Path: csiph.com!usenet.pasdenom.info!gegeweb.org!de-l.enfer-du-nord.net!feeder1.enfer-du-nord.net!feeds.phibee-telecom.net!newsfeed.xs4all.nl!newsfeed6.news.xs4all.nl!xs4all!post.news.xs4all.nl!not-for-mail Return-Path: X-Original-To: python-list@python.org Delivered-To: python-list@mail.python.org X-Spam-Status: OK 0.006 X-Spam-Evidence: '*H*': 0.99; '*S*': 0.00; 'subject:: [': 0.03; 'subject:Python': 0.05; 'subject:file': 0.07; 'subject:How': 0.09; 'expected.': 0.09; 'throw': 0.09; 'file,': 0.15; 'sat,': 0.15; 'slightly': 0.15; 'from:addr:rosuav': 0.16; 'from:name:chris angelico': 0.16; 'posix': 0.16; 'rotation': 0.16; 'truncating': 0.16; 'wrote:': 0.17; 'instance,': 0.17; 'subject:] ': 0.19; 'windows': 0.19; 'file.': 0.20; 'error.': 0.21; 'received:209.85.214.174': 0.21; 'header:In-Reply-To:1': 0.25; 'am,': 0.27; 'handling': 0.27; 'message-id:@mail.gmail.com': 0.27; 'probably': 0.29; 'towards': 0.32; 'file': 0.32; 'to:addr:python- list': 0.33; 'received:google.com': 0.34; 'exist': 0.35; 'fresh': 0.35; 'open': 0.35; 'received:209.85': 0.35; 'there': 0.35; 'but': 0.36; 'anything': 0.36; 'should': 0.36; 'possible': 0.37; 'moment': 0.37; 'received:209': 0.37; 'subject:: ': 0.38; 'perform': 0.38; 'several': 0.39; 'to:addr:python.org': 0.39; 'received:209.85.214': 0.39; 'application': 0.40; 'header:Received:5': 0.40; 'matter': 0.61; 'close': 0.63; 'different': 0.63; 'more': 0.63; 'else.': 0.65; 'jul': 0.65; 'saving': 0.72; 'lean': 0.84; 'subject:status': 0.84 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :content-type; bh=21TyRgMQWAn7p6K5vfr14gyYzaabWwqvmzimwn1Tl4Y=; b=xm6X5sTlWQXvgbJvOL9tA31qo5a7kQWuik8LcQy/pBpMWEZHm2knpCfwV+tXem11uO 6rlcHtlJb7E2CqQgQ8bjIKiSG9jo812cP4qkIZRmFBYNxemgxRBfJ2Huvl4G7Di5gpVu Hne//HbCpLBNBk+XrtsaxBwfbYoEX09m5C5wdBfu3z6Jt7ecFQzW11+W1PmfIOOARZgn a1GfLLEdYfp0f0JXibwb6NvtQELC3rJMB4Ccl4gD4FQfca0tyNwIzukZowZAP0nS+aMu 5uV0NKBjCGYPEcTyW4iCWMkwwc9Xy+vsdlYf7t/ku39YSldjU94KtR12OAcVzzK97q2/ mhvQ== MIME-Version: 1.0 In-Reply-To: <5B80DD153D7D744689F57F4FB69AF474165562E0@SCACMX008.exchad.jpmchase.net> References: <4FF9F454.40207@shopzeus.com> <4ffecef4$0$6877$e4fe514c@news2.news.xs4all.nl> <4FFF0CB7.3030007@shopzeus.com> <4fff926b$0$29965$c3e8da3$5496439d@news.astraweb.com> <62e90523-a160-4e28-8109-9ce32d8952e1@googlegroups.com> <5B80DD153D7D744689F57F4FB69AF474165560E7@SCACMX008.exchad.jpmchase.net> <50005A96.3010305@gonnerman.org> <5B80DD153D7D744689F57F4FB69AF474165562E0@SCACMX008.exchad.jpmchase.net> Date: Sat, 14 Jul 2012 04:19:24 +1000 Subject: Re: [Python] RE: How to safely maintain a status file From: Chris Angelico To: python-list@python.org Content-Type: text/plain; charset=ISO-8859-1 X-BeenThere: python-list@python.org X-Mailman-Version: 2.1.12 Precedence: list List-Id: General discussion list for the Python programming language List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Newsgroups: comp.lang.python Message-ID: Lines: 17 NNTP-Posting-Host: 2001:888:2000:d::a6 X-Trace: 1342203567 news.xs4all.nl 6856 [2001:888:2000:d::a6]:53672 X-Complaints-To: abuse@xs4all.nl Xref: csiph.com comp.lang.python:25282 On Sat, Jul 14, 2012 at 3:59 AM, Prasad, Ramit wrote: > I lean slightly towards the POSIX handling with the addition that > any additional write should throw an error. You are now saving to > a file that will not exist the moment you close it and that is probably > not expected. There are several different possible "right behaviors" here, but they depend more on the application than anything else. With a log file, for instance, the act of deleting it is more a matter of truncating it (dispose of the old history), so the right thing to do is to start a fresh file. Solution: Close the file and re-open it periodically. But I don't know of an efficient way to do that with Windows semantics. Renaming/moving an open file in order to perform log rotation isn't all that easy. ChrisA