feat: add independent platform modules and multi-provider storage

middleware/idempotency.go

@@ -17,12 +17,13 @@ import (
 )
 
 type IdempotencyConfig struct {
-	TTL              time.Duration `json:"ttl"`
-	MaxEntries       int           `json:"maxEntries"`
-	MaxBytes         int           `json:"maxBytes"`
-	MaxRequestBytes  int64         `json:"maxRequestBytes"`
-	MaxResponseBytes int           `json:"maxResponseBytes"`
-	MaxInFlight      int           `json:"maxInFlight"`
+	Store            IdempotencyStore `json:"-"` // Optional shared store; nil keeps local behavior.
+	TTL              time.Duration    `json:"ttl"`
+	MaxEntries       int              `json:"maxEntries"`
+	MaxBytes         int              `json:"maxBytes"`
+	MaxRequestBytes  int64            `json:"maxRequestBytes"`
+	MaxResponseBytes int              `json:"maxResponseBytes"`
+	MaxInFlight      int              `json:"maxInFlight"`
 	// Scope must return a server-verified tenant/user identity. Register auth
 	// before this middleware. Client-provided identity is not authorization.
 	Scope func(*httpx.Context) (string, error) `json:"-"`
@@ -53,6 +54,9 @@ func NewIdempotency(cfg IdempotencyConfig) (*Idempotency, error) {
 	if cfg.TTL == 0 {
 		cfg.TTL = 10 * time.Minute
 	}
+	if cfg.Store != nil && cfg.TTL > 30*24*time.Hour {
+		return nil, errors.New("middleware: shared idempotency TTL exceeds 30d")
+	}
 	if cfg.MaxEntries == 0 {
 		cfg.MaxEntries = 256
 	}
@@ -125,6 +129,9 @@ func (i *Idempotency) Middleware() httpx.Middleware {
 			copy(fingerprint[:], hash.Sum(nil))
 			namespace, _ := json.Marshal([]string{scope, key})
 			id := sha256.Sum256(namespace)
+			if i.config.Store != nil {
+				return i.shared(c, next, id, fingerprint)
+			}
 			i.mu.Lock()
 			now := i.now()
 			for k, v := range i.items {