fix(openai): 统一专属倍率计费链路并补齐回归测试

抽取共享的用户分组专属倍率解析器，统一缓存、singleflight 与回退逻辑。\n\n让 OpenAI 独立计费链路复用专属倍率解析，修复 usage 记录与实际扣费未命中用户专属倍率的问题。\n\n补齐 OpenAI 计费与解析器单元测试，并修复全量回归中暴露的 lint 阻塞项。\n\nCo-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
2026-03-06 14:54:52 +08:00
parent 63a8c76946
commit a18bbb5f2f
8 changed files with 692 additions and 112 deletions
--- a/backend/internal/service/user_group_rate_resolver.go
+++ b/backend/internal/service/user_group_rate_resolver.go
@@ -0,0 +1,103 @@
+package service
+
+import (
+	"context"
+	"fmt"
+	"time"
+
+	"github.com/Wei-Shaw/sub2api/internal/pkg/logger"
+	gocache "github.com/patrickmn/go-cache"
+	"golang.org/x/sync/singleflight"
+)
+
+type userGroupRateResolver struct {
+	repo         UserGroupRateRepository
+	cache        *gocache.Cache
+	cacheTTL     time.Duration
+	sf           *singleflight.Group
+	logComponent string
+}
+
+func newUserGroupRateResolver(repo UserGroupRateRepository, cache *gocache.Cache, cacheTTL time.Duration, sf *singleflight.Group, logComponent string) *userGroupRateResolver {
+	if cacheTTL <= 0 {
+		cacheTTL = defaultUserGroupRateCacheTTL
+	}
+	if cache == nil {
+		cache = gocache.New(cacheTTL, time.Minute)
+	}
+	if logComponent == "" {
+		logComponent = "service.gateway"
+	}
+	if sf == nil {
+		sf = &singleflight.Group{}
+	}
+
+	return &userGroupRateResolver{
+		repo:         repo,
+		cache:        cache,
+		cacheTTL:     cacheTTL,
+		sf:           sf,
+		logComponent: logComponent,
+	}
+}
+
+func (r *userGroupRateResolver) Resolve(ctx context.Context, userID, groupID int64, groupDefaultMultiplier float64) float64 {
+	if r == nil || userID <= 0 || groupID <= 0 {
+		return groupDefaultMultiplier
+	}
+
+	key := fmt.Sprintf("%d:%d", userID, groupID)
+	if r.cache != nil {
+		if cached, ok := r.cache.Get(key); ok {
+			if multiplier, castOK := cached.(float64); castOK {
+				userGroupRateCacheHitTotal.Add(1)
+				return multiplier
+			}
+		}
+	}
+	if r.repo == nil {
+		return groupDefaultMultiplier
+	}
+	userGroupRateCacheMissTotal.Add(1)
+
+	value, err, shared := r.sf.Do(key, func() (any, error) {
+		if r.cache != nil {
+			if cached, ok := r.cache.Get(key); ok {
+				if multiplier, castOK := cached.(float64); castOK {
+					userGroupRateCacheHitTotal.Add(1)
+					return multiplier, nil
+				}
+			}
+		}
+
+		userGroupRateCacheLoadTotal.Add(1)
+		userRate, repoErr := r.repo.GetByUserAndGroup(ctx, userID, groupID)
+		if repoErr != nil {
+			return nil, repoErr
+		}
+
+		multiplier := groupDefaultMultiplier
+		if userRate != nil {
+			multiplier = *userRate
+		}
+		if r.cache != nil {
+			r.cache.Set(key, multiplier, r.cacheTTL)
+		}
+		return multiplier, nil
+	})
+	if shared {
+		userGroupRateCacheSFSharedTotal.Add(1)
+	}
+	if err != nil {
+		userGroupRateCacheFallbackTotal.Add(1)
+		logger.LegacyPrintf(r.logComponent, "get user group rate failed, fallback to group default: user=%d group=%d err=%v", userID, groupID, err)
+		return groupDefaultMultiplier
+	}
+
+	multiplier, ok := value.(float64)
+	if !ok {
+		userGroupRateCacheFallbackTotal.Add(1)
+		return groupDefaultMultiplier
+	}
+	return multiplier
+}