GearmanClient::addServer

(PECL gearman >= 0.5.0)

GearmanClient::addServer — Ajoute un serveur de tâches au client

Description

public GearmanClient::addServer(string $host = null, int $port = 0, bool $setupExceptionHandler = true): bool

Ajoute un serveur de tâches à une liste de serveurs qui peuvent être utilisés pour accomplir une tâche. Aucune entrée/sortie sur un socket n'est faite ici; le serveur est juste ajouté à la liste.

Liste de paramètres

host: Le nom d'hôte du serveur de travaux.
port: Le port du serveur de travaux.

Valeurs de retour

Cette fonction retourne true en cas de succès ou false si une erreur survient.

Exemples

Exemple #1 Ajout de deux serveurs

<?php

# Crée notre objet client.
$gmclient= new GearmanClient();

# Ajoute deux serveurs de tâches, le premier écoutant sur le port par défaut, 4730
$gmclient->addServer("10.0.0.1"); 
$gmclient->addServer("10.0.0.2", 7003);

?>

Voir aussi

GearmanClient::addServers() - Ajoute une liste de serveurs de tâches au client

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User Contributed Notes 8 notes

down

jqv8gg681 at relay dot firefox dot com ¶

2 years ago

Combining recommendations from brainreflex and iloveapplepie, as well as hours of testing. This avoids some bugs in cross versions of gearman across platforms. 
It steps though the server list and fails if all are inaccessible.
I also use the same override as "class SmartGearmanClient extends GearmanClient" for the clients.

<?php // WORKER
class SmartGearmanWorker extends GearmanWorker
{
    public $server = false;
    public function connect($servers = array( array('host' => '127.0.0.1', 'port' => '4730') ))
    {
        $connected = false;
        foreach ($servers as $server) {
            $c = new GearmanClient();
            $c->addServer($server['host'], $server['port'], false);
    
            if (@$c->ping('ping')) {              
                $this->addServer($server['host'], $server['port']);
                $connected=true;
                $this->server = array(
                   'host'=>$server['host'],
                   'port'=>$server['port']
                );
                break; // Remove this to use last working server in list
            }
        }
        return $connected;
    }
}

echo "Starting\n";

# Add some servers
$servers = array(
    array('host' => '127.0.0.1', 'port' => '4730'),
    array('host' => '127.0.0.1', 'port' => '4731'),
    array('host' => '127.0.0.1', 'port' => '4732'),
    array('host' => '127.0.0.2', 'port' => '4730'),
    array('host' => '192.168.204.10', 'port' => '4730')
);

# Create our worker object.
$gmw= new SmartGearmanWorker();

if ($gmw->connect($servers)) {
    # Register function "reverseString" with the server. 
    $gmw->addFunction("reverseString", "reverseString_fn");

    print "Connected to {$gmw->server['host']}:{$gmw->server['port']}...\n";
    print "Waiting for jobs...\n";

    while ($gmw->work()) {
        if ($gmw->returnCode() != GEARMAN_SUCCESS) {
            echo "return_code: " . $gmw->returnCode() . "\n";
            break;
        }
    }

    echo "DONE\n";
} else {
    echo "Unable to connect to any gearman-job-servers.".PHP_EOL;
};

function reverseString_fn($job)
{
    echo "Received job: " . $job->handle() . "\n";
 
    $workload = $job->workload();
    $workload_size = $job->workloadSize();

    echo "Workload: $workload ($workload_size)\n";

    # Lets send some progress information
    for ($x= 0; $x < $workload_size; $x++) {
        echo "Sending status: " . ($x + 1) . "/$workload_size complete\n";
        $job->sendStatus($x+1, $workload_size);
        $job->sendData(substr($workload, $x, 1));    
        sleep(1);
    }

    $result= strrev($workload);
    echo "Result: $result\n";

    # Return what we want to send back to the client.
    return $result;
}

down

brainreflex at gmail dot com ¶

8 years ago

Amit, kosta250

I found a workaround to avoid the dead servers and continue with rest alive. 

<?php

$servers = array(
  array('host' => '127.0.0.1', 'port' => '4730'), 
  array('host' => '127.0.0.1', 'port' => '4731'), 
  array('host' => '127.0.0.1', 'port' => '4732'), 
  array('host' => '127.0.0.2', 'port' => '4730')
);

$client= new \GearmanClient();

foreach($servers as $server) {
  $c = new \GearmanClient();
  $c->addServer($server['host'], $server['port']);

  if (@$c->ping('ping')) {
    $client->addServer($server['host'], $server['port']);
  }
}

?>

down

Peter ¶

9 years ago

Solution:
https://bugs.launchpad.net/gearmand/+bug/1118751

down

iloveapplepie ¶

2 years ago

Sometimes you want the job server to start even if not all servers are available.  The reason is that if at a later point the server comes back gearman will use it, even if if failed during the add server operation. 

class SmartGearmanWorker extends GearmanWorker
{
    function addServer($host = '127.0.0.1', $port = 4730):bool
    {
        try {
            parent::addServer($host, $port);
            echo "\nSERVER $host WORKED";
        } catch (GearmanException $e) {
            echo "\nSERVER $host FAILED";
        }
        return true;
    }
}

class SmartGearmanClient extends GearmanClient 
{
    function addServer($host = '127.0.0.1', $port = 4730,  bool $setupExceptionHandler = false):bool
    {
        try {
            parent::addServer($host, $port, $setupExceptionHandler);
            echo "\nSERVER $host WORKED";
    } catch (GearmanException $e) {
                
            echo "\nSERVER $host FAILED"; //this does not get called even if the server is down
        }
        return true;
    }
}

down

kosta250 at gmail dot com ¶

8 years ago

Adding to Amit's comments,  I found that if the first server in the list of servers is down, then there seems to be no way to handle such a condition.

down

info at phpgangsta dot de ¶

11 years ago

Since a few versions the port parameter is not optional anymore. I have version 1.1.1 of pecl/gearman compiled with libgearman 1.1.5, and I'm getting the following error:

send_packet(GEARMAN_COULD_NOT_CONNECT) Failed to send server-options packet -> libgearman/connection.cc:430

This happens if you don't provide a port.

Just set the second parameter to 4730 and it is working again.

down

-1

michael at butlerpc dot net ¶

5 years ago

Prior to version 2.0.5, addServer DOES perform socket I/O indirectly because it calls set_server_option internally for an exception handler. This means if the server is unreachable you will get a GearmanException thrown at this point, and you may want to catch and handle it in your application.

<?php

$client->addServer('127.0.0.1', 4321); // does attempt a socket connection!

?>

Starting with version 2.0.5 of the extension, a third boolean argument (after $port) may be passed false in order to prevent this from happening.

<?php

$client->addServer('127.0.0.1', 4321, false); // no socket i/o happens here

?>

down

-1

Amit ¶

11 years ago

The addServer and addServers are unforgiving when any of the addresses are down. I tried using exceptions, but it does not quite work. Can you provide a working example to handle a list of servers where one or more is not running.

Thanks

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