Re: [log4perl-devel] log4perl causing perl process to die (fwd)

[Mike S. <m...@pe...>]

On Sun, 4 Nov 2007, Strahan, Bob wrote:

> We do use the 'close_after_write' option... As I mentioned, there are
> multiple concurrent processes continually being spawned by the
> service, each using log4perl to log to the same logfile.  So we
> figured we needed to use File::Locked along with close_after_write to
> ensure each process got an exclusive lock on the logfile before
> writing to it.

I see -- the recommended ways of synchronizing access to an appender are
listed in the Log4perl FAQ:

    http://log4perl.sourceforge.net/d/Log/Log4perl/FAQ.html#23804

I'm not sure how well they work on Windows, though, but give the
'syswrite' option a try, that should be the easiest.

-- Mike

Mike Schilli
m...@pe...

> Let me know if there is a better (more efficient) way to handle
> multiple concurrent processes logging to the same file e.g. Would
> using socket appenders to route log messages to single log server
> process which handles file i/o from one process be a better option?
>
>
> > Which version of Windows are you running by the way? On regular XP, it
> > seems to work as expected.
>
> Windows 2003 64-bit server..  I haven't tried it on other flavors of Windows.
>
>
> For now I have worked around the problem by inserting the open() call into a retry loop..
>     #open $fh, "$self->{mode}$self->{filename}"
>     #    or die "Cannot write to '$self->{filename}': $!";
>     while (1) {
>        last if open $fh, "$self->{mode}$self->{filename}" ;
>     }
>
>
>
>
>
>
>
>
> -----Original Message-----
> From: log...@li... [mailto:log...@li...] On Behalf Of Mike Schilli
> Sent: Saturday, November 03, 2007 6:32 PM
> To: Mike Schilli
> Cc: log...@li...
> Subject: Re: [log4perl-devel] log4perl causing perl process to die (fwd)
>
> On Fri, 2 Nov 2007, Bob Strahan wrote:
>
> > However, it seems that if certain filesystem operations are
> > performed on the logfile it can cause the logger to execute die(),
> > causing my service to die, with the following error
> >
> > Cannot write to 'D:/Program Files (x86)/My App/logs/logfile.txt':
> > Permission denied at D:\Program Files (x86)\My
> > App\lib\perllibs\lib/Log/Dispatch/File.pm line 86.
>
> Hmm, this is Log::Dispatch::File's _open_file() function complaining
> that an open() failed. Does your service open a files after it's been
> running for a while? Typically, Log::Dispatch::File(::Locked) opens the
> file only once unless 'close_after_write' is given.
>
> Which version of Windows are you running by the way? On regular XP, it
> seems to work as expected.
>
> -- Mike
>
> Mike Schilli
> m...@pe...
>
> > I am using log4perl in a Win32 service that needs to run forever..  However, I have encountered a situation where the logger call is executing a die() and causing my service to die...
> >
> >
> > The service spawns multiple child processes which run concurrently but all log to the same logfile.. We're using File::Locked to avoid contention..  Extract from our logger config below..
> >
> > "log4perl.appender.myapp" => "Log::Dispatch::File::Locked",
> > "log4perl.appender.myapp.filename" => "D:/Program Files (x86)/My App/logs/logfile.txt",
> > "log4perl.appender.myapp.mode" => "append",
> > "log4perl.appender.myapp.close_after_write" => "true",
> > "log4perl.appender.myapp.permissions" => "0660",
> > Etc..
> >
> >
>
> > I can reproduce the problem sporadically by simply opening the logfile in Wordpad..
> > I can reproduce it reliably by repeatedly copying the logfile using test script below
> >
> > #!perl -w
> > use File::Copy ;
> > while (1) {
> >    copy ("D:/Program Files (x86)/My App/logs/logfile.txt", "D:/Program Files (x86)/My App/logs/logfileCOPY.txt") ;
> >    print "." ;
> > }
> >
> >
> > Any suggestions on how to defend against users copying or opening the logfile?   We should block and retry until open() suceeds, rather than die(), I think.
> >
> > Please let me know if you can help with a patch, workaround, or suggestion.
> >
> > Regards
> >
> >
> >
> > Bob Strahan
> > HP Software, R&D
> >
> > 703.579.1929 office | 702.967.5228 mobile | 702.579.1929 fax | bob...@hp...<mailto:bob...@hp...>
> > 10700 Parkridge Blvd. #500 | Reston | VA 20191
> >
> >
> > -------------------------------------------------------------------------
> > This SF.net email is sponsored by: Splunk Inc.
> > Still grepping through log files to find problems?  Stop.
> > Now Search log events and configuration files using AJAX and a browser.
> > Download your FREE copy of Splunk now >> http://get.splunk.com/
> > _______________________________________________
> > log4perl-devel mailing list
> > log...@li...
> > https://lists.sourceforge.net/lists/listinfo/log4perl-devel
> >
>
> -------------------------------------------------------------------------
> This SF.net email is sponsored by: Splunk Inc.
> Still grepping through log files to find problems?  Stop.
> Now Search log events and configuration files using AJAX and a browser.
> Download your FREE copy of Splunk now >> http://get.splunk.com/
> _______________________________________________
> log4perl-devel mailing list
> log...@li...
> https://lists.sourceforge.net/lists/listinfo/log4perl-devel
>