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Net::Server::PreFork(3pm) User Contributed Perl Documentation Net::Server::PreFork(3pm)
NAME
Net::Server::PreFork - Net::Server personality
SYNOPSIS
use base 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|none) undef
# serialize defaults to flock on multi_port or on Solaris
lock_file "filename" File::Temp->new
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.
check_for_spawn
Seconds between checking to see if we need to spawn more children
min_child_ttl
Minimum number of seconds between starting children and killing a child process
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'}.
serialize
See the documentation under Net::Server::PreForkSimple.
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, finishes 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.
"$self->run_n_children_hook()"
This hook occurs at the top of run_n_children which is called each time the server
goes to start more child processes. This gives the parent to do a little of its own
accounting (as desired). Idea for this hook came from James FitzGibbon.
"$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
$self->{'server'}->{'parent_sock'}. The first argument will be the open socket to the
child.
"$self->idle_loop_hook()"
This hook is called in every pass through the main process wait loop, every
"check_for_waiting" seconds. The first argument is a reference to an array of file
descriptors that can be read at the moment.
"$self->cleanup_dead_child_hook( $child )"
This hook is called when a dead child is detected. A child is considered dead when
the pid does no longer exist. This hook could be used to cleanup possible temporary
files or locks left over by a dead child.
HOT DEPLOY
Since version 2.000, the PreFork server has accepted the TTIN and TTOU signals. When a
TTIN is received, the min and max_servers are increased by 1. If a TTOU signal is
received the min max_servers are 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::PreForkSimple,
Net::Server::MultiType, Net::Server::Single Net::Server::SIG Net::Server::Daemonize
Net::Server::Proto
perl v5.30.0 2020-04-03 Net::Server::PreFork(3pm)
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On Apache
Under GNU General Public License
2024-12-12 17:00 @3.144.250.229 CrawledBy Mozilla/5.0 AppleWebKit/537.36 (KHTML, like Gecko; compatible; ClaudeBot/1.0; +claudebot@anthropic.com)