README

Circuit breaker for Laravel queue jobs

Protect your queue workers from cascading failures when external services go down.

The Problem

When Stripe goes down at 11 PM, your queue workers don't know. They keep trying to charge customers. Each job waits 30 seconds for a timeout. Then retries. Waits again. Your entire queue system freezes.

Without Fuse: 10,000 jobs × 30-second timeouts = 25+ hours to clear the queue.

With Fuse: Circuit opens after 5 failures. Queue clears in 10 seconds. Automatic recovery when the service returns.

Features

• Three-State Circuit Breaker — CLOSED (normal), OPEN (protected), HALF-OPEN (testing recovery)
• Intelligent Failure Classification — 429 rate limits and auth errors don't trip the circuit
• Peak Hours Support — Different thresholds for business hours vs. off-peak
• Fixed Window Tracking — Minute-based buckets with automatic expiration, no cleanup needed
• Thundering Herd Prevention — Cache::lock() ensures only one worker probes during recovery
• Zero Data Loss — Jobs are delayed with release(), not failed permanently
• Automatic Recovery — Circuit tests and heals itself when services return
• Per-Service Circuits — Separate breakers for Stripe, Mailgun, your microservices
• Laravel Events — Get notified on state transitions for alerting and monitoring
• Real-Time Status Page — Built-in monitoring dashboard with live state updates
• Pure Laravel — No external dependencies, uses Cache and native job middleware

How It Works

CLOSED — Normal operations. All requests pass through. Failures are tracked in the background.

OPEN — Protection mode. After the failure threshold is exceeded, the circuit trips. Jobs fail instantly (1ms, not 30s) and are delayed for automatic retry. No API calls are made.

HALF-OPEN — Testing recovery. After the timeout period, one probe request tests if the service recovered. Success closes the circuit. Failure reopens it.

Installation

composer require harris21/laravel-fuse

Publish the configuration:

php artisan vendor:publish --tag=fuse-config

Quick Start

Add the middleware to your job:

use Harris21\Fuse\Middleware\CircuitBreakerMiddleware;

class ChargeCustomer implements ShouldQueue
{
    public $tries = 0;           // Unlimited releases
    public $maxExceptions = 3;   // Only real failures count

    public function middleware(): array
    {
        return [new CircuitBreakerMiddleware('stripe')];
    }

    public function handle(): void
    {
        // Your payment logic - unchanged
        Stripe::charges()->create([...]);
    }
}

That's it. Your job is now protected.

Configuration

// config/fuse.php

return [
    'enabled' => env('FUSE_ENABLED', true),

    'default_threshold' => 50,      // Failure rate percentage to trip circuit
    'default_timeout' => 60,        // Seconds before testing recovery
    'default_min_requests' => 10,   // Minimum requests before evaluating

    'services' => [
        'stripe' => [
            'threshold' => 50,
            'timeout' => 30,
            'min_requests' => 5,

            // Peak hours: more tolerant during business hours
            'peak_hours_threshold' => 60,
            'peak_hours_start' => 9,   // 9 AM
            'peak_hours_end' => 17,    // 5 PM
        ],
        'mailgun' => [
            'threshold' => 60,
            'timeout' => 120,
            'min_requests' => 10,
        ],
    ],

    // Cache prefix — change if multiple apps share the same Redis instance
    'cache' => [
        'prefix' => env('FUSE_CACHE_PREFIX', 'fuse'),
    ],
];

Peak Hours

Configure different thresholds for business hours when every transaction matters:

'stripe' => [
    'threshold' => 40,              // Off-peak: more sensitive (40%)
    'peak_hours_threshold' => 60,   // Peak hours: more tolerant (60%)
    'peak_hours_start' => 9,        // 9 AM
    'peak_hours_end' => 17,         // 5 PM
],

During peak hours (9 AM - 5 PM), the circuit uses the higher threshold to maximize successful transactions. Outside peak hours, it uses the lower threshold for earlier protection.

Intelligent Failure Classification

Not all errors indicate a service is down. Fuse only counts real outages:

This prevents false positives. A rate limit doesn't mean Stripe is down - it means you're sending too many requests.

Custom Failure Classification

The default behavior works well for most APIs, but some services deviate from HTTP standards. For example, Stripe returns 500 for idempotency errors that are actually client-side issues — not outages.

