Appender::File(3pm) User Contributed Perl Documentation Appender::File(3pm)
NAME
Log::Log4perl::Appender::File - Log to file
SYNOPSIS
use Log::Log4perl::Appender::File;
my $app = Log::Log4perl::Appender::File->new(
filename => 'file.log',
mode => 'append',
autoflush => 1,
umask => 0222,
);
$file->log(message => "Log me\n");
DESCRIPTION
This is a simple appender for writing to a file.
The "log()" method takes a single scalar. If a newline character should
terminate the message, it has to be added explicitly.
Upon destruction of the object, the filehandle to access the file is
flushed and closed.
If you want to switch over to a different logfile, use the
"file_switch($newfile)" method which will first close the old file
handle and then open a one to the new file specified.
OPTIONS
filename
Name of the log file.
mode
Messages will be append to the file if $mode is set to the string
"append". Will clobber the file if set to "clobber". If it is
"pipe", the file will be understood as executable to pipe output
to. Default mode is "append".
autoflush
"autoflush", if set to a true value, triggers flushing the data out
to the file on every call to "log()". "autoflush" is on by default.
syswrite
"syswrite", if set to a true value, makes sure that the appender
uses syswrite() instead of print() to log the message. "syswrite()"
usually maps to the operating system's "write()" function and makes
sure that no other process writes to the same log file while
"write()" is busy. Might safe you from having to use other
synchronisation measures like semaphores (see: Synchronized
appender).
umask
Specifies the "umask" to use when creating the file, determining
the file's permission settings. If set to 0022 (default), new
files will be created with "rw-r--r--" permissions. If set to
0000, new files will be created with "rw-rw-rw-" permissions.
owner
If set, specifies that the owner of the newly created log file
should be different from the effective user id of the running
process. Only makes sense if the process is running as root. Both
numerical user ids and user names are acceptable. Log4perl does
not attempt to change the ownership of existing files.
group
If set, specifies that the group of the newly created log file
should be different from the effective group id of the running
process. Only makes sense if the process is running as root. Both
numerical group ids and group names are acceptable. Log4perl does
not attempt to change the group membership of existing files.
utf8
If you're printing out Unicode strings, the output filehandle needs
to be set into ":utf8" mode:
my $app = Log::Log4perl::Appender::File->new(
filename => 'file.log',
mode => 'append',
utf8 => 1,
);
binmode
To manipulate the output filehandle via "binmode()", use the
binmode parameter:
my $app = Log::Log4perl::Appender::File->new(
filename => 'file.log',
mode => 'append',
binmode => ":utf8",
);
A setting of ":utf8" for "binmode" is equivalent to specifying the
"utf8" option (see above).
recreate
Normally, if a file appender logs to a file and the file gets moved
to a different location (e.g. via "mv"), the appender's open file
handle will automatically follow the file to the new location.
This may be undesirable. When using an external logfile rotator,
for example, the appender should create a new file under the old
name and start logging into it. If the "recreate" option is set to
a true value, "Log::Log4perl::Appender::File" will do exactly that.
It defaults to false. Check the "recreate_check_interval" option
for performance optimizations with this feature.
recreate_check_interval
In "recreate" mode, the appender has to continuously check if the
file it is logging to is still in the same location. This check is
fairly expensive, since it has to call "stat" on the file name and
figure out if its inode has changed. Doing this with every call to
"log" can be prohibitively expensive. Setting it to a positive
integer value N will only check the file every N seconds. It
defaults to 30.
This obviously means that the appender will continue writing to a
moved file until the next check occurs, in the worst case this will
happen "recreate_check_interval" seconds after the file has been
moved or deleted. If this is undesirable, setting
"recreate_check_interval" to 0 will have the appender check the
file with every call to "log()".
recreate_check_signal
In "recreate" mode, if this option is set to a signal name (e.g.
"USR1"), the appender will recreate a missing logfile when it
receives the signal. It uses less resources than constant polling.
The usual limitation with perl's signal handling apply. Check the
FAQ for using this option with the log rotating utility
"newsyslog".
recreate_pid_write
The popular log rotating utility "newsyslog" expects a pid file in
order to send the application a signal when its logs have been
rotated. This option expects a path to a file where the pid of the
currently running application gets written to. Check the FAQ for
using this option with the log rotating utility "newsyslog".
create_at_logtime
The file appender typically creates its logfile in its constructor,
i.e. at Log4perl "init()" time. This is desirable for most use
cases, because it makes sure that file permission problems get
detected right away, and not after days/weeks/months of operation
when the appender suddenly needs to log something and fails because
of a problem that was obvious at startup.
However, there are rare use cases where the file shouldn't be
created at Log4perl "init()" time, e.g. if the appender can't be
used by the current user although it is defined in the
configuration file. If you set "create_at_logtime" to a true value,
the file appender will try to create the file at log time. Note
that this setting lets permission problems sit undetected until log
time, which might be undesirable.
header_text
If you want Log4perl to print a header into every newly opened (or
re-opened) logfile, set "header_text" to either a string or a
subroutine returning a string. If the message doesn't have a
newline, a newline at the end of the header will be provided.
mkpath
If this this option is set to true, the directory path will be
created if it does not exist yet.
mkpath_umask
Specifies the "umask" to use when creating the directory,
determining the directory's permission settings. If set to 0022
(default), new directory will be created with "rwxr-xr-x"
permissions. If set to 0000, new directory will be created with
"rwxrwxrwx" permissions.
Design and implementation of this module has been greatly inspired by
Dave Rolsky's "Log::Dispatch" appender framework.
LICENSE
Copyright 2002-2013 by Mike Schilli <m@perlmeister.com> and Kevin Goess
<cpan@goess.org>.
This library is free software; you can redistribute it and/or modify it
under the same terms as Perl itself.
AUTHOR
Please contribute patches to the project on Github:
http://github.com/mschilli/log4perl
Send bug reports or requests for enhancements to the authors via our
MAILING LIST (questions, bug reports, suggestions/patches):
log4perl-devel@lists.sourceforge.net
Authors (please contact them via the list above, not directly): Mike
Schilli <m@perlmeister.com>, Kevin Goess <cpan@goess.org>
Contributors (in alphabetical order): Ateeq Altaf, Cory Bennett, Jens
Berthold, Jeremy Bopp, Hutton Davidson, Chris R. Donnelly, Matisse
Enzer, Hugh Esco, Anthony Foiani, James FitzGibbon, Carl Franks, Dennis
Gregorovic, Andy Grundman, Paul Harrington, Alexander Hartmaier David
Hull, Robert Jacobson, Jason Kohles, Jeff Macdonald, Markus Peter,
Brett Rann, Peter Rabbitson, Erik Selberg, Aaron Straup Cope, Lars
Thegler, David Viner, Mac Yang.
perl v5.36.0 2022-10-30 Appender::File(3pm)
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