芹菜和弦回调on_error缺少参数

Question

TypeError： on_chord_error(( 缺少 2 个必需的位置参数："exc"和"traceback"。

使用芹菜 4.3.0

阅读本文档 https://docs.celeryproject.org/en/latest/userguide/canvas.html#chords

chord_head_list = (add.s(i, i) for i in range(4))
    res_chord = (group(chord_head_list) | callback.s().on_error(on_chord_error.s())).delay()
print(res_chord.get(timeout=20))

@app.task(name='tasks.callback')
def callback(result):
    print('>>>>>>>>>>>>>>>>> callback {0}'.format(result))
    return result

@app.task(name='tasks.on_chord_error')
def on_chord_error(request, exc, traceback):
    print('>>>>>>>>>>>>>>>>> Task {0!r} raised error: {1!r}'.format(request.id, exc))

Answer 1

Celery 文档存在问题：https://github.com/celery/celery/issues/3709
您应该更改错误回调参数：

@app.task(bind=True, name='tasks.on_chord_error')
def on_chord_error(self, failed_task_id, param1, param2):
    print(f"failed_task_id {failed_task_id}")

或：

@app.task(name='tasks.on_chord_error')
def on_chord_error(*args, **kwargs):
    print(f"args={args}, kwargs={kwargs}")

我仍然缺少和弦组结果