gofiber/fiber · error

cache: failed to get key

Error message

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

What it means

Returned by manager.get when an external Storage backend's GetWithContext call errors while fetching a cached item. This is the cache-read path: the middleware tried to retrieve a previously stored response from the configured Storage and the backend reported a failure (not a miss — a miss returns errCacheMiss when raw==nil).

Solutions

  1. Check the wrapped error — for context cancellation (errors.Is(err, context.Canceled|context.DeadlineExceeded)) the client disconnected; no action needed.
  2. Verify Storage connectivity and credentials (ping the backend directly outside Fiber).
  3. Tune the Storage driver's connection pool, dial/read/write timeouts to match your latency budget.
  4. If recurring, add health checks / circuit-breaking around the Storage so transient outages degrade gracefully to uncached responses instead of erroring.

Example fix

// The cache middleware should treat storage errors as a miss, not a request failure:
// before
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)
}

// after (defensive fallback to miss on transient storage errors)
raw, err := m.storage.GetWithContext(ctx, key)
if err != nil {
    if errors.Is(err, context.Canceled) || errors.Is(err, context.DeadlineExceeded) {
        return nil, err // propagate only client-driven cancellation
    }
    log.Warn("cache storage get failed, treating as miss:", err)
    return nil, errCacheMiss
}
Defensive patterns

Strategy: retry

Validate before calling

// Before serving traffic, confirm Storage is reachable and the key namespace is clean.
func checkCacheStorage(ctx context.Context, s fiber.Storage) error {
    probe := []byte("ok")
    if err := s.SetWithContext(ctx, "__cache_probe__", probe, time.Second); err != nil {
        return fmt.Errorf("storage write check failed: %w", err)
    }
    got, err := s.GetWithContext(ctx, "__cache_probe__")
    if err != nil {
        return fmt.Errorf("storage read check failed: %w", err)
    }
    if !bytes.Equal(got, probe) {
        return fmt.Errorf("storage roundtrip mismatch")
    }
    _ = s.DeleteWithContext(ctx, "__cache_probe__")
    return nil
}

Try / catch

// Classify before acting: cancellation propagates, other errors degrade to miss.
raw, err := m.storage.GetWithContext(ctx, key)
if err != nil {
    if errors.Is(err, context.Canceled) || errors.Is(err, context.DeadlineExceeded) {
        return nil, err
    }
    // transient storage error -> treat as miss, optionally retry once
    return nil, errCacheMiss
}

Prevention

When it happens

Trigger: Any cache lookup (GET request hitting the cache middleware with a populated cfg.Storage) where Storage.GetWithContext returns a non-nil error: Redis unreachable, connection pool exhausted, storage backend returning a protocol/deserialization error, context canceled or deadline exceeded.

Common situations: Redis/Valkey connection dropped or misconfigured (wrong address/auth); storage driver timeout shorter than load; TLS handshake failures to managed Redis; context cancellation from client disconnect propagating into the storage call; storage backend OOM or failover.

Related errors

AI-assisted analysis of gofiber/fiber@a105acad6c (2026-08-11). Data as JSON: /api/errors/67c5ac08fafc3b7f. Report an issue: GitHub.

Appendix: 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 a105acad6c)