NAME

       Paranoid::Log - Log Functions

VERSION

       $Id: lib/Paranoid/Log.pm, 2.05 2017/02/06 01:48:57 acorliss Exp $

SYNOPSIS

         use Paranoid::Log;

         $rv = startLogger($name, $mechanism, PL_WARN, PL_GE, { %options });
         $rv = stopLogger($name);

         $rv = plog($severity, $message);

DESCRIPTION

       Paranoid::Log provides a logging and message distribution framework that's modeled heavily
       on syslog.  It follows syslog in that it allows one to log messages at various levels of
       severity and have those messages distributed across multiple log mechanisms automatically.
       Within the Paranoid distribution itself it supports logging to files, STDERR, and named
       buffers.  Additional modules exist on CPAN to allow for distribution to e-mail, syslog,
       and more.  It is also relatively trivial to write your own log mechanism to work with this
       framework.

LOGGING MECHANISMS

       Each logging mechanism is implemented as separate module consisting of non-exported
       functions that conform to a a consistent API.  Each mechanism module must have the
       following functions:

         Function        Description
         ------------------------------------------------------
         init            Called when module first loaded
         addLogger       Add a named instance of the mechanism
         delLogger       Removes a named instance of the mechanism
         logMsg          Logs the passed message

       The init function is only called once -- the first time the module is used and accessed.
       No arguments are passed, and if unnecessary for a particular mechanism it can simply
       return a boolean true.

       The logMsg function is used to actually pass a log message to the mechanism.  It is called
       with a record hash based on the following template:

               my %record  = (
                   name      => $name,
                   mechanism => $name,
                   msgtime   => time,
                   severity  => $level,
                   scope     => $scope,
                   message   => $message,
                   options   => {},
                   );

       The options key will be a hash reference to any logger-specific options, should the
       mechanism require one.

       The addLogger function is called whenever a logger is started.  It is called with the
       logger record above, minus a message and msgtime.

       The delLogger function is called whenevever a logger is stopped.  It is called with the
       logger record above, minus a message and msgtime.

       Please see the source for Paranoid::Logger::File for a simple example of a mechanism
       module.

SUBROUTINES/METHODS

   startLogger
         $rv = startLogger($name, $mechanism, PL_WARN, PL_GE, { %options });

       This function enables the specified logging mechanism at the specified levels.  Each
       mechanism (or permutation of) is associated with an arbitrary name.  This name can be used
       to bypass log distribution and log only in the named mechanism.

       If you have your own custom mechanism that complies with the Paranoid::Log calling
       conventions you can pass this the name of the module (for example, MyLog::Foo).

       Log levels are modeled after syslog:

         log level       description
         =====================================================
         PL_EMERG        system is unusable
         PL_ALERT        action must be taken immediately
         PL_CRIT         critical conditions
         PL_ERR          error conditions
         PL_WARN         warning conditions
         PL_NOTICE       normal but significant conditions
         PL_INFO         informational
         PL_DEBUG        debug-level messages

       If omitted level defaults to PL_NOTICE.

       Scope is defined with the following characters:

         character       definition
         =====================================================
         PL_EQ           log only messages at this severity
         PL_GE           log only messages at this severity
                           or higher
         PL_LE           log only messages at this severity
                           or lower
         PL_NE          log at all levels but this severity

       If omitted scope defaults to PL_GE.

       Only the first two arguments are mandatory.  What you put into the %options, and whether
       you need it at all, will depend on the mechanism you're using.  The facilities provided
       directly by Paranoid are as follows:

         mechanism        arguments
         =====================================================
         Stderr          none
         Buffer          bufferSize (optional)
         File            file, mode (optional), perm (optional),
                         syslog (optional)

   stopLogger
         $rv = stopLogger($name);

       Removes the specified logging mechanism from the configuration and re-initializes the
       distribution processor.

   plog
         $rv = plog($severity, $message);

       This call logs the passed message to all facilities enabled at the specified log level.

DEPENDENCIES

       o   Paranoid::Debug

       o   Paranoid::Input

       o   Paranoid::Module

EXAMPLES

       The following example provides the following behavior:  debug messages go to a file,
       notice & above messages go to syslog, and critical and higher messages also go to console
       and e-mail.

         # Set up the logging facilities
         startLogger("debug-log", "File", PL_DEBUG, PL_GE,
           { file => '/var/log/myapp-debug.log' });
         startLogger("console-err", "Stderr", PL_CRIT, PL_GE);

         # This goes only to the debug log
         plog(PL_DEBUG, "Starting application");

         # Again, only the debug log
         plog(PL_NOTICE, "Uh, something happened...");

         # This goes to STDERR and the debug log
         plog(PL_EMERG, "Ack! <choke... silence>");

SEE ALSO

       o   Paranoid::Log::Buffer

       o   Paranoid::Log::File

BUGS AND LIMITATIONS

AUTHOR

       Arthur Corliss (corliss@digitalmages.com)

LICENSE AND COPYRIGHT

       This software is licensed under the same terms as Perl, itself.  Please see
       http://dev.perl.org/licenses/ for more information.

       (c) 2005 - 2017, Arthur Corliss (corliss@digitalmages.com)