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,
);
$file->log(message => "Log me\n");
DESCRIPTION¶
This is a simple appender for writing to a file.
The "log()" method takes a single scalar. If a newline character
should terminate the message, it has to be added explicitely.
Upon destruction of the object, the filehandle to access the file is flushed and
closed.
If you want to switch over to a different logfile, use the
"file_switch($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 syncronisation 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 0222
(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.
- 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.
- 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.
Design and implementation of this module has been greatly inspired by Dave
Rolsky's "Log::Dispatch" appender framework.
COPYRIGHT AND LICENSE¶
Copyright 2002-2009 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.