(
self,
channel: AbstractChannel,
name: str,
type: Union[ExchangeType, str] = ExchangeType.DIRECT,
*,
auto_delete: bool = False,
durable: bool = False,
internal: bool = False,
passive: bool = False,
arguments: Arguments = None,
):
self._type = type.value if isinstance(type, ExchangeType) else type
self.channel = channel
self.name = name
self.auto_delete = auto_delete
self.durable = durable
self.internal = internal
self.passive = passive
self.arguments = arguments or {}
def __str__(self) -> str:
return self.name
def __repr__(self) -> str:
return (
f"<{self.__class__.__name__}({self}):"
f" auto_delete={self.auto_delete},"
f" durable={self.durable},"
f" arguments={self.arguments!r})>"
)
async def declare(
self, timeout: TimeoutType = None,
) -> aiormq.spec.Exchange.DeclareOk:
channel = await self.channel.get_underlay_channel()
return await channel.exchange_declare(
self.name,
exchange_type=self._type,
durable=self.durable,
auto_delete=self.auto_delete,
internal=self.internal,
passive=self.passive,
arguments=self.arguments,
timeout=timeout,
)
async def bind(
self,
exchange: ExchangeParamType,
routing_key: str = "",
*,
arguments: Arguments = None,
timeout: TimeoutType = None,
) -> aiormq.spec.Exchange.BindOk:
""" A binding can also be a relationship between two exchanges.
This can be simply read as: this exchange is interested in messages
from another 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.
.. code-block:: python
client = await connect()
routing_key = 'simple_routing_key'
src_exchange_name = "source_exchange"
dest_exchange_name = "destination_exchange"
channel = await client.channel()
src_exchange = await channel.declare_exchange(
src_exchange_name, auto_delete=True
)
dest_exchange = await channel.declare_exchange(
dest_exchange_name, auto_delete=True
)
queue = await channel.declare_queue(auto_delete=True)
await queue.bind(dest_exchange, routing_key)
await dest_exchange.bind(src_exchange, routing_key)
:param exchange: :class:`aio_pika.exchange.Exchange` instance
:param routing_key: routing key
:param arguments: additional arguments
:param timeout: execution timeout
:return: :class:`None`
"""
log.debug(
"Binding exchange %r to exchange %r, routing_key=%r, arguments=%r",
self,
exchange,
routing_key,
arguments,
)
channel = await self.channel.get_underlay_channel()
return await channel.exchange_bind(
arguments=arguments,
destination=self.name,
routing_key=routing_key,
source=get_exchange_name(exchange),
timeout=timeout,
)
async def unbind(
self,
exchange: ExchangeParamType,
routing_key: str = "",
arguments: Arguments = None,
timeout: TimeoutType = None,
) -> aiormq.spec.Exchange.UnbindOk:
""" Remove exchange-to-exchange binding for this
:class:`Exchange` instance
:param exchange: :class:`aio_pika.exchange.Exchange` instance
:param routing_key: routing key
:param arguments: additional arguments
:param timeout: execution timeout
:return: :class:`None`
"""
log.debug(
"Unbinding exchange %r from exchange %r, "
"routing_key=%r, arguments=%r",
self,
exchange,
routing_key,
arguments,
)
channel = await self.channel.get_underlay_channel()
return await channel.exchange_unbind(
arguments=arguments,
destination=self.name,
routing_key=routing_key,
source=get_exchange_name(exchange),
timeout=timeout,
)
async def publish(
self,
message: AbstractMessage,
routing_key: str,
*,
mandatory: bool = True,
immediate: bool = False,
timeout: TimeoutType = None,
) -> Optional[aiormq.abc.ConfirmationFrameType]:
""" Publish the message to the queue. `aio-pika` uses
`publisher confirms`_ extension for message delivery.
.. _publisher confirms: https://www.rabbitmq.com/confirms.html
"""
log.debug(
"Publishing message with routing key %r via exchange %r: %r",
routing_key,
self,
message,
)
if self.internal:
# Caught on the client side to prevent channel closure
raise ValueError(
f"Can not publish to internal exchange: '{self.name}'!",
)
if self.channel.is_closed:
raise aiormq.exceptions.ChannelInvalidStateError(
"%r closed" % self.channel,
)
channel = await self.channel.get_underlay_channel()
return await channel.basic_publish(
exchange=self.name,
routing_key=routing_key,
body=message.body,
properties=message.properties,
mandatory=mandatory,
immediate=immediate,
timeout=timeout,
)
async def delete(
self, if_unused: bool = False, timeout: TimeoutType = None,
) -> aiormq.spec.Exchange.DeleteOk:
""" Delete the queue
:param timeout: operation timeout
:param if_unused: perform deletion when queue has no bindings.
"""
log.info("Deleting %r", self)
channel = await self.channel.get_underlay_channel()
result = await channel.exchange_delete(
self.name, if_unused=if_unused, timeout=timeout,
)
del self.channel
return result
__all__ = ("Exchange", "ExchangeType", "ExchangeParamType")
|
