gofiber/fiber · error

cache: failed to get key %q from storage: %w

Error message

cache: failed to get key %q from storage: %w

What it means

Thrown by the cache middleware's manager.get() at middleware/cache/manager.go:114 when the configured fiber.Storage backend returns a non-nil error from GetWithContext while reading a cache entry. The wrapped %w is the raw driver error (Redis/MySQL/SQLite/etc.). It means the storage layer itself is failing, not that the key is missing (a miss returns the internal errCacheMiss sentinel instead).

Source

Thrown at middleware/cache/manager.go:114

	e.status = 0
	e.age = 0
	e.exp = 0
	e.ttl = 0
	e.forceRevalidate = false
	e.revalidate = false
	e.headers = nil
	e.shareable = false
	e.private = false
	e.heapidx = 0
	m.pool.Put(e)
}

// get data from storage or memory
func (m *manager) get(ctx context.Context, key string) (*item, error) {
	if m.storage != nil {
		raw, err := m.storage.GetWithContext(ctx, key)
		if err != nil {
			return nil, fmt.Errorf("cache: failed to get key %q from storage: %w", m.logKey(key), err)
		}
		if raw == nil {
			return nil, errCacheMiss
		}

		it := m.acquire()
		if _, err := it.UnmarshalMsg(raw); err != nil {
			m.release(it)
			return nil, fmt.Errorf("cache: failed to unmarshal key %q: %w", m.logKey(key), err)
		}

		return it, nil
	}

	if value := m.memory.Get(key); value != nil {
		it, ok := value.(*item)
		if !ok {
			return nil, fmt.Errorf("cache: unexpected entry type %T for key %q", value, m.logKey(key))

View on GitHub (pinned to 9a4c7e57fe)

Solutions

1. Inspect the wrapped error string for the underlying driver cause (e.g. 'connection refused', 'i/o timeout', 'context deadline exceeded') and fix that specific backend issue.
2. Verify the storage instance is healthy and reachable from the app pod (ping / health-check the endpoint configured on the storage driver).
3. If the wrapped error is context.DeadlineExceeded, raise the storage driver's read timeout or the fiber handler's per-request timeout to exceed typical backend latency.
4. Add connection-pool tuning / retries on the storage driver (e.g. Redis PoolSize, MinIdleConns) to survive transient failures.
5. Wire a fiber.ErrorHandler that logs the storage error and degrades gracefully (serves an uncached response) instead of 500-ing every request when storage flaps.

Example fix

// before
app.Use(cache.New(cache.Config{
    Storage: redis.New(), // no timeout, no pool tuning
}))

// after
store := redis.New(redis.Config{
    URL:   os.Getenv("REDIS_URL"),
    PoolSize: 50,
})
if err := store.Reset(); err != nil { // sanity check connectivity at boot
    log.Fatalf("cache storage unreachable: %v", err)
}
app.Use(cache.New(cache.Config{ Storage: store }))

// At boot, confirm the storage backend is reachable before wiring the cache.
ctx, cancel := context.WithTimeout(context.Background(), 2*time.Second)
defer cancel()
if _, err := store.GetWithContext(ctx, "__healthcheck__"); err != nil {
    log.Fatalf("cache storage unhealthy: %v", err)
}

// cache errors bubble through fiber's error handler; log + degrade there.
app.ErrorHandler = func(c fiber.Ctx, err error) error {
    if strings.Contains(err.Error(), "cache: failed to get key") {
        log.Printf("cache read failed (serving uncached): %v", err)
        return c.Next()
    }
    return fiber.DefaultErrorHandler(c, err)
}

When it happens

Trigger: Cache middleware is configured with Storage: someStorage (e.g. storage.Redis, storage.S3, storage.SQLite) and a request hits a cached route while that backend is unreachable, times out, or returns a query error. The ctx passed to GetWithContext may also be cancelled, surfacing as context.Canceled / context.DeadlineExceeded inside the wrapped error.

Common situations: Redis connection dropped or AUTH expired; DB connection pool exhausted under load; storage pods restarted during a deploy; client request cancelled (ctx done) before the storage GET returns; network partition between the app and the storage host; misconfigured storage TLS.

Related errors

• cache: failed to get raw key %q from storage: %w
• cache: failed to store key %q: %w
• cache: failed to store raw key %q: %w
• cache: failed to delete key %q: %w
• cache: failed to reload key %q after eviction failure: %w

AI-assisted analysis of gofiber/fiber@9a4c7e57fe (2026-08-04). Data as JSON: /data/errors/67c5ac08fafc3b7f.json. Report an issue: GitHub.