NAME
    Daemon::Generic - framework to provide start/stop/reload for a daemon

SYNOPSIS
    use Daemon::Generic;

    sub gd_run { ... stuff }

    newdaemon();

DESCRIPTION
   Daemon::Generic provides a framework for starting, stopping,
   reconfiguring daemon-like programs. The framework provides for standard
   commands that work for as init.d files and as apachectl-like commands.

   Programs that use Daemon::Generic subclass Daemon::Generic to override
   its behavior. Almost everything that Genric::Daemon does can be
   overridden as needed.

EXAMPLE USAGE OUTPUT
   Unless overridden, the usage output for your program will look something
   like this:

    Usage: $progname [ -c file ] [ -f ] { start | stop | reload | restart | help | version | check }
     -c            Specify configuration file (defaults to $configfile)
     -f            Run in the foreground (don't detach)
     start         Starts a new $progname if there isn't one running already
     stop          Stops a running $progname
     reload        Causes a running $progname to reload it's config file.  Starts
                   a new one if none is running.
     restart       Stops a running $progname if one is running.  Starts a new one.
     check         Check the configuration file and report the daemon state
     help          Display this usage info
     version       Display the version of $progname

CONSTRUCTION
   To hand control over to "Daemon::Generic", call "newdaemon()". Control
   will be handed back through method calls to functions you define.

   Your @ISA will be modified to include "Daemon::Generic" if if it isn't
   already there.

   These are the arguments to "newdaemon()". Defaults are in (parenthesis).

   progname       ($0) The name of this program. This will be used for
                  logging and for naming the PID file.

   configfile     ("/etc/$progname.conf") The location of the configuration
                  file for this daemon.

   pidbase        (/var/run/$progname) We include the configuration file
                  name as part of the pid file in case there are multiple
                  instances of this daemon. The pidbase is the part of the
                  PID file that does not include the configuration file
                  name.

   pidfile        ("$pidbase.$configfile.pid") The location of the process
                  id file.

   foreground     (0) Do not detach/daemon and run in the foreground
                  instead.

   debug          (0) Turn on debugging.

   no_srand       (0) Normall srand() is called. If no_srand is set then
                  srand() won't be called.

   options        () Additional arguments for Getopt::Long::GetOptions
                  which is used to parse @ARGV. Alternatively: define
                  "&gd_more_opt()".

   minimum_args   (1) Minimum number of @ARGV arguments after flags have
                  been processed.

   maximum_args   (1) Maximum number of @ARGV arguments after flags have
                  been processed.

   version        ($pkg::VERSION) The version number of the daemon.

   logpriority    Used for "logger -p".

MUST-OVERRIDE CALLBACK METHODS
   The package that subclasses Daemon::Generic must provide the following
   callback methods.

   gd_run()       This is where you put your main program.

                  It is okay to change userid/group as the first action of
                  gd_run().

MAY-OVERRIDE CALLBACK METHODS
   The package that subclasses Daemon::Generic does not have to override
   these methods but it may want to.

   gd_preconfig() "gd_preconfig()" is called to parse the configuration
                  file ("$self->{configfile}"). Preconfig is called on all
                  invocations of the daemon ("daemon reload", "daemon
                  check", "daemon stop", etc). It shouldn't start anything
                  but it can and should verify that the config file is
                  fine.

                  The return value should be a hash. With one exception,
                  the return value is only used by "gd_postconfig()". The
                  exception is that "gd_preconfig()" may return a revised
                  PID file location (key "pidfile").

                  Most uses of Daemon::Generic should define
                  "gd_preconfig".

   gd_postconfig(%config)
                  Postconfig() is called only when the daemon is actually
                  starting up. (Or on reconfigs). It is passed the return
                  value from "gd_preconfig".

   gd_setup_signals()
                  Set things up so that SIGHUP calls gd_reconfig_event()
                  and SIGINT calls gd_quit_event(). It will call these at
                  any time so if you want to delay signal delivery or
                  something you should override this method.

   gd_getopt()    This is invoked to parse the command line. Useful things
                  to modify are:

                  $self->{configfile} The location of the configuration
                                      file to be parsed by
                                      "gd_preconfig()".

                  $self->{foreground} Run in the foreground (don't
                                      daemonize).

                  $self->{debug}      Use it yourself.

                  The supplied "gd_getopt()" method uses Getopt::Long.

   gd_parse_argv()
                  Parse any additional command line arguments beyond what
                  "gd_getopt()" handled.

                  $ARGV[0] needs to be left alone if it is one of the
                  following standard items:

                  start     Start up a new daemon.

                  stop      Stop the running daemon.

                  restart   Stop the running daemon, start a new one.

                  reload    Send a signal to the running daemon, asking it
                            to reconfigure itself.

                  check     Just check the configuration file.

                  help      Print the help screen (probably usage()).

                  version   Display the daemon's version.

