NAME

       App::Control - Perl module for apachectl style control of another script or executable

SYNOPSIS

           use App::Control;
           my $ctl = App::Control->new(
               EXEC => $exec,
               ARGS => \@args,
               PIDFILE => $pidfile,
               SLEEP => 1,
               VERBOSE => 1,
           );
           my $pid = $ctl->pid;
           if ( $ctl->running )
           {
               print "$pid is running\n";
           }
           else
           {
               print "$pid is not running\n";
           }
           # or alternatively ...
           print $ctl->status;
           $ctl->start;
           # or alternatively ...
           $ctl->cmd( 'start' );
           $ctl->stop;
           $ctl->hup;
           $ctl->restart;

DESCRIPTION

       App::Control is a simple module to replicate the kind of functionality you get with
       apachectl to control apache, but for any script or executable. There is a very simple OO
       interface, where the constructor is used to specify the executable, command line
       arguments, and pidfile, and various methods (start, stop, etc.) are used to control the
       executable in the obvious way.

       The module is intended to be used in a simple wrapper control script. Currently the module
       does a fork and exec to start the executable, and sets the signal handler for SIGCHLD to
       'IGNORE' to avoid zombie processes.

CONSTRUCTOR

       The constructor is called with a hash of options in the standard way. The options are as
       follows:

   EXEC
       Path to the executable to be controlled. This option is REQUIRED.

   ARGS
       Command line arguments for the executable. This option is OPTIONAL, but if set, should be
       an ARRAY reference.

   PIDFILE
       Path to the pidfile for the executable. This need not exists, but the constructor will die
       if it thinks it can't create it. If the path where the pidfile lives doesn't exist the
       constructor will try to create it. This option is REQUIRED.

   IGNOREFILE
       The ignore file allows you to temporarily disable the control functionality.  Suppose you
       have a chkdaemon / crontab entry that restarts a service; specifying an IGNOREFILE means
       that you can disable this wihtout having to edit the relevant config files.

   CREATE_PIDFILE
       By default, App::Control depends on the application to manage the pid file.  This is
       consistent will analogous utilities (apachectl, chkdaemon, etc.), but if you would like
       App::Control to create and remove pid files for you, then set this option to a true value.

   SLEEP
       Number of seconds to sleep before checking that the process has been started.  If the
       start fails, the control script will loop with a SLEEP delay per iteration until it has
       (see <"LOOP">). Default is 1 second.

       head2 LOOP

       Number of times to loop before giving up on starting the process.

   VERBOSE
       If set to a true value, the module will output verbose messages to STDERR.

METHODS

   start
       Start the executable specified in the constructor. This method waits until it is convinced
       that the executable has started. It then writes the new pid to the pidfile.

   stop
       Stop the executable specified in the constructor. It assumes that the pid listed in the
       pidfile specified in the constructor is the process to kill.  This method waits until it
       is convinced that the executable has stopped.

   hup
       Send a SIGHUP to the executable.

   restart
       Basically; stop if running, and then start.

   status
       Returns a status message along the lines of "$exec ($pid) is / is not running".

   cmd
       All of the above methods can also be invoked using cmd; i.e.:

           $ctl->start;

       is equivilent to:

           $ctl->cmd( 'start' );

       give or take a call to AUTOLOAD!

   pid
       Returns the current value of the pid in the pidfile.

   running
       returns true if the pid in the pidfile is running.

AUTHOR

       Ave Wrigley <Ave.Wrigley@itn.co.uk>

COPYRIGHT

       Copyright (c) 2001 Ave Wrigley. All rights reserved. This program is free software; you
       can redistribute it and/or modify it under the same terms as Perl itself.