manhdaovan · November 1, 2019 14:58 · Nov 1, 2019
diff --git a/unique_id_generator.go b/unique_id_generator.go
@@ -0,0 +1,35 @@
+type sequenceIDGenerator struct {
+	idMgrClient IDManagerClient // client for getting IDPrefix
+	preGenerateIDs chan string // pre-generated ids
+}
+
+// Pre-generate id and send to channel.
+// This method should be called once and only once when init generator
+func (g *sequenceIDGenerator) preGenIDs() {
+	var idBase, id string
+	var seq uint64
+
+	for {
+		if idBase == "" || seq == 0 { // first call or over max uint 64
+			idBase = g.idMgrClient.GetNewIDPrefix("ServiceA")
+		}
+		id = fmt.Sprintf("%s-%d", idBase, strconv.FormatUint(seq, 32))
+		g.preGenerateIDs <- id
+		seq++
+	}
+}
+
+// NewSequenceIDGenerator returns new id generator
+func NewSequenceIDGenerator(imc IDManagerClient) *sequenceIDGenerator {
+	g := &sequenceIDGenerator{
+		idMgrClient: imc,
+		preGenerateIDs: make(chan string, 10000),
+	}
+	go g.preGenIDs()
+	return g
+}
+
+// NextID returns next id.
+func (g *sequenceIDGenerator) NextID() string {
+	return <-g.preGenerateIDs
+}