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logging.config.dictConfig shuts down socket for existing SysLogHandlers #87362
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flyte commented
on Feb 10, 2021 flytemannequinMannequinAuthorSince b6c1989 dictConfig (and presumably fileConfig) has called logging.shutdown() on the existing handlers.
This causes existing SysLogHandlers' sockets to be closed, which then causes a BadFileDescriptor error when you try to use it:
--- Logging error ---
Traceback (most recent call last): File "/usr/lib/python3.8/logging/handlers.py", line 940, in emit self.socket.sendto(msg, self.address) OSError: [Errno 9] Bad file descriptor Call stack: File "/home/flyte/workspaces/python/test.py", line 18, in <module> log.warning("Breaks")
Reproduce the error with the following code:
import logging.config import socket from logging.handlers import SysLogHandler log = logging.getLogger("logtest") syslog_handler = SysLogHandler(("127.0.0.1", 12345), socktype=socket.SOCK_DGRAM) log.addHandler(syslog_handler) log.warning("Works") logging.config.dictConfig( { "version": 1, "disable_existing_loggers": False, } ) log.warning("Breaks")
This causes issues such as benoitc/gunicorn#2073 where gunicorn sets up a SysLogHandler, then when any app (Django does it by default) calls dictConfig() it closes the socket used by gunicorn's SysLogHandler.
Assuming this also affects Python 3.9 and 3.10, but untested.
I'm not getting this error on 3.11 on a Mac. Can you check on versions <= 3.9? Earlier versions are no longer getting bugfixes.
sblondon commented
on Jan 22, 2022 sblondonmannequinMannequinI can reproduce the error on Debian/testing with:
- Python 3.9.9
- Python 3.10.0
Reacted by Sahil SanganiOut of curiosity, what is messy about backporting this?
In figuring out that this was the problem, I touched
logging.pyquite a bit. I don't see any reason why the changes in #26490 couldn't be backported, at least not at the code level... Naturally, my perspective here is limited to my one application and not the entire CPython codebase and its millions of dependent projects, so if that's where the mess is then I understand. Again, just curious 😄If anyone else ran into this issue, can't upgrade to 3.11 right away, and needs a workaround, I had success with copy/pasting the code out of the PR into a class definition that subclasses
SysLogHandlerwith one small modification and it works fine so far. The only change in my subclass from what's in the PR is to theemitmethod:class FixedSysLogHandler(SysLogHandler): ... def emit(self, record): if not self.socket: self.createSocket() super().emit(record)
The methods
createSocket,close, and__init__are verbatim copies of the PR and everything else is inherited fromSysLogHandler. This has at least allowed it to work in iPython (which uses dictConfig and kills the socket on start-up) with 3.8.Hey @MajorDallas
can you please explain your solution for Python 3.8 version. I have situation where I can't upgrade to Python 3.11.
Question:
(1) Do I need to copyFixedSysLogHandlerand place it to logging.py only?
(2) If possible, can you share entire logging.py file to understand properly ?Thank you!
I did not modify
logging.py(other than forprint-debugging while tracking down the problem).Instead, in a utilities module in my app, I subclassed
SysLogHandlerand used that subclass as a drop-in replacement. As I said above, most of it is copied (almost) verbatim from Pull Request #26490, specifically the methods named above from the originalSysLogHandlerclass definition that starts at handlers.py:709 in the PR.YMMV. This worked with the
SysLogHandleras defined for Python 3.8; it may or may not work with other versions in the same way and I can't offer any support for it if it doesn't work for you.# Assume this file is 'app/utils/logging.py' from logging.handlers import SysLogHandler as OgSysLogHandler class SysLogHandler(OgSysLogHandler): def __init__( self, address=("localhost", 514), facility=OgSysLogHandler.LOG_USER, socktype=None, ): logging.Handler.__init__(self) self.address = address self.facility = facility self.socktype = socktype self.socket = None self.createSocket() def close(self): self.acquire() try: sock = self.socket if sock: self.socket = None sock.close() logging.Handler.close(self) finally: self.release() def createSocket(self): address = self.address socktype = self.socktype if isinstance(address, str): self.unixsocket = True # Syslog server may be unavailable during handler initialisation. # C's openlog() function also ignores connection errors. # Moreover, we ignore these errors while logging, so it not worse # to ignore it also here. try: self._connect_unixsocket(address) except OSError: pass else: self.unixsocket = False if socktype is None: socktype = socket.SOCK_DGRAM host, port = address ress = socket.getaddrinfo(host, port, 0, socktype) if not ress: raise OSError("getaddrinfo returns an empty list") for res in ress: af, socktype, proto, _, sa = res err = sock = None try: sock = socket.socket(af, socktype, proto) if socktype == socket.SOCK_STREAM: sock.connect(sa) break except OSError as exc: err = exc if sock is not None: sock.close() if err is not None: raise err self.socket = sock self.socktype = socktype def emit(self, record): if not self.socket: self.createSocket() super().emit(record)
Then, anywhere in your app where you currently have
from logging.handlers import SysLogHandler, just change that tofrom app.utils.logging import SysLogHandler(or whatever you make the module path on your machine). You shouldn't have to change any other code that's already trying to useSysLogHandler.Reacted by Mark and 김성겸Thank you! @MajorDallas
Reacted by MajorDallas
Note: these values reflect the state of the issue at the time it was migrated and might not reflect the current state.
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