fix(仪表盘): 修复缓存稳定性并补充测试

backend/internal/repository/dashboard_cache.go

@@ -22,6 +22,9 @@ func NewDashboardCache(rdb *redis.Client, cfg *config.Config) service.DashboardS
 	if cfg != nil {
 		prefix = strings.TrimSpace(cfg.Dashboard.KeyPrefix)
 	}
+	if prefix != "" && !strings.HasSuffix(prefix, ":") {
+		prefix += ":"
+	}
 	return &dashboardCache{
 		rdb:       rdb,
 		keyPrefix: prefix,
@@ -49,3 +52,7 @@ func (c *dashboardCache) buildKey() string {
 	}
 	return c.keyPrefix + dashboardStatsCacheKey
 }
+
+func (c *dashboardCache) DeleteDashboardStats(ctx context.Context) error {
+	return c.rdb.Del(ctx, c.buildKey()).Err()
+}

backend/internal/repository/dashboard_cache_test.go

@@ -0,0 +1,28 @@
+package repository
+
+import (
+	"testing"
+
+	"github.com/Wei-Shaw/sub2api/internal/config"
+	"github.com/stretchr/testify/require"
+)
+
+func TestNewDashboardCacheKeyPrefix(t *testing.T) {
+	cache := NewDashboardCache(nil, &config.Config{
+		Dashboard: config.DashboardCacheConfig{
+			KeyPrefix: "prod",
+		},
+	})
+	impl, ok := cache.(*dashboardCache)
+	require.True(t, ok)
+	require.Equal(t, "prod:", impl.keyPrefix)
+
+	cache = NewDashboardCache(nil, &config.Config{
+		Dashboard: config.DashboardCacheConfig{
+			KeyPrefix: "staging:",
+		},
+	})
+	impl, ok = cache.(*dashboardCache)
+	require.True(t, ok)
+	require.Equal(t, "staging:", impl.keyPrefix)
+}

backend/internal/service/dashboard_service.go

@@ -26,6 +26,7 @@ var ErrDashboardStatsCacheMiss = errors.New("仪表盘缓存未命中")
 type DashboardStatsCache interface {
 	GetDashboardStats(ctx context.Context) (string, error)
 	SetDashboardStats(ctx context.Context, data string, ttl time.Duration) error
+	DeleteDashboardStats(ctx context.Context) error
 }
 
 type dashboardStatsCacheEntry struct {
@@ -115,10 +116,12 @@ func (s *DashboardService) getCachedDashboardStats(ctx context.Context) (*usages
 
 	var entry dashboardStatsCacheEntry
 	if err := json.Unmarshal([]byte(data), &entry); err != nil {
-		return nil, false, err
+		s.evictDashboardStatsCache(err)
+		return nil, false, ErrDashboardStatsCacheMiss
 	}
 	if entry.Stats == nil {
-		return nil, false, errors.New("仪表盘缓存缺少统计数据")
+		s.evictDashboardStatsCache(errors.New("仪表盘缓存缺少统计数据"))
+		return nil, false, ErrDashboardStatsCacheMiss
 	}
 
 	age := time.Since(time.Unix(entry.UpdatedAt, 0))
@@ -130,7 +133,9 @@ func (s *DashboardService) refreshDashboardStats(ctx context.Context) (*usagesta
 	if err != nil {
 		return nil, err
 	}
-	s.saveDashboardStatsCache(ctx, stats)
+	cacheCtx, cancel := s.cacheOperationContext()
+	defer cancel()
+	s.saveDashboardStatsCache(cacheCtx, stats)
 	return stats, nil
 }
 
@@ -153,7 +158,9 @@ func (s *DashboardService) refreshDashboardStatsAsync() {
 			log.Printf("[Dashboard] 仪表盘缓存异步刷新失败: %v", err)
 			return
 		}
-		s.saveDashboardStatsCache(ctx, stats)
+		cacheCtx, cancel := s.cacheOperationContext()
+		defer cancel()
+		s.saveDashboardStatsCache(cacheCtx, stats)
 	}()
 }
 
@@ -177,6 +184,25 @@ func (s *DashboardService) saveDashboardStatsCache(ctx context.Context, stats *u
 	}
 }
 
