Net::Server::PreFork(3pm)

NAME

Net::Server::PreFork - Net::Server personality

SYNOPSIS

use Net::Server::PreFork;
@ISA = qw(Net::Server::PreFork);

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

__PACKAGE__->run();

DESCRIPTION

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

This personality binds to one or more ports and then forks
"min_servers" child process. The server will make sure that at any
given time there are "min_spare_servers" available to receive a client request, up to "max_servers". Each of these children will process up
to "max_requests" client connections. This type is good for a heavily hit site, and should scale well for most applications. (Multi port
accept is accomplished 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 and the Net::Server::PreForkSimple parent class, Net::Server::PreFork contains several other configurable parameters. You really should also see Net::Server::PreForkSimple.: Key Value Default
min_servers \d+ 5
min_spare_servers \d+ 2
max_spare_servers \d+ 10
max_servers \d+ 50
max_requests \d+ 1000; serialize (flock|semaphore|pipe) undef
# serialize defaults to flock on multi_port or on Solaris
lock_file "filename" POSIX::tmpnam; check_for_dead \d+ 30
check_for_waiting \d+ 10; max_dequeue \d+ undef
check_for_dequeue \d+ undef; child_communication 1 undef
min_servers: The minimum number of servers to keep running.
min_spare_servers: The minimum number of servers to have waiting for requests. Minimum and maximum numbers should not be set to close to each other or the server will fork and kill children too often.
max_spare_servers: The maximum number of servers to have waiting for requests. See
min_spare_servers.
max_servers: The maximum number of child servers to start. This does not apply to dequeue processes.
check_for_waiting: Seconds to wait before checking to see if we can kill off some
waiting servers.
child_communication: Enable child communication to parent via unix sockets. If set to
true, will let children write to the socket contained in
$self->{server}->{parent_sock}. The parent will be notified
through child_is_talking_hook where the first argument is the
socket to the child. The child's socket is stored in
$self->{server}->{children}->{$child_pid}->{sock}.

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
min_servers 20
max_servers 80
min_spare_servers 10
min_spare_servers 15; 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; ### enable child communication ?
# child_communication; #-------------- file test.conf --------------

PROCESS FLOW

Process flow follows Net::Server until the loop phase. At this point
"min_servers" are forked and wait for connections. When a child
accepts a connection, finishs processing a client, or exits, it relays that information to the parent, which keeps track and makes sure there are enough children to fulfill "min_servers", "min_spare_servers",
"max_spare_servers", and "max_servers".

HOOKS

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

"$self->run_n_children_hook()": This hook occurs at the top of run_n_children which is called each time the server goes to start more child processes. This gives the parent to do a little of its own accountting (as desired). Idea
for this hook came from James FitzGibbon.
"$self->parent_read_hook()": This hook occurs any time that the parent reads information from
the child. The line from the child is sent as an argument.
"$self->child_is_talking_hook()": This hook occurs if child_communication is true and the child has
written to $self->{server}->{parent_sock}. The first argument will be the open socket to the child.

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@seamons.com

THANKS