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severb / graypy

Python logging handler for Graylog that sends messages in GELF (Graylog Extended Log Format).
https://www.graylog.org/
BSD 3-Clause "New" or "Revised" License
258 stars 90 forks source link

warnings.warn print whole overflowing message, I think this is a bug #134

Open MajorAdam opened 2 years ago

MajorAdam commented 2 years ago

https://github.com/severb/graypy/blob/a5a82c535002db6015473cb59a7476361060d358/graypy/handler.py#L467

nklapste commented 2 years ago

Thanks for pointing this out!

Normally, Python warnings should be only be written out to sys.stderr and are normally not logged by Python's standard logging. As such, the warning message created by this call (containing the whole GELF overflowing message) would not be logged by graypy and would be only visible on sys.stderr.

However, there is an exception to this, if logging.captureWarnings(capture=True) is called and the py.warnings logger was configured to have a graypy logging handler added. This will enable Python's logging to capture and log these overflowing warnings with graypy which then proceeds to infinitely recurse. To avoid this infinite recursion you can ignore GELFChunkOverflowWarning warnings with prefixing your code with:

warnings.filterwarnings("ignore", category=GELFChunkOverflowWarning)

Note, doing this will silently ignore any overflowing message warnings. And if using the GELFWarningChunker you will have no indication in either sys.stderr or your Graylog logs that a overflowing message was dropped.

I'll take a look if a mitigation can be made for when logging.captureWarnings(capture=True) is set. But, otherwise on normal Python logging instances this warning should not cause issues.