NAME

       Server::Starter - a superdaemon for hot-deploying server programs

SYNOPSIS

         # from command line
         % start_server --port=80 my_httpd

         # in my_httpd
         use Server::Starter qw(server_ports);

         my $listen_sock = IO::Socket::INET->new(
             Proto => 'tcp',
         );
         $listen_sock->fdopen((values %{server_ports()})[0], 'w')
             or die "failed to bind to listening socket:$!";

         while (1) {
             if (my $conn = $listen_sock->accept) {
                 ....
             }
         }

DESCRIPTION

       It is often a pain to write a server program that supports graceful restarts, with no
       resource leaks.  Server::Starter solves the problem by splitting the task into two.  One
       is start_server, a script provided as a part of the module, which works as a superdaemon
       that binds to zero or more TCP ports or unix sockets, and repeatedly spawns the server
       program that actually handles the necessary tasks (for example, responding to incoming
       connections).  The spawned server programs under Server::Starter call accept(2) and handle
       the requests.

       To gracefully restart the server program, send SIGHUP to the superdaemon.  The superdaemon
       spawns a new server program, and if (and only if) it starts up successfully, sends SIGTERM
       to the old server program.

       By using Server::Starter it is much easier to write a hot-deployable server.  Following
       are the only requirements a server program to be run under Server::Starter should conform
       to:

       •   receive file descriptors to listen to through an environment variable

       •   perform a graceful shutdown when receiving SIGTERM

       A Net::Server personality that can be run under Server::Starter exists under the name
       Net::Server::SS::PreFork.

METHODS

       server_ports
           Returns zero or more file descriptors on which the server program should call
           accept(2) in a hashref.  Each element of the hashref is:
           (host:port|port|path_of_unix_socket) => file_descriptor.

       start_server
           Starts the superdaemon.  Used by the "start_server" script.

AUTHOR

       Kazuho Oku

SEE ALSO

       Net::Server::SS::PreFork

LICENSE

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