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.