net::server::prefork(3)

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::Pre
ForkSimple first. This module is a personality, or exten
sion, 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 appli
cations. (Multi port accept is accomplished using flock
to serialize the children).

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 + 5
min_spare_servers + 2
max_spare_servers + 10
max_servers + 50
max_requests + 1000; serialize (flock|semaphore|pipe) undef
# serialize defaults to flock on multi_port or on So; laris
lock_file "filename" POSIX::tmp; nam; check_for_dead + 30
check_for_waiting + 10; max_dequeue + undef
check_for_dequeue + 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 par
ent 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 configura tion 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 connec
tions. When a child accepts a connection, finishs pro
cessing 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.

"$self->parent_read_hook()": This hook occurs any time that the parent reads infor
mation from the child. The line from the child is
sent as an argument.
"$self->child_is_talking_hook()": This hook occurs if child_communication is true and
the child has written to $self->{server}->{par
ent_sock}. The first argument will be the open socket
to the child.

TO DO

See Net::Server

AUTHOR

Paul T. Seamons paul@seamons.com

THANKS