Source code for dramatiq.middleware.current_message

# This file is a part of Dramatiq.
#
# Copyright (C) 2019 CLEARTYPE SRL <[email protected]>
#
# Dramatiq is free software; you can redistribute it and/or modify it
# under the terms of the GNU Lesser General Public License as published by
# the Free Software Foundation, either version 3 of the License, or (at
# your option) any later version.
#
# Dramatiq is distributed in the hope that it will be useful, but WITHOUT
# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
# FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
# License for more details.
#
# You should have received a copy of the GNU Lesser General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.

import contextvars
from typing import TYPE_CHECKING, Any, Optional

from .middleware import Middleware

if TYPE_CHECKING:
    from ..message import Message


[docs] class CurrentMessage(Middleware): """Middleware that exposes the current message via a thread-local variable. Example: >>> import dramatiq >>> from dramatiq.middleware import CurrentMessage >>> @dramatiq.actor ... def example(x): ... print(CurrentMessage.get_current_message()) ... >>> example.send(1) """ _MESSAGE: contextvars.ContextVar[ "Optional[Message[Any]]" ] = contextvars.ContextVar("_MESSAGE", default=None)
[docs] @classmethod def get_current_message(cls) -> "Optional[Message[Any]]": """Get the message that triggered the current actor. Messages are thread local so this returns ``None`` when called outside of actor code. """ return cls._MESSAGE.get()
[docs] def before_process_message(self, broker, message): self._MESSAGE.set(message)
[docs] def after_process_message(self, broker, message, *, result=None, exception=None): self._MESSAGE.set(None)