You can override the failure classification logic per service by setting the failure_classifier option in your service config:

// config/fuse.php

'services' => [
    'stripe' => [
        'threshold' => 50,
        'timeout' => 30,
        'min_requests' => 5,
        'failure_classifier' => \App\Fuse\StripeFailureClassifier::class,
    ],
],

Extending the Default Classifier

The easiest approach is to extend DefaultFailureClassifier and override specific cases:

namespace App\Fuse;

use GuzzleHttp\Exception\ServerException;
use Harris21\Fuse\Classifiers\DefaultFailureClassifier;
use Throwable;

class StripeFailureClassifier extends DefaultFailureClassifier
{
    public function shouldCount(Throwable $e): bool
    {
        // Stripe returns 500 for idempotency errors — not a real outage
        if ($e instanceof ServerException) {
            $body = (string) $e->getResponse()?->getBody();

            if (str_contains($body, 'idempotency')) {
                return false;
            }
        }

        return parent::shouldCount($e);
    }
}

Implementing the Interface from Scratch

For full control, implement FailureClassifier directly:

namespace App\Fuse;

use Harris21\Fuse\Contracts\FailureClassifier;
use Throwable;

class CustomFailureClassifier implements FailureClassifier
{
    public function shouldCount(Throwable $e): bool
    {
        // Your classification logic
    }
}

When no failure_classifier is configured, Fuse uses DefaultFailureClassifier which preserves the behavior described in the table above.

Events

Fuse dispatches Laravel events on every state transition:

use Harris21\Fuse\Events\CircuitBreakerOpened;
use Harris21\Fuse\Events\CircuitBreakerHalfOpen;
use Harris21\Fuse\Events\CircuitBreakerClosed;

Listening to Events

// app/Listeners/AlertOnCircuitOpen.php

class AlertOnCircuitOpen
{
    public function handle(CircuitBreakerOpened $event): void
    {
        Log::critical("Circuit breaker opened for {$event->service}", [
            'failure_rate' => $event->failureRate,
            'attempts' => $event->attempts,
            'failures' => $event->failures,
        ]);

        // Send Slack notification, page on-call, etc.
    }
}

Event Properties

CircuitBreakerOpened:

• $service — The service name (e.g., "stripe")
• $failureRate — Current failure percentage
• $attempts — Total requests in the window
• $failures — Failed requests in the window

CircuitBreakerHalfOpen:

• $service — The service name

CircuitBreakerClosed:

• $service — The service name

Status Page

Fuse includes a real-time monitoring dashboard that shows the state of all your circuit breakers.

Enable the Status Page

Add to your .env:

FUSE_STATUS_PAGE_ENABLED=true

The status page is available at /fuse (configurable via FUSE_STATUS_PAGE_PREFIX).

Authorization

Access is controlled by a viewFuse gate. By default, only the local environment is allowed. Override it in your AppServiceProvider:

use Illuminate\Support\Facades\Gate;

Gate::define('viewFuse', function ($user = null) {
    return $user?->isAdmin();
});

Configuration

// config/fuse.php

'status_page' => [
    'enabled' => env('FUSE_STATUS_PAGE_ENABLED', false),
    'prefix' => env('FUSE_STATUS_PAGE_PREFIX', 'fuse'),
    'middleware' => [],          // Custom middleware (replaces default)
    'polling_interval' => 2,    // Frontend refresh interval in seconds
],

What It Shows

• Circuit state for each configured service (CLOSED, OPEN, HALF-OPEN)
• State history with timestamped transitions
• Live stats — attempts, failures, failure rate per window
• Recovery info — when the circuit opened and when it will test recovery
• Auto-refresh — polls the backend every 2 seconds (configurable)

Fallback Strategies

When the circuit opens, your application needs a plan. Here are common strategies:

Return cached data — Show last known prices, cached shipping rates, or stale product info. Slightly stale data beats an error page.

Use a fallback service — Switch to a backup payment provider, or show "payment pending" and queue it for later.

Queue for later — Fuse already does this with release(). For synchronous requests, dispatch a job to retry when the circuit closes.

Graceful degradation — Hide the feature entirely. Can't load recommendations? Don't show that section. The page still works.

Direct Usage

Use the circuit breaker directly outside of jobs:

use Harris21\Fuse\CircuitBreaker;

$breaker = new CircuitBreaker('stripe');

if (!$breaker->isOpen()) {
    try {
        $result = Stripe::charges()->create([...]);
        $breaker->recordSuccess();
        return $result;
    } catch (Exception $e) {
        $breaker->recordFailure($e);
        throw $e;
    }
} else {
    // Circuit is open - use fallback
    return $this->fallbackResponse();
}

Check Circuit State

$breaker = new CircuitBreaker('stripe');

$breaker->isClosed();    // Normal operations
$breaker->isOpen();      // Protected, failing fast
$breaker->isHalfOpen();  // Testing recovery

$breaker->getStats();    // Get full statistics
$breaker->reset();       // Manually reset to closed

Requirements

• PHP 8.3+
• Laravel 11+
• Redis recommended for production, file cache may have race conditions during recovery probing

Credits

Built by Harris Raftopoulos for Laracon India 2026.

YouTube: @harrisrafto

Based on the circuit breaker pattern from Michael Nygard's Release It! and popularized by Martin Fowler.

License

MIT