Net::Server::PreFork(3) User Contributed Perl Documentation 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::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).
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 -------------PROCESS
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.
"$self->parent_read_hook()"
This hook occurs any time that the parent reads information from the child. The line from the
child is sent as an argument.
"$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.
TO DO
See Net::Server
AUTHOR
Paul T. Seamons paul@seamons.com
THANKS
See Net::Server
SEE ALSO
Please see also Net::Server::Fork, Net::Server::INET, Net::Server::PreForkSimple,
Net::Server::MultiType, Net::Server::Single Net::Server::SIG Net::Server::Daemonize
Net::Server::Proto
perl v5.8.8 2004-02-14 Net::Server::PreFork(3)
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