The comment explains this issue, but effectively, the upgrade to
Django 2.x means that Django's built-in django.request logger was
writing to our errors logs WARNING-level data for every 404 and 400
error. We don't consider user errors to be a problem worth
highlighting in that log file.
We have a very useful piece of code, _RateLimitFilter, which is
designed to avoid sending us a billion error emails in the event that
a Zulip production server is down in a way that throws the same
exception a lot. The code uses memcached to ensure we send each
traceback roughly once per Zulip server per 10 minutes (or if
memcached is unavailable, at most 1/process/10 minutes, since we use
memcached to coordinate between processes)
However, if memcached is down, there is a logging.error call internal
to the Django/memcached setup that happens inside the cache.set() call,
and those aren't caught by the `except Exception` block around it.
This ends up resulting in infinite recursion, eventually leading to
Fatal Python error: Cannot recover from stack overflow., since this
handler is configured to run for logging.error in addition to
logging.exception.
We fix this using a thread-local variable to detect whether we are
being called recursively.
This change should prevent some nasty failure modes we've had in the
past where memcached being down resulted in infinite recursion
(resulting in extra resources being consumed by our error
notifications code, and most importantly, the error notifications not
being sent).
Fixes#12595.
The name `create_logger` suggests something much bigger than what this
function actually does -- the logger doesn't any more or less exist
after the function is called than before. Its one real function is to
send logs to a specific file.
So, pull out that logic to an appropriately-named function just for
it. We already use `logging.getLogger` in a number of places to
simply get a logger by name, and the old `create_logger` callsites can
do the same.
From the docs:
> This function does nothing if the root logger already has handlers
> configured for it.
Which we do if we've started up Django and configured settings, and in
particular allowed Django to process `settings.LOGGING`.
So, cut it out -- all it can do is confuse people about how logging
works.
If we ever actually used the `log_format` parameter, this would be
doubly confused, because only the first call would have any effect.
Because calls to `create_logger` generally run after settings are
configured, these would override what we have in `settings.LOGGING` --
which in particular defeated any attempt to set log levels in
`test_settings.py`. Move all of these settings to the same place in
`settings.py`, so they can be overridden in a uniform way.
This is already the loglevel we set on the root logger, so this has no
effect -- except in tests, where `test_settings.py` attempts to set
some of these same loggers to higher loglevels. Because the
`create_logger` call generally runs after we've configured settings,
it clobbers that effect.
The code in `test_settings.py` that tries to suppress logs only works
because it also sets `propagate=False`, which has nothing to do with
loglevels but does cause logs at this logger (and descendants) to be
dropped completely unless we've configured handlers for this logger
(or one of its relevant descendants.)
These are long enough to still be self-explanatory (the only one I'm
at all in doubt about there is DEBG; I avoided "DBUG" because it reads
"BUG" which suggests a high-priority message, and those are the
opposite of that), while saving a good bit of horizontal space
vs. padding everything to the 8 characters of "CRITICAL".
Also add a linter exception to allow easy-to-read alignment here,
similar to several existing exceptions for other alignment cases.
This also gives us a place to hang the originating module, if we write a bit
of logic to work that out; sadly it doesn't come out of the box, only
the filename (which is likely to have a bunch of noise that just shows the
path to the deployment or virtualenv.)
This doesn't yet do much, but it gives us a suitable place to
add code to customize how log messages are displayed, beyond what
a format string passed to the default formatter can do.
Our implementation of duplication detection in the Zulip email error
reporting system was buggy in two important ways:
* It did not look at the traceback, and thus considered all errors as
the same.
* It reset the 10-minute duplicate timer every time an error happened,
thus concealing situations where the same error was occuring more
often than 1/10 minutes.
Also, fixed a a small type annotation in users.py because email must
be a string because emails don't support UTF-8 at this time (according
a comment in gravatar_hash in avatar.py).
Anders Kaseorg
Mateusz Mandera
Tim Abbott
Greg Price
rht
Steve Howell
Aditya Bansal
hackerkid
Rishi Gupta
Umair Khan
sinwar
nikolay
Tommy Ip
Max
David Roe
Luke Faraone
Tim Abbott