117 lines
3.3 KiB
Python
117 lines
3.3 KiB
Python
"""
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kombu.abstract
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==============
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Object utilities.
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"""
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from __future__ import absolute_import
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from copy import copy
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from .connection import maybe_channel
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from .exceptions import NotBoundError
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from .utils import ChannelPromise
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__all__ = ['Object', 'MaybeChannelBound']
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def unpickle_dict(cls, kwargs):
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return cls(**kwargs)
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class Object(object):
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"""Common base class supporting automatic kwargs->attributes handling,
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and cloning."""
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attrs = ()
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def __init__(self, *args, **kwargs):
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any = lambda v: v
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for name, type_ in self.attrs:
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value = kwargs.get(name)
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if value is not None:
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setattr(self, name, (type_ or any)(value))
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else:
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try:
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getattr(self, name)
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except AttributeError:
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setattr(self, name, None)
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def as_dict(self, recurse=False):
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def f(obj, type):
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if recurse and isinstance(obj, Object):
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return obj.as_dict(recurse=True)
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return type(obj) if type else obj
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return dict(
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(attr, f(getattr(self, attr), type)) for attr, type in self.attrs
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)
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def __reduce__(self):
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return unpickle_dict, (self.__class__, self.as_dict())
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def __copy__(self):
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return self.__class__(**self.as_dict())
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class MaybeChannelBound(Object):
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"""Mixin for classes that can be bound to an AMQP channel."""
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_channel = None
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_is_bound = False
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#: Defines whether maybe_declare can skip declaring this entity twice.
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can_cache_declaration = False
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def __call__(self, channel):
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"""`self(channel) -> self.bind(channel)`"""
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return self.bind(channel)
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def bind(self, channel):
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"""Create copy of the instance that is bound to a channel."""
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return copy(self).maybe_bind(channel)
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def maybe_bind(self, channel):
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"""Bind instance to channel if not already bound."""
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if not self.is_bound and channel:
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self._channel = maybe_channel(channel)
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self.when_bound()
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self._is_bound = True
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return self
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def revive(self, channel):
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"""Revive channel after the connection has been re-established.
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Used by :meth:`~kombu.Connection.ensure`.
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"""
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if self.is_bound:
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self._channel = channel
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self.when_bound()
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def when_bound(self):
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"""Callback called when the class is bound."""
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pass
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def __repr__(self, item=''):
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item = item or type(self).__name__
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if self.is_bound:
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return '<{0} bound to chan:{1}>'.format(
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item or type(self).__name__, self.channel.channel_id)
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return '<unbound {0}>'.format(item)
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@property
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def is_bound(self):
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"""Flag set if the channel is bound."""
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return self._is_bound and self._channel is not None
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@property
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def channel(self):
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"""Current channel if the object is bound."""
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channel = self._channel
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if channel is None:
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raise NotBoundError(
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"Can't call method on {0} not bound to a channel".format(
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type(self).__name__))
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if isinstance(channel, ChannelPromise):
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channel = self._channel = channel()
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return channel
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