feat: 实现并发安全的 ULID trace ID 生成器

backend/internal/trace/id.go

@@ -0,0 +1,22 @@
+package trace
+
+import (
+	cryptorand "crypto/rand"
+	"sync"
+	"time"
+
+	"github.com/oklog/ulid/v2"
+)
+
+var entropyPool = sync.Pool{
+	New: func() interface{} {
+		return ulid.Monotonic(cryptorand.Reader, 0)
+	},
+}
+
+// GenerateTraceID 生成并发安全的 ULID trace ID
+func GenerateTraceID() string {
+	entropy := entropyPool.Get().(*ulid.MonotonicEntropy)
+	defer entropyPool.Put(entropy)
+	return ulid.MustNew(ulid.Timestamp(time.Now()), entropy).String()
+}