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Abstract out the parallelizing daemon stuff

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Zach Copley 2009-08-06 01:15:08 +00:00
parent 3ebbc1c388
commit 6d29592ec7
1 changed files with 225 additions and 0 deletions
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<?php
/**
* Laconica, the distributed open-source microblogging tool
*
* Base class for making daemons that can do several tasks in parallel.
*
* PHP version 5
*
* LICENCE: This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*
* @category Daemon
* @package Laconica
* @author Zach Copley <zach@controlyourself.ca>
* @author Evan Prodromou <evan@controlyourself.ca>
* @copyright 2009 Control Yourself, Inc.
* @license http://www.fsf.org/licensing/licenses/agpl-3.0.html GNU Affero General Public License version 3.0
* @link http://laconi.ca/
*/
if (!defined('LACONICA')) {
exit(1);
}
declare(ticks = 1);
/**
* Daemon able to spawn multiple child processes to do work in parallel
*
* @category Daemon
* @package Laconica
* @author Zach Copley <zach@controlyourself.ca>
* @author Evan Prodromou <evan@controlyourself.ca>
* @license http://www.fsf.org/licensing/licenses/agpl-3.0.html GNU Affero General Public License version 3.0
* @link http://laconi.ca/
*/
class ParallelizingDaemon extends Daemon
{
private $_children = array();
private $_interval = 0; // seconds
private $_max_children = 0; // maximum number of children
private $_debug = false;
/**
* Constructor
*
* @param string $id the name/id of this daemon
* @param int $interval sleep this long before doing everything again
* @param int $max_children maximum number of child processes at a time
* @param boolean $debug debug output flag
*
* @return void
*
**/
function __construct($id = null, $interval = 60, $max_children = 2,
$debug = null)
{
parent::__construct(true); // daemonize
$this->_interval = $interval;
$this->_max_children = $max_children;
$this->_debug = $debug;
if (isset($id)) {
$this->set_id($id);
}
}
/**
* Run the daemon
*
* @return void
*/
function run()
{
if (isset($this->_debug)) {
echo $this->name() . " - debugging output enabled.\n";
}
do {
$objects = $this->getObjects();
foreach ($objects as $o) {
// Fork a child for each object
$pid = pcntl_fork();
if ($pid == -1) {
die ($this->name() . ' - Couldn\'t fork!');
}
if ($pid) {
// Parent
if (isset($this->_debug)) {
echo $this->name() .
" (parent) forked new child - pid $pid.\n";
}
$this->_children[] = $pid;
} else {
// Child
// Do something with each object
$this->childTask($o);
exit();
}
// Remove child from ps list as it finishes
while (($c = pcntl_wait($status, WNOHANG OR WUNTRACED)) > 0) {
if (isset($this->_debug)) {
echo $this->name() . " child $c finished.\n";
}
$this->removePs($this->_children, $c);
}
// Wait! We have too many damn kids.
if (sizeof($this->_children) >= $this->_max_children) {
if (isset($this->_debug)) {
echo $this->name() . " - Too many children. Waiting...\n";
}
if (($c = pcntl_wait($status, WUNTRACED)) > 0) {
if (isset($this->_debug)) {
echo $this->name() .
" - Finished waiting for child $c.\n";
}
$this->removePs($this->_children, $c);
}
}
}
// Remove all children from the process list before restarting
while (($c = pcntl_wait($status, WUNTRACED)) > 0) {
if (isset($this->_debug)) {
echo $this->name() . " child $c finished.\n";
}
$this->removePs($this->_children, $c);
}
// Rest for a bit
if (isset($this->_debug)) {
echo $this->name() . ' - Waiting ' . $this->_interval .
" secs before running again.\n";
}
if ($this->_interval > 0) {
sleep($this->_interval);
}
} while (true);
}
/**
* Remove a child process from the list of children
*
* @param array &$plist array of processes
* @param int $ps process id
*
* @return void
*/
function removePs(&$plist, $ps)
{
for ($i = 0; $i < sizeof($plist); $i++) {
if ($plist[$i] == $ps) {
unset($plist[$i]);
$plist = array_values($plist);
break;
}
}
}
/**
* Get a list of objects to work on in parallel
*
* @return array An array of objects to work on
*/
function getObjects()
{
die('Implement ParallelizingDaemon::getObjects().');
}
/**
* Do something with each object in parallel
*
* @param mixed $object data to work on
*
* @return void
*/
function childTask($object)
{
die("Implement ParallelizingDaemon::childTask($object).");
}
}