first commit

backend/internal/repository/gateway_cache.go

@@ -0,0 +1,41 @@
+package repository
+
+import (
+	"context"
+	"fmt"
+	"time"
+
+	"github.com/Wei-Shaw/sub2api/internal/service"
+	"github.com/redis/go-redis/v9"
+)
+
+const stickySessionPrefix = "sticky_session:"
+
+type gatewayCache struct {
+	rdb *redis.Client
+}
+
+func NewGatewayCache(rdb *redis.Client) service.GatewayCache {
+	return &gatewayCache{rdb: rdb}
+}
+
+// buildSessionKey 构建 session key，包含 groupID 实现分组隔离
+// 格式: sticky_session:{groupID}:{sessionHash}
+func buildSessionKey(groupID int64, sessionHash string) string {
+	return fmt.Sprintf("%s%d:%s", stickySessionPrefix, groupID, sessionHash)
+}
+
+func (c *gatewayCache) GetSessionAccountID(ctx context.Context, groupID int64, sessionHash string) (int64, error) {
+	key := buildSessionKey(groupID, sessionHash)
+	return c.rdb.Get(ctx, key).Int64()
+}
+
+func (c *gatewayCache) SetSessionAccountID(ctx context.Context, groupID int64, sessionHash string, accountID int64, ttl time.Duration) error {
+	key := buildSessionKey(groupID, sessionHash)
+	return c.rdb.Set(ctx, key, accountID, ttl).Err()
+}
+
+func (c *gatewayCache) RefreshSessionTTL(ctx context.Context, groupID int64, sessionHash string, ttl time.Duration) error {
+	key := buildSessionKey(groupID, sessionHash)
+	return c.rdb.Expire(ctx, key, ttl).Err()
+}