Expose Lock Sequence Number

zk/lock.go

@@ -148,3 +148,10 @@ func (l *Lock) Unlock() error {
 	l.seq = 0
 	return nil
 }
+
+// SequenceNumber returns the sequence number generated by zookeeper which is
+// unique to the current lock acquisition. This function should only be called
+// once a lock has been acquired and not after it has been released
+func (l *Lock) SequenceNumber() int {
+	return l.seq
+}

zk/lock_test.go

@@ -23,6 +23,13 @@ func TestLock(t *testing.T) {
 	if err := l.Lock(); err != nil {
 		t.Fatal(err)
 	}
+
+	lockSequenceNumber := l.SequenceNumber()
+	if 0 == lockSequenceNumber {
+		t.Fatal("expected non-zero lock sequence number once " +
+			"initially acquired")
+	}
+
 	if err := l.Unlock(); err != nil {
 		t.Fatal(err)
 	}