Laravel Job Batching

Laravel's job batching feature allows you to group multiple jobs into a batch and perform actions when the batch completes, fails, or progresses. This is particularly useful for tasks like processing large datasets or executing dependent jobs.

Defining Batchable Jobs

To make a job batchable, include the Illuminate\Bus\Batchable trait in your job class. This provides access to the batch() method, which allows the job to interact with its batch. For example:

namespace App\Jobs;

use Illuminate\Bus\Batchable;

use Illuminate\Contracts\Queue\ShouldQueue;

use Illuminate\Foundation\Queue\Queueable;

class ImportCsv implements ShouldQueue

{

use Batchable, Queueable;

public function handle(): void

{

if ($this->batch()->cancelled()) {

// Stop processing if the batch is cancelled

return;

}

// Process the CSV data

}

Dispatching Job Batches

You can dispatch a batch of jobs using the Bus::batch() method. This method also supports completion callbacks like then, catch, and finally:

use App\Jobs\ImportCsv;

use Illuminate\Bus\Batch;

use Illuminate\Support\Facades\Bus;

$batch = Bus::batch([

new ImportCsv(1, 100),

new ImportCsv(101, 200),

new ImportCsv(201, 300),

])->then(function (Batch $batch) {

// All jobs completed successfully

})->catch(function (Batch $batch, Throwable $e) {

// Handle the first job failure

})->finally(function (Batch $batch) {

// The batch has finished executing

})->dispatch();

Monitoring and Managing Batches

Laravel provides tools to inspect and manage batches:

$batch->progress() returns the completion percentage.
$batch->cancel() cancels the batch.
$batch->failedJobs retrieves the number of failed jobs.

You can also retrieve a batch by its ID using Bus::findBatch($batchId).

Adding Jobs Dynamically

You can add jobs to an existing batch from within a batch job using the add() method:

$this->batch()->add([

new ImportCsv(401, 500),

new ImportCsv(501, 600),

]);

Batch Failures and Pruning

When a job in a batch fails, the catch callback is triggered. By default, a failed job cancels the entire batch, but you can override this behavior using the allowFailures() method. To clean up old batch records, schedule the queue:prune-batches Artisan command.

Important Considerations

Database Migration: Ensure you have a job_batches table by running php artisan make:queue-batches-table and migrating it.
Callbacks: Avoid using $this in batch callbacks as they are serialized.
Batch Naming: Use the name() method to assign a name for better debugging in tools like Horizon.

Laravel's job batching simplifies handling complex workflows by grouping jobs and providing robust tools for monitoring and managing their execution.