芹菜不是简单的印刷品

我有一个芹菜的helloworld类型函数:

from celery import Celery
import time
app = Celery('test_celery',
             broker= 'amqp://celeryuser:pass@ip:5672/celeryvhost',
             )

@app.task
def add(x, y):
    time.sleep(2)
    print('calculating something aaewsome --------------------')
    return x + y

if __name__ == '__main__':
    result = add.delay(4, 4)
    print( result.get() )

我运行命令以运行任务:

celery -A test_celery worker --loglevel=info

我得到输出:

[tasks]
  . test_celery.add
[2018-07-17 00:17:40,668: INFO/MainProcess] Connected to amqp://celeryuser:**@myip:5672/celeryvhost
[2018-07-17 00:17:40,679: INFO/MainProcess] mingle: searching for neighbors
[2018-07-17 00:17:41,705: INFO/MainProcess] mingle: sync with 1 nodes
[2018-07-17 00:17:41,706: INFO/MainProcess] mingle: sync complete
[2018-07-17 00:17:41,725: INFO/MainProcess] celery@www.mysite.com ready.

在日志中显示:

[2018-07-17 00:17:40,698: INFO/MainProcess] sync with celery@mysite.com

但没有输出指纹。

我做错什么了?