+func (s *DashboardService) evictDashboardStatsCache(reason error) {
+	if s.cache == nil {
+		return
+	}
+	cacheCtx, cancel := s.cacheOperationContext()
+	defer cancel()
+
+	if err := s.cache.DeleteDashboardStats(cacheCtx); err != nil {
+		log.Printf("[Dashboard] 仪表盘缓存清理失败: %v", err)
+	}
+	if reason != nil {
+		log.Printf("[Dashboard] 仪表盘缓存异常，已清理: %v", reason)
+	}
+}
+
+func (s *DashboardService) cacheOperationContext() (context.Context, context.CancelFunc) {
+	return context.WithTimeout(context.Background(), s.refreshTimeout)
+}
+
 func (s *DashboardService) GetAPIKeyUsageTrend(ctx context.Context, startTime, endTime time.Time, granularity string, limit int) ([]usagestats.APIKeyUsageTrendPoint, error) {
 	trend, err := s.usageRepo.GetAPIKeyUsageTrend(ctx, startTime, endTime, granularity, limit)
 	if err != nil {

backend/internal/service/dashboard_service_test.go

@@ -3,6 +3,7 @@ package service
 import (
 	"context"
 	"encoding/json"
+	"errors"
 	"sync"
 	"sync/atomic"
 	"testing"
@@ -38,8 +39,10 @@ func (s *usageRepoStub) GetDashboardStats(ctx context.Context) (*usagestats.Dash
 type dashboardCacheStub struct {
 	get       func(ctx context.Context) (string, error)
 	set       func(ctx context.Context, data string, ttl time.Duration) error
+	del       func(ctx context.Context) error
 	getCalls  int32
 	setCalls  int32
+	delCalls  int32
 	lastSetMu sync.Mutex
 	lastSet   string
 }
@@ -63,6 +66,14 @@ func (c *dashboardCacheStub) SetDashboardStats(ctx context.Context, data string,
 	return nil
 }
 
+func (c *dashboardCacheStub) DeleteDashboardStats(ctx context.Context) error {
+	atomic.AddInt32(&c.delCalls, 1)
+	if c.del != nil {
+		return c.del(ctx)
+	}
+	return nil
+}
+
 func (c *dashboardCacheStub) readLastEntry(t *testing.T) dashboardStatsCacheEntry {
 	t.Helper()
 	c.lastSetMu.Lock()
@@ -187,3 +198,36 @@ func TestDashboardService_CacheHitStale_TriggersAsyncRefresh(t *testing.T) {
 		return atomic.LoadInt32(&cache.setCalls) >= 1
 	}, 1*time.Second, 10*time.Millisecond)
 }
+
+func TestDashboardService_CacheParseError_EvictsAndRefetches(t *testing.T) {
+	cache := &dashboardCacheStub{
+		get: func(ctx context.Context) (string, error) {
+			return "not-json", nil
+		},
+	}
+	stats := &usagestats.DashboardStats{TotalUsers: 9}
+	repo := &usageRepoStub{stats: stats}
+	cfg := &config.Config{Dashboard: config.DashboardCacheConfig{Enabled: true}}
+	svc := NewDashboardService(repo, cache, cfg)
+
+	got, err := svc.GetDashboardStats(context.Background())
+	require.NoError(t, err)
+	require.Equal(t, stats, got)
+	require.Equal(t, int32(1), atomic.LoadInt32(&cache.delCalls))
+	require.Equal(t, int32(1), atomic.LoadInt32(&repo.calls))
+}
+
+func TestDashboardService_CacheParseError_RepoFailure(t *testing.T) {
+	cache := &dashboardCacheStub{
+		get: func(ctx context.Context) (string, error) {
+			return "not-json", nil
+		},
+	}
+	repo := &usageRepoStub{err: errors.New("db down")}
+	cfg := &config.Config{Dashboard: config.DashboardCacheConfig{Enabled: true}}
+	svc := NewDashboardService(repo, cache, cfg)
+
+	_, err := svc.GetDashboardStats(context.Background())
+	require.Error(t, err)
+	require.Equal(t, int32(1), atomic.LoadInt32(&cache.delCalls))
+}