NAME¶

Sys::Syslog - Perl interface to the UNIX syslog(3) calls

VERSION¶

This is the documentation of version 0.36

SYNOPSIS¶

    use Sys::Syslog;                        # all except setlogsock()
    use Sys::Syslog qw(:standard :macros);  # standard functions & macros
    openlog($ident, $logopt, $facility);    # don't forget this
    syslog($priority, $format, @args);
    $oldmask = setlogmask($mask_priority);
    closelog();

DESCRIPTION¶

"Sys::Syslog" is an interface to the UNIX syslog(3) program. Call syslog() with a string priority and a list of printf() args just like syslog(3).

EXPORTS¶

"Sys::Syslog" exports the following "Exporter" tags:

• ":standard" exports the standard syslog(3) functions:

      openlog closelog setlogmask syslog
      

• ":extended" exports the Perl specific functions for syslog(3):

      setlogsock
      

• ":macros" exports the symbols corresponding to most of your syslog(3) macros and the LOG_UPTO() and LOG_MASK() functions. See "CONSTANTS" for the supported constants and their meaning.

By default, "Sys::Syslog" exports the symbols from the ":standard" tag.

FUNCTIONS¶

openlog($ident, $logopt, $facility)

Opens the syslog. $ident is prepended to every message. $logopt contains zero or more of the options detailed below. $facility specifies the part of the system to report about, for example "LOG_USER" or "LOG_LOCAL0": see "Facilities" for a list of well-known facilities, and your syslog(3) documentation for the facilities available in your system. Check "SEE ALSO" for useful links. Facility can be given as a string or a numeric macro.

This function will croak if it can't connect to the syslog daemon.

Note that openlog() now takes three arguments, just like openlog(3).

You should use openlog() before calling syslog().

Options

    openlog($name, "ndelay,pid", "local0");

    openlog($name, "ndelay,pid", LOG_LOCAL0);

syslog($priority, $message)

syslog($priority, $format, @args)

If $priority permits, logs $message or "sprintf($format, @args)" with the addition that %m in $message or $format is replaced with "$!" (the latest error message).

$priority can specify a level, or a level and a facility. Levels and facilities can be given as strings or as macros. When using the "eventlog" mechanism, priorities "DEBUG" and "INFO" are mapped to event type "informational", "NOTICE" and "WARNING" to "warning" and "ERR" to "EMERG" to "error".

If you didn't use openlog() before using syslog(), syslog() will try to guess the $ident by extracting the shortest prefix of $format that ends in a ":".

Examples

    # informational level
    syslog("info", $message);
    syslog(LOG_INFO, $message);
    # information level, Local0 facility
    syslog("info|local0", $message);
    syslog(LOG_INFO|LOG_LOCAL0, $message);
    

setlogmask($mask_priority)

Sets the log mask for the current process to $mask_priority and returns the old mask. If the mask argument is 0, the current log mask is not modified. See "Levels" for the list of available levels. You can use the LOG_UPTO() function to allow all levels up to a given priority (but it only accept the numeric macros as arguments).

Examples

Only log errors:

    setlogmask( LOG_MASK(LOG_ERR) );
    

Log everything except informational messages:

    setlogmask( ~(LOG_MASK(LOG_INFO)) );
    

Log critical messages, errors and warnings:

    setlogmask( LOG_MASK(LOG_CRIT)
              | LOG_MASK(LOG_ERR)
              | LOG_MASK(LOG_WARNING) );
    

Log all messages up to debug:

    setlogmask( LOG_UPTO(LOG_DEBUG) );
    

setlogsock()

Sets the socket type and options to be used for the next call to openlog() or syslog(). Returns true on success, "undef" on failure.

Being Perl-specific, this function has evolved along time. It can currently be called as follow:

    setlogsock("udp");

    setlogsock({ type => "tcp", port => 2486 });

    setlogsock({ type => "tcp", host => $loghost });

    setlogsock(["native", "udp", "unix"]);

closelog()

Closes the log file and returns true on success.

THE RULES OF SYS::SYSLOG¶

The First Rule of Sys::Syslog is: You do not call "setlogsock".

The Second Rule of Sys::Syslog is: You do not call "setlogsock".

The Third Rule of Sys::Syslog is: The program crashes, "die"s, calls "closelog", the log is over.

The Fourth Rule of Sys::Syslog is: One facility, one priority.

The Fifth Rule of Sys::Syslog is: One log at a time.

The Sixth Rule of Sys::Syslog is: No "syslog" before "openlog".

The Seventh Rule of Sys::Syslog is: Logs will go on as long as they have to.

The Eighth, and Final Rule of Sys::Syslog is: If this is your first use of Sys::Syslog, you must read the doc.

EXAMPLES¶

An example:

    openlog($program, 'cons,pid', 'user');
    syslog('info', '%s', 'this is another test');
    syslog('mail|warning', 'this is a better test: %d', time);
    closelog();
    syslog('debug', 'this is the last test');

Another example:

    openlog("$program $$", 'ndelay', 'user');
    syslog('notice', 'fooprogram: this is really done');

Example of use of %m:

    $! = 55;
    syslog('info', 'problem was %m');   # %m == $! in syslog(3)

Log to UDP port on $remotehost instead of logging locally:

    setlogsock("udp", $remotehost);
    openlog($program, 'ndelay', 'user');
    syslog('info', 'something happened over here');

CONSTANTS¶

DIAGNOSTICS¶

"Invalid argument passed to setlogsock"

(F) You gave setlogsock() an invalid value for $sock_type.

