Celery ValueError: not enough values to unpack (expected 3, got 0)的解決方案

工作的環境版本如下：

【Django version】: 2.1

【celery version】：4.4.0rc2

【python version】: 3.7

【Redis version】：3.2.1

啟動celery沒有報錯，但是執行隊列任務的時候就爆出下的錯誤：

C:\Users\Circle\Desktop\circle\dailyfresh>celery -A celery_tasks.tasks worker -l info

 -------------- celery@DESKTOP-9T9MK4N v4.4.0rc2 (cliffs)
---- **** -----
--- * ***  * -- Windows-10-10.0.18362-SP0 2019-07-07 18:30:46
-- * - **** ---
- ** ---------- [config]
- ** ---------- .> app:         celery_tasks.tasks:0x3f1dbd0
- ** ---------- .> transport:   redis://127.0.0.1:6379/0
- ** ---------- .> results:     disabled://
- *** --- * --- .> concurrency: 6 (prefork)
-- ******* ---- .> task events: OFF (enable -E to monitor tasks in this worker)
--- ***** -----
 -------------- [queues]
                .> celery           exchange=celery(direct) key=celery


[tasks]
  . celery_tasks.tasks.send_register_active_email

[2019-07-07 18:30:46,878: INFO/MainProcess] Connected to redis://127.0.0.1:6379/0
[2019-07-07 18:30:46,895: INFO/MainProcess] mingle: searching for neighbors
[2019-07-07 18:30:47,095: INFO/SpawnPoolWorker-1] child process 13392 calling self.run()
[2019-07-07 18:30:47,107: INFO/SpawnPoolWorker-2] child process 14868 calling self.run()
[2019-07-07 18:30:47,120: INFO/SpawnPoolWorker-3] child process 9888 calling self.run()
[2019-07-07 18:30:47,142: INFO/SpawnPoolWorker-4] child process 2376 calling self.run()
[2019-07-07 18:30:47,163: INFO/SpawnPoolWorker-5] child process 11940 calling self.run()
[2019-07-07 18:30:47,281: INFO/SpawnPoolWorker-6] child process 13064 calling self.run()
[2019-07-07 18:30:47,913: INFO/MainProcess] mingle: all alone
[2019-07-07 18:30:47,920: INFO/MainProcess] celery@DESKTOP-9T9MK4N ready.
[2019-07-07 18:32:59,122: INFO/MainProcess] Received task: celery_tasks.tasks.send_register_active_email[3a441c20-162b-441c-902c-d479b8450115]
[2019-07-07 18:32:59,129: ERROR/MainProcess] Task handler raised error: ValueError('not enough values to unpack (expected 3, got 0)')
Traceback (most recent call last):
  File "c:\users\circle\appdata\local\programs\python\python37-32\lib\site-packages\billiard\pool.py", line 358, in workloop
    result = (True, prepare_result(fun(*args, **kwargs)))
  File "c:\users\circle\appdata\local\programs\python\python37-32\lib\site-packages\celery\app\trace.py", line 546, in _fast_trace_task
    tasks, accept, hostname = _loc
ValueError: not enough values to unpack (expected 3, got 0)

一頓亂找之后，發現有人說在win10上運行celery4.x版本就會出現這個問題，解決辦法是安裝一個eventlet

pip install eventlet

再次啟動celery執行任務：

celery -A celery_tasks.tasks worker -l info -P eventlet 

再次執行任務也沒有報錯

C:\Users\Circle\Desktop\circle\dailyfresh>celery -A celery_tasks.tasks worker -l info -P eventlet
-------------- celery@DESKTOP-9T9MK4N v4.4.0rc2 (cliffs)
--- * ***  * -- Windows-10-10.0.18362-SP0 2019-07-07 18:44:33
-- * - **** ---
- ** ---------- [config]
- ** ---------- .> app:         celery_tasks.tasks:0x472d2f0
- ** ---------- .> transport:   redis://127.0.0.1:6379/0
- ** ---------- .> results:     disabled://
- *** --- * --- .> concurrency: 6 (eventlet)
-- ******* ---- .> task events: OFF (enable -E to monitor tasks in this worker)
--- ***** -----
 -------------- [queues]
                .> celery           exchange=celery(direct) key=celery


[tasks]
  . celery_tasks.tasks.send_register_active_email

[2019-07-07 18:44:33,452: INFO/MainProcess] Connected to redis://127.0.0.1:6379/0
[2019-07-07 18:44:33,470: INFO/MainProcess] mingle: searching for neighbors
[2019-07-07 18:44:34,509: INFO/MainProcess] mingle: all alone
[2019-07-07 18:44:34,519: INFO/MainProcess] pidbox: Connected to redis://127.0.0.1:6379/0.
# 這下面爆了一個警告，但是不要在意，大概意思是你的DEBUG是調試模式，調試導致內存泄漏，請不要在生產環境中使用此設置!
[2019-07-07 18:44:34,523: WARNING/MainProcess] c:\users\circle\appdata\local\programs\python\python37-32\lib\site-packages\celery\fixups\django.py:202: UserWarning: Usi
ng settings.DEBUG leads to a memory leak, never use this setting in production environments!
  warnings.warn('Using settings.DEBUG leads to a memory leak, never '
[2019-07-07 18:44:34,523: INFO/MainProcess] celery@DESKTOP-9T9MK4N ready.
[2019-07-07 18:44:50,818: INFO/MainProcess] Received task: celery_tasks.tasks.send_register_active_email[ec83170e-05d5-412c-89e6-77699ade9f07]
[2019-07-07 18:44:57,435: INFO/MainProcess] Task celery_tasks.tasks.send_register_active_email[ec83170e-05d5-412c-89e6-77699ade9f07] succeeded in 6.625s: None