Implement singleton pattern

singleton/singleton.go

@@ -0,0 +1,20 @@
+package singleton
+
+import (
+	"sync"
+)
+
+type Object struct {
+}
+
+var once sync.Once
+var instance *Object
+
+func GetInstance() *Object {
+	// Creates a singleton instance once.
+	once.Do(func() {
+		instance = &singleton{}
+	})
+
+	return instance
+}