144 lines
4.3 KiB
Python
144 lines
4.3 KiB
Python
"""Object utilities."""
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from __future__ import annotations
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from copy import copy
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from typing import TYPE_CHECKING, Any, Callable, TypeVar
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from .connection import maybe_channel
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from .exceptions import NotBoundError
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from .utils.functional import ChannelPromise
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if TYPE_CHECKING:
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from kombu.connection import Connection
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from kombu.transport.virtual import Channel
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__all__ = ('Object', 'MaybeChannelBound')
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_T = TypeVar("_T")
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_ObjectType = TypeVar("_ObjectType", bound="Object")
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_MaybeChannelBoundType = TypeVar(
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"_MaybeChannelBoundType", bound="MaybeChannelBound"
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)
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def unpickle_dict(
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cls: type[_ObjectType], kwargs: dict[str, Any]
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) -> _ObjectType:
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return cls(**kwargs)
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def _any(v: _T) -> _T:
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return v
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class Object:
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"""Common base class.
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Supports automatic kwargs->attributes handling, and cloning.
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"""
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attrs: tuple[tuple[str, Any], ...] = ()
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def __init__(self, *args: Any, **kwargs: Any) -> None:
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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: bool = False) -> dict[str, Any]:
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def f(obj: Any, type: Callable[[Any], Any] | None = None) -> Any:
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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 and obj is not None else obj
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return {
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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: _ObjectType) -> tuple[
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Callable[[type[_ObjectType], dict[str, Any]], _ObjectType],
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tuple[type[_ObjectType], dict[str, Any]]
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]:
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return unpickle_dict, (self.__class__, self.as_dict())
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def __copy__(self: _ObjectType) -> _ObjectType:
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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: Channel | None = 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__(
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self: _MaybeChannelBoundType, channel: (Channel | Connection)
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) -> _MaybeChannelBoundType:
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"""`self(channel) -> self.bind(channel)`."""
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return self.bind(channel)
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def bind(
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self: _MaybeChannelBoundType, channel: (Channel | Connection)
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) -> _MaybeChannelBoundType:
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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(
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self: _MaybeChannelBoundType, channel: (Channel | Connection)
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) -> _MaybeChannelBoundType:
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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: Channel) -> None:
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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) -> None:
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"""Callback called when the class is bound."""
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def __repr__(self) -> str:
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return self._repr_entity(type(self).__name__)
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def _repr_entity(self, item: str = '') -> str:
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item = item or type(self).__name__
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if self.is_bound:
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return '<{} bound to chan:{}>'.format(
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item or type(self).__name__, self.channel.channel_id)
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return f'<unbound {item}>'
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@property
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def is_bound(self) -> bool:
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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) -> Channel:
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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 {} 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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