"eventlog passed to setlogsock, but no Win32 API available"

(W) You asked setlogsock() to use the Win32 event logger but the operating system running the program isn't Win32 or does not provides Win32 compatible facilities.

"no connection to syslog available"

(F) syslog() failed to connect to the specified socket.

"stream passed to setlogsock, but %s is not writable"

(W) You asked setlogsock() to use a stream socket, but the given path is not writable.

"stream passed to setlogsock, but could not find any device"

(W) You asked setlogsock() to use a stream socket, but didn't provide a path, and "Sys::Syslog" was unable to find an appropriate one.

"tcp passed to setlogsock, but tcp service unavailable"

(W) You asked setlogsock() to use a TCP socket, but the service is not available on the system.

"syslog: expecting argument %s"

(F) You forgot to give syslog() the indicated argument.

"syslog: invalid level/facility: %s"

(F) You specified an invalid level or facility.

"syslog: too many levels given: %s"

(F) You specified too many levels.

"syslog: too many facilities given: %s"

(F) You specified too many facilities.

"syslog: level must be given"

(F) You forgot to specify a level.

"udp passed to setlogsock, but udp service unavailable"

(W) You asked setlogsock() to use a UDP socket, but the service is not available on the system.

"unix passed to setlogsock, but path not available"

(W) You asked setlogsock() to use a UNIX socket, but "Sys::Syslog" was unable to find an appropriate an appropriate device.

HISTORY¶

"Sys::Syslog" is a core module, part of the standard Perl distribution since 1990. At this time, modules as we know them didn't exist, the Perl library was a collection of .pl files, and the one for sending syslog messages with was simply lib/syslog.pl, included with Perl 3.0. It was converted as a module with Perl 5.0, but had a version number only starting with Perl 5.6. Here is a small table with the matching Perl and "Sys::Syslog" versions.

    Sys::Syslog     Perl
    -----------     ----
       undef        5.0.0 ~ 5.5.4
       0.01         5.6.*
       0.03         5.8.0
       0.04         5.8.1, 5.8.2, 5.8.3
       0.05         5.8.4, 5.8.5, 5.8.6
       0.06         5.8.7
       0.13         5.8.8
       0.22         5.10.0
       0.27         5.8.9, 5.10.1 ~ 5.14.*
       0.29         5.16.*
       0.32         5.18.*
       0.33         5.20.*
       0.33         5.22.*

SEE ALSO¶

AUTHORS & ACKNOWLEDGEMENTS¶

Tom Christiansen <tchrist (at) perl.com> and Larry Wall <larry (at) wall.org>.

UNIX domain sockets added by Sean Robinson <robinson_s (at) sc.maricopa.edu> with support from Tim Bunce <Tim.Bunce (at) ig.co.uk> and the "perl5-porters" mailing list.

Dependency on syslog.ph replaced with XS code by Tom Hughes <tom (at) compton.nu>.

Code for constant()s regenerated by Nicholas Clark <nick (at) ccl4.org>.

Failover to different communication modes by Nick Williams <Nick.Williams (at) morganstanley.com>.

Extracted from core distribution for publishing on the CPAN by Sébastien Aperghis-Tramoni <sebastien (at) aperghis.net>.

XS code for using native C functions borrowed from "Unix::Syslog", written by Marcus Harnisch <marcus.harnisch (at) gmx.net>.

Yves Orton suggested and helped for making "Sys::Syslog" use the native event logger under Win32 systems.

Jerry D. Hedden and Reini Urban provided greatly appreciated help to debug and polish "Sys::Syslog" under Cygwin.

BUGS¶

Please report any bugs or feature requests to "bug-sys-syslog (at) rt.cpan.org", or through the web interface at <http://rt.cpan.org/Public/Dist/Display.html?Name=Sys-Syslog>. I will be notified, and then you'll automatically be notified of progress on your bug as I make changes.

SUPPORT¶

You can find documentation for this module with the perldoc command.

    perldoc Sys::Syslog

You can also look for information at:

• Perl Documentation

  <http://perldoc.perl.org/Sys/Syslog.html>

• MetaCPAN

  <https://metacpan.org/module/Sys::Syslog>

• Search CPAN

  <http://search.cpan.org/dist/Sys-Syslog/>

• AnnoCPAN: Annotated CPAN documentation

  <http://annocpan.org/dist/Sys-Syslog>

• CPAN Ratings

  <http://cpanratings.perl.org/d/Sys-Syslog>

• RT: CPAN's request tracker

  <http://rt.cpan.org/Dist/Display.html?Queue=Sys-Syslog>

The source code is available on Git Hub: <https://github.com/maddingue/Sys-Syslog/>

COPYRIGHT¶

Copyright (C) 1990-2012 by Larry Wall and others.

LICENSE¶

This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself.