Source code for airflow.providers.celery.sensors.celery_queue

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from __future__ import annotations

from typing import TYPE_CHECKING

from celery.app import control

from airflow.sensors.base import BaseSensorOperator

if TYPE_CHECKING:
    from airflow.utils.context import Context


[docs]class CeleryQueueSensor(BaseSensorOperator): """ Waits for a Celery queue to be empty. By default, in order to be considered empty, the queue must not have any tasks in the ``reserved``, ``scheduled`` or ``active`` states. :param celery_queue: The name of the Celery queue to wait for. :param target_task_id: Task id for checking """ def __init__(self, *, celery_queue: str, target_task_id: str | None = None, **kwargs) -> None: super().__init__(**kwargs) self.celery_queue = celery_queue self.target_task_id = target_task_id def _check_task_id(self, context: Context) -> bool: """ Get the Celery result from the Airflow task ID and return True if the result has finished execution. :param context: Airflow's execution context :return: True if task has been executed, otherwise False """ ti = context["ti"] celery_result = ti.xcom_pull(task_ids=self.target_task_id) return celery_result.ready()
[docs] def poke(self, context: Context) -> bool: if self.target_task_id: return self._check_task_id(context) inspect_result = control.Inspect() reserved = inspect_result.reserved() scheduled = inspect_result.scheduled() active = inspect_result.active() try: reserved = len(reserved[self.celery_queue]) scheduled = len(scheduled[self.celery_queue]) active = len(active[self.celery_queue]) self.log.info("Checking if celery queue %s is empty.", self.celery_queue) return reserved == 0 and scheduled == 0 and active == 0 except KeyError: message = f"Could not locate Celery queue {self.celery_queue}" raise KeyError(message)

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