feat: edge gateway service

gateway/internal/replay/redis.go

@@ -0,0 +1,131 @@
+package replay
+
+import (
+	"context"
+	"crypto/tls"
+	"encoding/base64"
+	"errors"
+	"fmt"
+	"strings"
+	"time"
+
+	"galaxy/gateway/internal/config"
+
+	"github.com/redis/go-redis/v9"
+)
+
+// RedisStore implements Store with Redis SETNX reservations over a dedicated
+// key namespace.
+type RedisStore struct {
+	client         *redis.Client
+	keyPrefix      string
+	reserveTimeout time.Duration
+}
+
+// NewRedisStore constructs a Redis-backed replay store that reuses the
+// SessionCache Redis deployment settings and applies the replay-specific key
+// namespace and timeout controls from replayCfg.
+func NewRedisStore(sessionCfg config.SessionCacheRedisConfig, replayCfg config.ReplayRedisConfig) (*RedisStore, error) {
+	if strings.TrimSpace(sessionCfg.Addr) == "" {
+		return nil, errors.New("new redis replay store: redis addr must not be empty")
+	}
+	if sessionCfg.DB < 0 {
+		return nil, errors.New("new redis replay store: redis db must not be negative")
+	}
+	if strings.TrimSpace(replayCfg.KeyPrefix) == "" {
+		return nil, errors.New("new redis replay store: replay key prefix must not be empty")
+	}
+	if replayCfg.ReserveTimeout <= 0 {
+		return nil, errors.New("new redis replay store: reserve timeout must be positive")
+	}
+
+	options := &redis.Options{
+		Addr:            sessionCfg.Addr,
+		Username:        sessionCfg.Username,
+		Password:        sessionCfg.Password,
+		DB:              sessionCfg.DB,
+		Protocol:        2,
+		DisableIdentity: true,
+	}
+	if sessionCfg.TLSEnabled {
+		options.TLSConfig = &tls.Config{MinVersion: tls.VersionTLS12}
+	}
+
+	return &RedisStore{
+		client:         redis.NewClient(options),
+		keyPrefix:      replayCfg.KeyPrefix,
+		reserveTimeout: replayCfg.ReserveTimeout,
+	}, nil
+}
+
+// Close releases the underlying Redis client resources.
+func (s *RedisStore) Close() error {
+	if s == nil || s.client == nil {
+		return nil
+	}
+
+	return s.client.Close()
+}
+
+// Ping verifies that the configured Redis backend is reachable within the
+// replay reserve timeout budget.
+func (s *RedisStore) Ping(ctx context.Context) error {
+	if s == nil || s.client == nil {
+		return errors.New("ping redis replay store: nil store")
+	}
+	if ctx == nil {
+		return errors.New("ping redis replay store: nil context")
+	}
+
+	pingCtx, cancel := context.WithTimeout(ctx, s.reserveTimeout)
+	defer cancel()
+
+	if err := s.client.Ping(pingCtx).Err(); err != nil {
+		return fmt.Errorf("ping redis replay store: %w", err)
+	}
+
+	return nil
+}
+
+// Reserve records the authenticated deviceSessionID and requestID pair for
+// ttl. It rejects duplicates while the reservation remains active.
+func (s *RedisStore) Reserve(ctx context.Context, deviceSessionID string, requestID string, ttl time.Duration) error {
+	if s == nil || s.client == nil {
+		return errors.New("reserve replay request in redis: nil store")
+	}
+	if ctx == nil {
+		return errors.New("reserve replay request in redis: nil context")
+	}
+	if strings.TrimSpace(deviceSessionID) == "" {
+		return errors.New("reserve replay request in redis: empty device session id")
+	}
+	if strings.TrimSpace(requestID) == "" {
+		return errors.New("reserve replay request in redis: empty request id")
+	}
+	if ttl <= 0 {
+		return errors.New("reserve replay request in redis: ttl must be positive")
+	}
+
+	reserveCtx, cancel := context.WithTimeout(ctx, s.reserveTimeout)
+	defer cancel()
+
+	reserved, err := s.client.SetNX(reserveCtx, s.reservationKey(deviceSessionID, requestID), "1", ttl).Result()
+	if err != nil {
+		return fmt.Errorf("reserve replay request in redis: %w", err)
+	}
+	if !reserved {
+		return fmt.Errorf("reserve replay request in redis: %w", ErrDuplicate)
+	}
+
+	return nil
+}
+
+func (s *RedisStore) reservationKey(deviceSessionID string, requestID string) string {
+	return s.keyPrefix + encodeKeyComponent(deviceSessionID) + ":" + encodeKeyComponent(requestID)
+}
+
+func encodeKeyComponent(value string) string {
+	return base64.RawURLEncoding.EncodeToString([]byte(value))
+}
+
+var _ Store = (*RedisStore)(nil)