Gearman

Gearman is a distributed job queue system that allows you to distribute work to multiple machines or processes. It's particularly useful for offloading time-consuming tasks from web requests to background workers.

How It Works

Client                    Job Server                  Worker
   |                          |                          |
   |-- Submit job ----------->|                          |
   |                          |-- Distribute job ------->|
   |                          |                          |
   |                          |<-- Return result --------|
   |<-- Return result --------|                          |

Key Concepts

• Client: Submits jobs to be processed
• Job Server: Coordinates work between clients and workers
• Worker: Executes jobs and returns results
• Jobs: Can be synchronous (blocking) or asynchronous (fire-and-forget)

Example: PHP Worker

<?php
$worker = new GearmanWorker();
$worker->addServer('127.0.0.1', 4730);

$worker->addFunction('resize_image', function($job) {
    $data = json_decode($job->workload(), true);
    $imagePath = $data['path'];
    
    // Perform time-consuming image resize
    $result = resizeImage($imagePath, $data['width'], $data['height']);
    
    return json_encode(['success' => true, 'path' => $result]);
});

while ($worker->work());

Example: PHP Client

<?php
$client = new GearmanClient();
$client->addServer('127.0.0.1', 4730);

// Synchronous (wait for result)
$result = $client->doNormal('resize_image', json_encode([
    'path' => '/images/photo.jpg',
    'width' => 800,
    'height' => 600,
]));

// Asynchronous (fire and forget)
$client->doBackground('send_email', json_encode([
    'to' => 'user@example.com',
    'subject' => 'Welcome!',
]));

Common Use Cases

• Image/video processing
• Email sending
• Report generation
• Data import/export
• Search indexing
• Any CPU-intensive task

What We Like

• Language agnostic: Workers can be written in any language
• Simple protocol: Easy to understand and implement
• Reliable: Job persistence options available
• Scalable: Add workers as needed

What We Don't Like

• Dated: Less actively developed than modern alternatives
• Limited features: No built-in retry, scheduling, or priorities
• Monitoring: Limited visibility without additional tools
• Memory management: Job server can consume significant memory

Modern Alternatives

Alternative	Best For
SQS + Lambda	AWS serverless workloads
Redis + Bull/BullMQ	Node.js applications
Celery	Python applications
Sidekiq	Ruby applications
RabbitMQ	Complex routing needs

Gearman remains useful in legacy PHP environments, but for new projects, we typically recommend cloud-native alternatives like SQS or Redis-based queues.