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Path: ...!weretis.net!feeder8.news.weretis.net!fu-berlin.de!uni-berlin.de!not-for-mail From: Left Right <olegsivokon@gmail.com> Newsgroups: comp.lang.python Subject: Re: FileNotFoundError thrown due to file name in file, rather than file itself Date: Mon, 11 Nov 2024 17:04:52 +0100 Lines: 80 Message-ID: <mailman.92.1731341107.4695.python-list@python.org> References: <87v7wt986z.fsf@zedat.fu-berlin.de> <CAJQBtg=UOiOmmHa25EUZtrZO19F1O0_VxCO6gWjZ5ebAMHnXCA@mail.gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Trace: news.uni-berlin.de 7Q4FlMQx4wbszB5QStolGwDBAnR1BSEWRjouw2pOoaGg== Cancel-Lock: sha1:hpDTbC/TzYBM8Qabkh4pS4T4txQ= sha256:fgdM3dImhvZEbb3VmhmFTsHJlNZNITepqSmLRgJiLKs= Return-Path: <olegsivokon@gmail.com> X-Original-To: python-list@python.org Delivered-To: python-list@mail.python.org Authentication-Results: mail.python.org; dkim=pass reason="2048-bit key; unprotected key" header.d=gmail.com header.i=@gmail.com header.b=XnBcuM1x; 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Python is not anything special in this case. Of course, it would've been better if the error reported what file wasn't found. But, usually these problems are stacking, like in your code. Unfortunately, it's your duty, as the language user, to anticipate those problems and act accordingly. Now you've learned that the one file you believe that could be the source for the error isn't the only one--well, adjust your code to differentiate between those two (and potentially other?) cases. There's very little else you can do beside that. NB. On the system level, the error has no information about what file wasn't found. It simply returns some numeric value (the famous ENOENT) in case when the system call to open a file fails. Python could've been more helpful by figuring out what path caused the problem and printing that in the error message, but it doesn't... That's why I, myself, never use the vanilla FileNotFoundError, I always re-rise it with a customized version that incorporates the information about the missing file in the error message. NB2. It's always a bad idea to print logs to files. Any sysadmin / ops / infra person worth their salt will tell you that. The only place the logs should go to is the standard error. There are true and tried tools that can pick up logs from that point on, and do with them whatever your heart desires. That is, of course, unless you are creating system tools for universal log management (in which case, I'd question the choice of Python as a suitable language for such a task). Unfortunately, even though this has been common knowledge for decades, it's still elusive in the world of application development :| On Mon, Nov 11, 2024 at 4:00=E2=80=AFPM Loris Bennett via Python-list <python-list@python.org> wrote: > > Hi, > > I have the following in my program: > > try: > logging.config.fileConfig(args.config_file) > config =3D configparser.ConfigParser() > config.read(args.config_file) > if args.verbose: > print(f"Configuration file: {args.config_file}") > except FileNotFoundError: > print(f"Error: configuration file {args.config_file} not found. = Exiting.") > sys.exit(0) > > and when I ran the program I got the error > > Error: configuration file /usr/local/etc/sc_mailer not found. Exiting. > > However, this file *does* exist and *can* be read. By checking the > 'filename' attribute of the exception I discovered that the problem was > the log file defined *in* the config file, namely > > [handler_fileHandler] > class=3DFileHandler > level=3DDEBUG > formatter=3DdefaultFormatter > args=3D('/var/log/my_prog.log', 'a') > > This log file did not exist. The exception is thrown by > > logging.config.fileConfig(args.config_file) > > My questions are: > > 1. Should I be surprised by this behaviour? > 2. In terms of generating a helpful error message, how should one > distinguish between the config file not existing and the log file not > existing? > > Cheers, > > Loris > > -- > This signature is currently under constuction. > -- > https://mail.python.org/mailman/listinfo/python-list