Cre­ate dae­mon child processes with PHP

September 29th, 2009 by Ryan Huff Leave a reply »
/**
 * System_Daemon turns PHP-CLI scripts into daemons.
 *
 * PHP version 5
 *
 * @category  System
 * @package   System_Daemon
 * @author    Kevin 
 * @copyright 2008 Kevin van Zonneveld
 * @license   http://www.opensource.org/licenses/bsd-license.php
 * @version   SVN: Release: $Id: logparser.php 215 2009-04-25 10:10:18Z kevin $
 * @link      http://trac.plutonia.nl/projects/system_daemon
 */

/**
 * System_Daemon Example Code
 *
 * If you run this code successfully, a daemon will be spawned
 * but unless have already generated the init.d script, you have
 * no real way of killing it yet.
 *
 * In this case wait 3 runs, which is the maximum for this example.
 *
 *
 * In panic situations, you can always kill you daemon by typing
 *
 * killall -9 logparser.php
 * OR:
 * killall -9 php
 *
 */

// Allowed arguments & their defaults
$runmode = array(
    "no-daemon" => false,
    "help" => false,
    "write-initd" => false
);

// Scan command line attributes for allowed arguments
foreach ($argv as $k=>$arg) {
    if (substr($arg, 0, 2) == "--" && isset($runmode[substr($arg, 2)])) {
        $runmode[substr($arg, 2)] = true;
    }
}

// Help mode. Shows allowed argumentents and quit directly
if ($runmode["help"] == true) {
    echo "Usage: ".$argv[0]." [runmode]\n";
    echo "Available runmodes:\n";
    foreach ($runmode as $runmod=>$val) {
        echo " --".$runmod."\n";
    }
    die();
}

// Make it possible to test in source directory
// This is for PEAR developers only
ini_set('include_path', ini_get('include_path').':..');

// Include Class
error_reporting(E_ALL);
require_once "System/Daemon.php";

// Setup
$options = array(
    "appName" => "logparser",
    "appDir" => dirname(__FILE__),
    "appDescription" => "Parses vsftpd logfiles and stores them in MySQL",
    "authorName" => "Kevin van Zonneveld",
    "authorEmail" => "kevin@vanzonneveld.net",
    "sysMaxExecutionTime" => "0",
    "sysMaxInputTime" => "0",
    "sysMemoryLimit" => "1024M",
    "appRunAsGID" => 1000,
    "appRunAsUID" => 1000
);

System_Daemon::setOptions($options);

// Overrule the signal handler with any function
System_Daemon::setSigHandler(SIGCONT, array("System_Daemon",
    "defaultSigHandler"));

// This program can also be run in the forground with runmode --no-daemon
if (!$runmode["no-daemon"]) {
    // Spawn Daemon
    System_Daemon::start();
}

// With the runmode --write-initd, this program can automatically write a
// system startup file called: 'init.d'
// This will make sure your daemon will be started on reboot
if (!$runmode["write-initd"]) {
    System_Daemon::log(System_Daemon::LOG_INFO, "not writing ".
        "an init.d script this time");
} else {
    if (($initd_location = System_Daemon::writeAutoRun()) === false) {
        System_Daemon::log(System_Daemon::LOG_NOTICE, "unable to write ".
            "init.d script");
    } else {
        System_Daemon::log(System_Daemon::LOG_INFO, "sucessfully written ".
            "startup script: ".$initd_location);
    }
}

// Run your code
// Here comes your own actual code

// This variable gives your own code the ability to breakdown the daemon:
$runningOkay = true;

// This variable keeps track of how many 'runs' or 'loops' your daemon has
// done so far. For example purposes, we're quitting on 3.
$cnt = 1;

// While checks on 3 things in this case:
// - That the Daemon Class hasn't reported it's dying
// - That your own code has been running Okay
// - That we're not executing more than 3 runs
while (!System_Daemon::isDying() && $runningOkay && $cnt <=3) {
    // What mode are we in?
    $mode = "'".(System_Daemon::isInBackground() ? "" : "non-" ).
        "daemon' mode";

    // Log something using the Daemon class's logging facility
    // Depending on runmode it will either end up:
    //  - In the /var/log/logparser.log
    //  - On screen (in case we're not a daemon yet)
    System_Daemon::log(System_Daemon::LOG_INFO,
        System_Daemon::getOption("appName").
        " running in ".$mode." ".$cnt."/3");

    // In the actuall logparser program, You could replace 'true'
    // With e.g. a  parseLog('vsftpd') function, and have it return
    // either true on success, or false on failure.
    $runningOkay = true;
    //$runningOkay = parseLog('vsftpd');

    // Should your parseLog('vsftpd') return false, then
    // the daemon is automatically shut down.
    // An extra log entry would be nice, we're using level 3,
    // which is critical.
    // Level 4 would be fatal and shuts down the daemon immediately,
    // which in this case is handled by the while condition.
    if (!$runningOkay) {
        System_Daemon::log(System_Daemon::LOG_ERR, "parseLog() ".
            "produced an error, ".
            "so this will be my last run");
    }

    // Relax the system by sleeping for a little bit
    // iterate also clears statcache
    System_Daemon::iterate(2);

    $cnt++;
}

// Shut down the daemon nicely
// This is ignored if the class is actually running in the foreground
System_Daemon::stop();
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