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