return error when uuid is not enough

pkg/uuid/internal_generator.go

@@ -51,6 +51,11 @@ func NewInternalUuidGenerator(config *settings.Config) (*InternalUuidGenerator,
 // GenerateUuid generates a new uuid
 func (u *InternalUuidGenerator) GenerateUuid(idType UuidType) int64 {
 	uuids := u.GenerateUuids(idType, 1)
+
+	if len(uuids) < 1 {
+		return 0
+	}
+
 	return uuids[0]
 }
 
@@ -89,6 +94,12 @@ func (u *InternalUuidGenerator) GenerateUuids(idType UuidType, count uint8) []in
 
 	for i := 0; i < int(count); i++ {
 		seqId := (newFirstSeqId + uint64(i)) & seqNumberIdMask
+
+		// the internal uuid generator can only generate 524,287 ids per second for specified type
+		if seqId > internalUuidSeqIdMask {
+			return nil
+		}
+
 		uuids[i] = u.assembleUuid(unixTime, uuidType, seqId)
 	}
 

pkg/uuid/internal_generator_test.go

@@ -374,3 +374,25 @@ func TestGenerateUuids_1000000TimesConcurrent(t *testing.T) {
 
 	waitGroup.Wait()
 }
+
+func TestGenerateUuid_Over524287Times(t *testing.T) {
+	generator, _ := NewInternalUuidGenerator(&settings.Config{UuidServerId: 1})
+	onceGenerateCount := uint8(255)
+	generationStartUnixTime := time.Now().Unix()
+
+	for i := 0; i < 2057; i++ { // 2056*255=524280, 2057*255=524,535 (only can generates 524,287 uuids per second)
+		uuids := generator.GenerateUuids(UUID_TYPE_USER, onceGenerateCount)
+
+		if i < 2056 {
+			if len(uuids) < int(onceGenerateCount) {
+				assert.Fail(t, fmt.Sprintf("%d uuids should be generated", onceGenerateCount))
+			}
+		} else {
+			generationEndUnixTime := time.Now().Unix()
+
+			if generationStartUnixTime == generationEndUnixTime && len(uuids) > 0 {
+				assert.Fail(t, fmt.Sprintf("uuids should not be generated because there are too many uuids in one second"))
+			}
+		}
+	}
+}