Source code for dramatiq.middleware.callbacks

# This file is a part of Dramatiq.
#
# Copyright (C) 2017,2018 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/>.

from .middleware import Middleware




class Callbacks(Middleware):
    """Middleware that lets you chain success and failure callbacks
    onto Actors.

    Parameters:
      on_failure(str): The name of an actor to send a message to on
        failure.
      on_success(str): The name of an actor to send a message to on
        success.
    """

    @property
    def actor_options(self):
        return {
            "on_failure",
            "on_success",
        }

    def after_process_message(self, broker, message, *, result=None, exception=None):
        actor = broker.get_actor(message.actor_name)
        if exception is None:
            target_actor_name = message.options.get("on_success") or actor.options.get("on_success")
            if target_actor_name:
                target_actor = broker.get_actor(target_actor_name)
                target_actor.send(message.asdict(), result)

        else:
            target_actor_name = message.options.get("on_failure") or actor.options.get("on_failure")
            if target_actor_name:
                target_actor = broker.get_actor(target_actor_name)
                target_actor.send(message.asdict(), {
                    "type": type(exception).__name__,
                    "message": str(exception),
                })