                  There is no default "gd_parse_argv()".

   gd_check($pidfile, $pid)
                  Normal behavior: return. Define additional checks to run
                  when the "check" command is given. A $pid will only be
                  supplied if there is a daemon running.

   gd_version()   Normal behavior: display a version message and exit.

   gd_help()      Normal behavior: call "gd_usage()".

   gd_commands_more()
                  Used by "gd_usage()": provide information on additional
                  commands beyond "start", "stop", "reload", etc. Return is
                  an array of key value pairs.

                   sub gd_commands_more
                   {
                          return (
                                  savestate => 'Tell xyz server to save its state',
                                  reset     => 'Tell xyz servr to reset',
                          );
                   }

   gd_flags_more  Like "gd_commands_more()" but defines additional command
                  line flags. There should also be a "gd_more_opt()" or an
                  "options" argument to "new()".

   gd_positional_more
                  Like "gd_commands_more()" but defines positional
                  arguments.

   gd_usage()     Display a usage message. The return value from
                  "gd_usage()" is the exit code for the program.

   gd_more_opt()  () Additional arguments for Getopt::Long::GetOptions
                  which is used to parse @ARGV. Alternatively: pass
                  "options" to "new()".

   gd_pidfile()   Figure out the PID file should be.

   gd_error()     Print out an error (call die?)

   gd_other_cmd() Called $ARGV[0] isn't one of the commands that
                  Daemon::Generic knows by default. Default behavior: call
                  "gd_usage()" and exit(1).

   gd_daemonize() Normal behavior: "fork()", "fork()", detach from tty.

   gd_redirect_output()
                  This is a mis-named method. Sorry. This directs
                  "STDOUT"/"STDERR"/"STDIN" to "/dev/null" as part of
                  daemonizing. Used by "gd_daemonize()".

   gd_reopen_output()
                  After daemonizing, output file descriptors are be
                  re-established. Normal behavior: redirect "STDOUT" and
                  "STDERR" to "logger -t $progname[$$]". Used by
                  "gd_daemonize()".

   gd_logname()   Normal behavior: $progname[$$]. Used by
                  "gd_redirect_output()".

   gd_reconfig_event()
                  Normal behavior: call "gd_postconfig(gd_preconfig))".
                  Only referenced by "gd_setup_signals()".

   gd_quit_event()
                  Normal behavior: exit. Only referenced by
                  "gd_setup_signals()".

   gd_kill_groups()
                  Return true if gd_kill should kill process groups ($pid)
                  instead of just the one daemon ($pid). Default is false.

   gd_kill($pid)  Used by the "stop" and "restart" commands to get rid of
                  the old daemon. Normal behavior: send a SIGINT. Check to
                  see if process $pid has died. If it has not, keep
                  checking and if it's still alive. After
                  $Daemon::Generic::force_quit_delay seconds, send a
                  SIGTERM. Keep checking. After another
                  $Daemon::Generic::force_quit_delay seconds, send a
                  SIGKILL (-9). Keep checking. After
                  "$Daemon::Generic::force_quit_delay * 4" seconds or 60
                  seconds (whichever is smaller), give up and exit(1).

   gd_install     Installs the daemon so that it runs automatically at next
                  reboot. Currently done with a symlink to $0 and
                  "/usr/sbin/update-rc.d". Please send patches for other
                  methods!

   gd_can_install Returns a function to do an "gd_install" if installation
                  is possible. Returns 0 otherwise.

   gd_install_pre($method)
                  Normal behavior: return. Called just before doing an
                  installation. The method indicates the installation
                  method (currently always "update-rc.d".)

   gd_install_post($method)
                  Normal behavior: return. Called just after doing an
                  installation.

   gd_uninstall   Will remove the daemon from the automatic startup regime.

   gd_can_uninstall
                  Returns a function to do the work for "gd_uninstall" if
                  it's possible. 0 otherwise.

   gd_uninstall_pre($method)
                  Normal behavior: return. Called just before doing an
                  un-installation. The method indicates the installation
                  method (currently always "update-rc.d".)

   gd_install_post($method)
                  Normal behavior: return. Called just after doing an
                  un-installation.

MEMBER DATA
   Since you need to subclass Daemon::Generic, you need to know what the
   internal data structures for Daemon::Generic are. With two exceptions,
   all of the member data items begin with the prefix "gd_".

   configfile     The location of the configuration file. (Not used by
                  Daemon::Generic).

   debug          Display debugging? (Not used by Daemon::Generic)

   gd_args        The original %args passed to "new".

   gd_progname    The process name. (defaults to $0)

   gd_pidfile     The location of the process ID file.

   gd_logpriority Used for "logger -p".

   gd_foreground  Are we running in the foreground?

EXAMPLE PROGRAM
    my $sleeptime = 1;

    newdaemon(
           progname        => 'ticktockd',
           pidfile         => '/var/run/ticktockd.pid',
           configfile      => '/etc/ticktockd.conf',
    );

    sub gd_preconfig
    {
           my ($self) = @_;
           open(CONFIG, "<$self->{configfile}") or die;
           while(<CONFIG>) {
                   $sleeptime = $1 if /^sleeptime\s+(\d+)/;
           }
           close(CONFIG);
           return ();
    }

    sub gd_run
    {
           while(1) {
                   sleep($sleeptime);
                   print scalar(localtime(time))."\n";
           }
    }

SEE ALSO
   With a while(1) and delayed signal delivery: Daemon::Generic::While1.

   With Event: Daemon::Generic::Event.

   With AnyEvent: Daemon::Generic::AnyEvent.

   Modules that use Daemon::Generic: SyslogScan::Daemon; IO::Event
   (rinetd.pl)

   Other modules that do similar things: Net::Daemon, Net::Server,
   Net::Server::Daemonize, NetServer::Generic, Proc::Application::Daemon,
   Proc::Daemon, Proc::Forking.

LICENSE
   Copyright (C) 2006-2010 David Muir Sharnoff <[email protected]>.
   Copyright (C) 2011 Google, Inc. This module may be used and distributed
   on the same terms as Perl itself.

PACKAGERS
   Daemon::Generic is packaged for Fedora by Emmanuel Seyman
   <[email protected]>.

You are viewing proxied material from ftp.icm.edu.pl. The copyright of proxied material belongs to its original authors. Any comments or complaints in relation to proxied material should be directed to the original authors of the content concerned. Please see the disclaimer for more details.