tasks.py

from celery import Celery
from celery.loaders.base import BaseLoader
from raven import Client
from raven.contrib.celery import register_signal
from webapp import settings
from webapp.app import create_app


class CeleryLoader(BaseLoader):
    def __init__(self, app, **kwargs):
        super(CeleryLoader, self).__init__(app, **kwargs)
        self.flask_app = None

    # noinspection PyPep8Naming
    def on_worker_init(self):
        TaskBase = self.app.Task

        class ContextTask(TaskBase):
            abstract = True

            def __call__(self, *args, **kwargs):
                with self.flask_app.app_context():
                    return TaskBase.__call__(self, *args, **kwargs)

        self.app.Task = ContextTask
        self.flask_app = create_app(db_only=True)

        if settings.SENTRY_DSN:
            client = Client(settings.SENTRY_DSN)
            register_signal(client)

    def on_task_init(self, task_id, task):
        task.flask_app = self.flask_app


def celery_app():
    capp = Celery(loader=CeleryLoader)
    capp.config_from_object(settings)
    return capp

celery = celery_app()