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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 AT perlmeister.com> and Kevin Goess <cpan AT 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 AT lists.net
Authors (please contact them via the list above, not directly): Mike Schilli
<m AT perlmeister.com>, Kevin Goess <cpan AT 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 v5.32.1 2021-02-14 Appender::File(3pm)
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On Apache
Under GNU General Public License
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