Celery expects to manage pretty much everything, including logging. It

sets up logging handlers, formatting, etc., and it does this very

shortly before it begins registering queues and displaying the initial

sort of splash screen that lists them.
Any code that attempts to register a logger prior to this will fail, and

any top-level log statements being executed (including our dependency

warnings for tools) will use the default logger with the default

formatting and not acknowledge any filters or log files passed to

Celery.
While not terribly well-documented, Celery does support a number of

signal handlers that allow for performing operations during setup. We

now listen to one of these, celeryd_after_setup, and perform our own

configuration loading and dependency checks here.
We also set the queues here, which we can do by setting a property. This

is supported in the public API (intended for dynamic queue computation),

and is equivalent to what happens when setting the configuration

up-front.

Tested launching Review Bot on both Python 2.7 (with Celery 3.x) and

Python 3 (with Celery 4.x). Verified in both cases that logging was

properly set up, logging statements from dependency checks and upcoming

code was formatted properly and reacted to Celery log configuration,

and that queues for tools were properly registered.