Anyone know if JApplicationDaemon works? Topic is solved

[david0058]

I'm assuming it probably does, but I can't find any information on how to use it.

From reading the source code it's not a million miles from JApplicationCli, which works perfectly, but there must be some secret sauce to be applied to get it working.

Here's my simple test programme:

Code: Select all

<?php

const _JEXEC = 1;

if (file_exists(dirname(__DIR__) . '../../defines.php'))
    require_once dirname(__DIR__) . '../../defines.php';

if (!defined('_JDEFINES'))
{
    define('JPATH_BASE', dirname(__DIR__) . "/../..");
    require_once JPATH_BASE . '/includes/defines.php';
}

require_once JPATH_LIBRARIES . '/import.legacy.php';
require_once JPATH_LIBRARIES . '/cms.php';

class LaunchCLI extends JApplicationCli
{
    public function doExecute()
    {   
        $db = JFactory::getDbo();
        $query = $db->getQuery(true);
        $query->select('COUNT(*) AS count')->from($db->quoteName('#__content'));
        $db->setQuery($query);
        $result = $db->loadObject();
        $this->out("pages: " . $result->count);
    }
}

class LaunchDaemon extends JApplicationDaemon
{
    public $name='test';

    public function doExecute()
    {   
        $db = JFactory::getDbo();
        $query = $db->getQuery(true);
        $query->select('COUNT(*) AS count')->from($db->quoteName('#__content'));
        $db->setQuery($query);
        $result = $db->loadObject();
        $this->out("pages: " . $result->count);
    }
}

$options = getopt("d");

try {
    if (array_key_exists('d', $options))
        JApplicationDaemon::getInstance('LaunchDaemon')->execute();
    else
        JApplicationCli::getInstance('LaunchCLI')->execute();
}
catch (Exception $e){
    echo $e->getMessage() . "\n";
}

?>

The JApplicationCli invocation works fine:

Code: Select all

$ php test.php
pages: 1
$ 

but the JApplicationDaemon one isn't working:

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$ php test.php -d
PHP Warning:  pcntl_signal(): Specified handler "DaemonApplication::signal" is not callable (class 'DaemonApplication' not found) in /var/www/game.conlucra.com/public_html/libraries/src/Application/DaemonApplication.php on line 886

Running Joomla 3.10.11

Any ideas gratefully received

David

[david0058]

Just in case it's any help ...

The "missing class" warning is generated in the pcntlSignal() method of the DaemonApplication class in JPATH_BASE/libraries/src/Application/DaemonApplication.php.

So essentially the attempt to attach the static function DaemonApplication::signal() as the signal handler for any signal fails, because it can't find it's own parent class I don't even understand how this can be ...

However, this is the most important function for my application - I want to send the daemon SIGUSR1 and SIGUSR2 to get it to invoke the corresponding signal handlers in my own daemon class.

Code: Select all

<?php
namespace Joomla\CMS\Application;

[snip]

use Joomla\Registry\Registry;

/**
 * Class to turn CliApplication applications into daemons.  It requires CLI and PCNTL support built into PHP.
 *
 * @link   https://www.php.net/manual/en/book.pcntl.php
 * @link   https://www.php.net/manual/en/features.commandline.php
 * @since  1.7.0
 */
class DaemonApplication extends CliApplication
{

[snip]

    /**
     * Method to attach the DaemonApplication signal handler to the known signals.  Applications
     * can override these handlers by using the pcntl_signal() function and attaching a different
     * callback method.
     *
     * @return  boolean
     *
     * @since   1.7.0
     * @see     pcntl_signal()
     */
    protected function setupSignalHandlers()
    {   
        // We add the error suppression for the loop because on some platforms some constants are not defined.
        foreach (self::$signals as $signal)
        {   
            // Ignore signals that are not defined.
            if (!defined($signal) || !is_int(constant($signal)) || (constant($signal) === 0))
            {   
                // Define the signal to avoid notices.
                \JLog::add('Signal "' . $signal . '" not defined. Defining it as null.', \JLog::DEBUG);
                define($signal, null);

                // Don't listen for signal.
                continue;
            }

            // Attach the signal handler for the signal.
            if (!$this->pcntlSignal(constant($signal), array('DaemonApplication', 'signal')))
            {   
                \JLog::add(sprintf('Unable to reroute signal handler: %s', $signal), \JLog::EMERGENCY);

                return false;
            }
        }

        return true;
    }

[snip]

    /**
     * Method to install a signal handler.
     *
     * @param   integer   $signal   The signal number.
     * @param   callable  $handler  The signal handler which may be the name of a user created function,
     *                              or method, or either of the two global constants SIG_IGN or SIG_DFL.
     * @param   boolean   $restart  Specifies whether system call restarting should be used when this
     *                              signal arrives.
     *
     * @return  boolean  True on success.
     *
     * @see     pcntl_signal()
     * @since   1.7.3
     */
    protected function pcntlSignal($signal, $handler, $restart = true)
    {   
        return pcntl_signal($signal, $handler, $restart);    <<<<<<<<<< FAIL
    }

[snip]

}

[david0058]

Appears to be a bug, and also in J4.0.

"DemonApplication sets incorrect class as signal handler." https://issues.joomla.org/tracker/joomla-cms/39533

Maybe there'll be a fix in some future version.

David

[pe7er]

Thanks for your follow-up with reference to the issue!