phpman > perldoc > Net::Server::PreForkSimple(3pm)

NAME
    Net::Server::PreForkSimple - Net::Server personality

SYNOPSIS
        use base qw(Net::Server::PreForkSimple);

        sub process_request {
            #...code...
        }

        __PACKAGE__->run();

DESCRIPTION
    Please read the pod on Net::Server first. This module is a personality, or extension, or sub
    class, of the Net::Server module.

    This personality binds to one or more ports and then forks "max_servers" child processes. The
    server will make sure that at any given time there are always "max_servers" available to receive
    a client request. Each of these children will process up to "max_requests" client connections.
    This type is good for a heavily hit site that can keep "max_servers" processes dedicated to the
    serving. (Multi port accept defaults to using flock to serialize the children).

    At this time, it does not appear that this module will pass tests on Win32 systems. Any ideas or
    patches for making the tests pass would be welcome.

SAMPLE CODE
    Please see the sample listed in Net::Server.

COMMAND LINE ARGUMENTS
    In addition to the command line arguments of the Net::Server base class, Net::Server::PreFork
    contains several other configurable parameters.

        Key               Value                   Default
        max_servers       \d+                     50
        max_requests      \d+                     1000

        serialize         (flock|semaphore
                           |pipe|none)  undef
        # serialize defaults to flock on multi_port or on Solaris
        lock_file         "filename"              File::Temp->new

        check_for_dead    \d+                     30

        max_dequeue       \d+                     undef
        check_for_dequeue \d+                     undef

    max_servers
        The maximum number of child servers to start and maintain. This does not apply to dequeue
        processes.

    max_requests
        The number of client connections to receive before a child terminates.

    serialize
        Determines whether the server serializes child connections. Options are undef, flock,
        semaphore, pipe, or none. Default is undef. On multi_port servers or on servers running on
        Solaris, the default is flock. The flock option uses blocking exclusive flock on the file
        specified in *lock_file* (see below). The semaphore option uses IPC::Semaphore (thanks to
        Bennett Todd) for giving some sample code. The pipe option reads on a pipe to choose the
        next. the flock option should be the most bulletproof while the pipe option should be the
        most portable. (Flock is able to relinquish the block if the process dies between accept on
        the socket and reading of the client connection - semaphore and pipe do not). An option of
        none will not perform any serialization. If "none" is passed and there are multiple ports
        then a the default serialization will be used instead of "none."

    lock_file
        Filename to use in flock serialized accept in order to serialize the accept sequence between
        the children. This will default to a generated temporary filename. If default value is used
        the lock_file will be removed when the server closes.

    check_for_dead
        Seconds to wait before checking to see if a child died without letting the parent know.

    max_dequeue
        The maximum number of dequeue processes to start. If a value of zero or undef is given, no
        dequeue processes will be started. The number of running dequeue processes will be checked
        by the check_for_dead variable.

    check_for_dequeue
        Seconds to wait before forking off a dequeue process. The run_dequeue hook must be defined
        when using this setting. It is intended to use the dequeue process to take care of items
        such as mail queues. If a value of undef is given, no dequeue processes will be started.

CONFIGURATION FILE
    "Net::Server::PreFork" allows for the use of a configuration file to read in server parameters.
    The format of this conf file is simple key value pairs. Comments and white space are ignored.

        #-------------- file test.conf --------------

        ### server information
        max_servers   80

        max_requests  1000

        ### user and group to become
        user        somebody
        group       everybody

        ### logging ?
        log_file    /var/log/server.log
        log_level   3
        pid_file    /tmp/server.pid

        ### access control
        allow       .+\.(net|com)
        allow       domain\.com
        deny        a.+

        ### background the process?
        background  1

        ### ports to bind
        host        127.0.0.1
        port        localhost:20204
        port        20205

        ### reverse lookups ?
        # reverse_lookups on

        #-------------- file test.conf --------------

PROCESS FLOW
    Process flow follows Net::Server until the loop phase. At this point "max_servers" are forked
    and wait for connections. When a child accepts a connection, finishes processing a client, or
    exits, it relays that information to the parent, which keeps track and makes sure there are
    always "max_servers" running.

HOOKS
    The PreForkSimple server has the following hooks in addition to the hooks provided by the
    Net::Server base class. See Net::Server

    "$self->run_n_children_hook()"
        This hook occurs at the top of run_n_children which is called each time the server goes to
        start more child processes. This gives the parent to do a little of its own accounting (as
        desired). Idea for this hook came from James FitzGibbon.

    "$self->child_init_hook()"
        This hook takes place immediately after the child process forks from the parent and before
        the child begins accepting connections. It is intended for any additional chrooting or other
        security measures. It is suggested that all perl modules be used by this point, so that the
        most shared memory possible is used.

    "$self->child_finish_hook()"
        This hook takes place immediately before the child tells the parent that it is exiting. It
        is intended for saving out logged information or other general cleanup.

    "$self->run_dequeue()"
        This hook only gets called in conjunction with the check_for_dequeue setting.

    "$self->idle_loop_hook()"
        This hook is called in every pass through the main process wait loop.

HOT DEPLOY
    Since version 2.000, the PreForkSimple server has accepted the TTIN and TTOU signals. When a
    TTIN is received, the max_servers is increased by 1. If a TTOU signal is received the
    max_servers is decreased by 1. This allows for adjusting the number of handling processes
    without having to restart the server.

BUGS
    Tests don't seem to work on Win32. Any ideas or patches would be welcome.

TO DO
    See Net::Server

AUTHOR
    Paul T. Seamons paul AT seamons.com

THANKS
    See Net::Server

SEE ALSO
    Please see also Net::Server::Fork, Net::Server::INET, Net::Server::PreFork,
    Net::Server::MultiType, Net::Server::Single Net::Server::SIG Net::Server::Daemonize
    Net::Server::Proto