feat(idempotency): 为关键写接口接入幂等并完善并发容错

backend/internal/service/idempotency_cleanup_service.go

@@ -0,0 +1,91 @@
+package service
+
+import (
+	"context"
+	"sync"
+	"time"
+
+	"github.com/Wei-Shaw/sub2api/internal/config"
+	"github.com/Wei-Shaw/sub2api/internal/pkg/logger"
+)
+
+// IdempotencyCleanupService 定期清理已过期的幂等记录，避免表无限增长。
+type IdempotencyCleanupService struct {
+	repo     IdempotencyRepository
+	interval time.Duration
+	batch    int
+
+	startOnce sync.Once
+	stopOnce  sync.Once
+	stopCh    chan struct{}
+}
+
+func NewIdempotencyCleanupService(repo IdempotencyRepository, cfg *config.Config) *IdempotencyCleanupService {
+	interval := 60 * time.Second
+	batch := 500
+	if cfg != nil {
+		if cfg.Idempotency.CleanupIntervalSeconds > 0 {
+			interval = time.Duration(cfg.Idempotency.CleanupIntervalSeconds) * time.Second
+		}
+		if cfg.Idempotency.CleanupBatchSize > 0 {
+			batch = cfg.Idempotency.CleanupBatchSize
+		}
+	}
+	return &IdempotencyCleanupService{
+		repo:     repo,
+		interval: interval,
+		batch:    batch,
+		stopCh:   make(chan struct{}),
+	}
+}
+
+func (s *IdempotencyCleanupService) Start() {
+	if s == nil || s.repo == nil {
+		return
+	}
+	s.startOnce.Do(func() {
+		logger.LegacyPrintf("service.idempotency_cleanup", "[IdempotencyCleanup] started interval=%s batch=%d", s.interval, s.batch)
+		go s.runLoop()
+	})
+}
+
+func (s *IdempotencyCleanupService) Stop() {
+	if s == nil {
+		return
+	}
+	s.stopOnce.Do(func() {
+		close(s.stopCh)
+		logger.LegacyPrintf("service.idempotency_cleanup", "[IdempotencyCleanup] stopped")
+	})
+}
+
+func (s *IdempotencyCleanupService) runLoop() {
+	ticker := time.NewTicker(s.interval)
+	defer ticker.Stop()
+
+	// 启动后先清理一轮，防止重启后积压。
+	s.cleanupOnce()
+
+	for {
+		select {
+		case <-ticker.C:
+			s.cleanupOnce()
+		case <-s.stopCh:
+			return
+		}
+	}
+}
+
+func (s *IdempotencyCleanupService) cleanupOnce() {
+	ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
+	defer cancel()
+
+	deleted, err := s.repo.DeleteExpired(ctx, time.Now(), s.batch)
+	if err != nil {
+		logger.LegacyPrintf("service.idempotency_cleanup", "[IdempotencyCleanup] cleanup failed err=%v", err)
+		return
+	}
+	if deleted > 0 {
+		logger.LegacyPrintf("service.idempotency_cleanup", "[IdempotencyCleanup] cleaned expired records count=%d", deleted)
+	}
+}