Redis Patterns

Redis Patterns

Constraints

• Apply @rules/laravel/laravel.mdc — use the framework's facades (Cache, RateLimiter, Redis), not a raw client.
• Apply @rules/laravel/queue-debouncing.mdc for queue/job coalescing concerns when Redis backs the queue.
• Cross-link @rules/sql/optimalize.mdc (DB-level caching) — Redis caching sits in front of the query tuning that rule owns; cache the result, do not paper over an unindexed query.
• final classes, declare(strict_types=1), Pest tests (use the array cache driver in tests unless asserting Redis-specific behavior).
• Always set a TTL. Keys without expiry accumulate and cause memory pressure.

Use when

• Adding caching, rate limiting, distributed coordination, or pub/sub to a Laravel app.
• Choosing a cache strategy, protecting a cold cache from stampede, or designing key/TTL conventions.
• Configuring Redis as the session, cache, or queue store.

Use Laravel facades throughout. Reach for raw Redis::command(...) only for structures the Cache abstraction does not expose (sorted sets, streams).

Caching Strategies

Cache-Aside (default for read-heavy data)

$product = Cache::remember("product:{$id}", now()->addMinutes(10), fn () =>
    Product::findOrFail($id),
);

remember() is read-through cache-aside: returns the cached value or runs the closure, stores it, and returns it. Use rememberForever() only with an explicit invalidation path.

Write-Through (consistency required)

$product->update($data);
Cache::put("product:{$product->id}", $product->fresh(), now()->addMinutes(10));
// Or simply invalidate so the next read repopulates:
Cache::forget("product:{$product->id}");

Invalidate (forget) rather than rewrite when the cached shape may differ from the model.

Cache Tags (grouped invalidation)

Cache::tags(['products', "category:{$categoryId}"])
    ->remember("product:{$id}", now()->addMinutes(10), fn () => Product::findOrFail($id));

Cache::tags(["category:{$categoryId}"])->flush(); // drop the whole group at once

Tags require the redis (or memcached) store — not file/database. They add key overhead; use for genuine groups, not single keys.

Stampede Protection

A cold/expired hot key can trigger many concurrent rebuilds (thundering herd). Guard the rebuild with an atomic lock so only one worker recomputes.

public function getReport(string $key): array
{
    return Cache::get($key) ?? Cache::lock("rebuild:{$key}", seconds: 10)->block(5, function () use ($key) {
        // Re-check inside the lock — another worker may have just populated it.
        return Cache::get($key) ?? tap($this->computeReport(), fn ($v) =>
            Cache::put($key, $v, now()->addMinutes(15)),
        );
    });
}

• Cache::lock() is an atomic SET NX PX lock; block(5, ...) waits up to 5s to acquire.
• Alternative for very hot keys: stale-while-revalidate — serve the slightly stale value while one worker refreshes in the background, avoiding any blocking.

Distributed Locks

Coordinate exclusive access across workers/requests.

$lock = Cache::lock('payment:'.$orderId, seconds: 30);
if ($lock->get()) {
    try {
        $this->processPayment($orderId);
    } finally {
        $lock->release(); // always release in finally
    }
}

• The TTL must exceed the expected work; on crash the lock auto-expires so it never wedges permanently.
• Only the owner may release — Laravel tracks the owner token, so release() is safe. Use forceRelease() only deliberately.
• For bounded concurrency (N parallel, not 1), use Redis::funnel('job')->limit(3)->then(fn () => ...).

Rate Limiting

Prefer the framework limiter over hand-rolled counters.

use Illuminate\Support\Facades\RateLimiter;

$executed = RateLimiter::attempt("send:{$user->id}", maxAttempts: 5, function (): void {
    $this->sendMessage();
}, decaySeconds: 60);

if (! $executed) {
    abort(429); // or RateLimiter::availableIn($key) for retry hint
}

• HTTP routes: define a named limiter (RateLimiter::for('api', fn ($r) => Limit::perMinute(60)->by($r->user()?->id ?: $r->ip()))) and apply throttle:api middleware.
• For high-throughput throttling, Redis::throttle('key')->allow(60)->every(60)->then($ok, $tooMany) runs the check in a single atomic Redis call.

Key Naming & TTL Discipline

{app}:{resource}:{id}            myapp:product:123
{app}:{resource}:{id}:{field}    myapp:order:456:status
{app}:{resource}:{date}          myapp:stats:pageviews:2026-06-14

• Use Laravel's cache.prefix for the app namespace; do not hand-prefix every key.
• Never run KEYS * in production (O(N), blocks the server) — use SCAN via Redis::scan().

Eviction Policy

Set maxmemory + maxmemory-policy in redis.conf per role:

Critical: do not point a Redis queue/session connection at an allkeys-lru instance — it will silently evict jobs/sessions. Separate the cache instance/DB from the queue instance.

Pub/Sub

Fire-and-forget broadcast; no delivery guarantee or replay.

Redis::publish('orders', json_encode(['id' => $order->id]));

// Long-running listener (artisan command):
Redis::subscribe(['orders'], function (string $message): void {
    $this->handle(json_decode($message, true));
});

If you need durability, consumer groups, or replay, use the Laravel queue (below) or Redis Streams via Redis::command('XADD', ...) — Pub/Sub drops messages for absent subscribers.

Pipelines & Transactions

Batch many commands in one round trip; use a transaction when they must apply atomically.

Redis::pipeline(function ($pipe) use ($ids): void {
    foreach ($ids as $id) {
        $pipe->del("product:{$id}");
    }
}); // one round trip, NOT atomic

Redis::transaction(function ($tx) use ($key): void {
    $tx->incr($key);
    $tx->expire($key, 60);
}); // MULTI/EXEC — all-or-nothing

Pipelines cut latency for bulk ops; transactions add atomicity. Do not loop single commands when a pipeline fits.

Queues, Sessions & Stores

• Queues: set QUEUE_CONNECTION=redis. Run Laravel Horizon for Redis queues — it gives supervisor config, metrics, and a dashboard. For coalescing bursty jobs see @rules/laravel/queue-debouncing.mdc.
• Sessions / cache: SESSION_DRIVER=redis, CACHE_STORE=redis. Keep sessions/queue on a noeviction instance and cache on an allkeys-lru instance (or distinct DB indexes) so cache eviction never drops a session or job.
• Size the predis/phpredis pool and set socket_timeout / read_timeout so a stalled Redis fails fast instead of hanging requests.

Done when

• Every key has an intentional TTL and follows the naming convention.
• Hot/cold cache rebuilds are stampede-protected with Cache::lock.
• Cache and queue/session use separate instances or DBs with matching eviction policies.
• Rate limiting uses RateLimiter / Redis::throttle, not ad-hoc counters.
• Pest tests cover cache hit/miss and lock paths; no KEYS * in production code.