164 lines
4.8 KiB
Python
164 lines
4.8 KiB
Python
"""Code common to Connection and Channel objects."""
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# Copyright (C) 2007-2008 Barry Pederson <bp@barryp.org>)
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import logging
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from vine import ensure_promise, promise
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from .exceptions import AMQPNotImplementedError, RecoverableConnectionError
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from .serialization import dumps, loads
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__all__ = ('AbstractChannel',)
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AMQP_LOGGER = logging.getLogger('amqp')
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IGNORED_METHOD_DURING_CHANNEL_CLOSE = """\
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Received method %s during closing channel %s. This method will be ignored\
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"""
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class AbstractChannel:
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"""Superclass for Connection and Channel.
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The connection is treated as channel 0, then comes
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user-created channel objects.
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The subclasses must have a _METHOD_MAP class property, mapping
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between AMQP method signatures and Python methods.
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"""
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def __init__(self, connection, channel_id):
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self.is_closing = False
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self.connection = connection
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self.channel_id = channel_id
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connection.channels[channel_id] = self
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self.method_queue = [] # Higher level queue for methods
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self.auto_decode = False
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self._pending = {}
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self._callbacks = {}
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self._setup_listeners()
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__slots__ = (
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"is_closing",
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"connection",
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"channel_id",
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"method_queue",
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"auto_decode",
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"_pending",
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"_callbacks",
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# adding '__dict__' to get dynamic assignment
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"__dict__",
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"__weakref__",
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)
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def __enter__(self):
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return self
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def __exit__(self, *exc_info):
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self.close()
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def send_method(self, sig,
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format=None, args=None, content=None,
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wait=None, callback=None, returns_tuple=False):
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p = promise()
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conn = self.connection
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if conn is None:
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raise RecoverableConnectionError('connection already closed')
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args = dumps(format, args) if format else ''
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try:
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conn.frame_writer(1, self.channel_id, sig, args, content)
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except StopIteration:
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raise RecoverableConnectionError('connection already closed')
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# TODO temp: callback should be after write_method ... ;)
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if callback:
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p.then(callback)
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p()
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if wait:
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return self.wait(wait, returns_tuple=returns_tuple)
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return p
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def close(self):
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"""Close this Channel or Connection."""
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raise NotImplementedError('Must be overridden in subclass')
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def wait(self, method, callback=None, timeout=None, returns_tuple=False):
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p = ensure_promise(callback)
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pending = self._pending
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prev_p = []
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if not isinstance(method, list):
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method = [method]
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for m in method:
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prev_p.append(pending.get(m))
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pending[m] = p
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try:
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while not p.ready:
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self.connection.drain_events(timeout=timeout)
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if p.value:
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args, kwargs = p.value
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args = args[1:] # We are not returning method back
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return args if returns_tuple else (args and args[0])
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finally:
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for i, m in enumerate(method):
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if prev_p[i] is not None:
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pending[m] = prev_p[i]
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else:
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pending.pop(m, None)
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def dispatch_method(self, method_sig, payload, content):
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if self.is_closing and method_sig not in (
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self._ALLOWED_METHODS_WHEN_CLOSING
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):
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# When channel.close() was called we must ignore all methods except
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# Channel.close and Channel.CloseOk
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AMQP_LOGGER.warning(
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IGNORED_METHOD_DURING_CHANNEL_CLOSE,
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method_sig, self.channel_id
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)
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return
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if content and \
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self.auto_decode and \
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hasattr(content, 'content_encoding'):
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try:
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content.body = content.body.decode(content.content_encoding)
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except Exception:
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pass
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try:
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amqp_method = self._METHODS[method_sig]
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except KeyError:
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raise AMQPNotImplementedError(
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f'Unknown AMQP method {method_sig!r}')
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try:
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listeners = [self._callbacks[method_sig]]
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except KeyError:
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listeners = []
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one_shot = None
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try:
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one_shot = self._pending.pop(method_sig)
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except KeyError:
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if not listeners:
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return
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args = []
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if amqp_method.args:
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args, _ = loads(amqp_method.args, payload, 4)
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if amqp_method.content:
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args.append(content)
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for listener in listeners:
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listener(*args)
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if one_shot:
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one_shot(method_sig, *args)
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#: Placeholder, the concrete implementations will have to
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#: supply their own versions of _METHOD_MAP
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_METHODS = {}
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