How do I prevent duplicate celery logs in an application like this?
# test.py
from celery import Celery
import logging
app = Celery('tasks', broker='redis://localhost:6379/0')
app.logger = logging.getLogger("new_logger")
file_handler = logging.handlers.RotatingFileHandler("app.log", maxBytes=1024*1024, backupCount=1)
file_handler.setFormatter(logging.Formatter('custom_format %(message)s'))
app.logger.addHandler(file_handler)
@app.task
def foo(x, y):
app.logger.info("log info from foo")
I start the application with: celery -A test worker --loglevel=info --logfile celery.log
Then I cause foo to be run with python -c "from test import foo; print foo.delay(4, 4)"
This results in the "log info from foo" being displayed in both celery.log and app.log.
Here is app.log contents:
custom_format log info from foo
And here is celery.log contents:
[2017-07-26 21:17:24,962: INFO/MainProcess] Connected to redis://localhost:6379/0
[2017-07-26 21:17:24,967: INFO/MainProcess] mingle: searching for neighbors
[2017-07-26 21:17:25,979: INFO/MainProcess] mingle: all alone
[2017-07-26 21:17:25,991: INFO/MainProcess] celery@jd-t430 ready.
[2017-07-26 21:17:38,224: INFO/MainProcess] Received task: test.foo[e2c5e6aa-0d2d-4a16-978c-388a5e3cf162]
[2017-07-26 21:17:38,225: INFO/ForkPoolWorker-4] log info from foo
[2017-07-26 21:17:38,226: INFO/ForkPoolWorker-4] Task test.foo[e2c5e6aa-0d2d-4a16-978c-388a5e3cf162] succeeded in 0.000783085000876s: None
I considered removing the custom logger handler from the python code, but I don't want to just use celery.log because it doesn't support rotating files. I considered starting celery with --logfile /dev/null but then I would loose the mingle and other logs that don't show up in app.log.
Can I prevent "log info from foo" from showing up in celery.log? Given that I created the logger from scratch and only setup logging to app.log why is "log info from foo" showing up in celery.log anyway?
Is it possible to get the celery MainProcess and Worker logs (e.g. Connected to redis://localhost:6379/0) to be logged by a RotatingFileHandler (e.g. go in my app.log)?