Log::Log4perl::Appender::File - Log to file
use Log::Log4perl::Appender::File;
my $app = Log::Log4perl::Appender::File->new(
filename => 'file.log',
mode => 'append',
autoflush => 1,
umask => 0222,
);
$file->log(message => "Log me\n");
This is a simple appender for writing to a file.
The log() method takes a single scalar. If a newline character
should terminate the message, it has to be added explicitely.
Upon destruction of the object, the filehandle to access the file is flushed and closed.
If you want to switch over to a different logfile, use the
file_switch($newfile) method which will first close the old
file handle and then open a one to the new file specified.
$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, 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, 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 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.
:utf8 mode:
my $app = Log::Log4perl::Appender::File->new(
filename => 'file.log',
mode => 'append',
utf8 => 1,
);
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).
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 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 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.
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.
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 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.
Mike Schilli <log4perl@perlmeister.com>, 2003, 2005