refactor: plugin code structure

plugin/go/interface.go

@@ -0,0 +1,14 @@
+package pluginInternal
+
+// FuncCaller is the interface that we're exposing as a plugin.
+type FuncCaller interface {
+	GetNames() ([]string, error)                                    // get all plugin function names list
+	Call(funcName string, args ...interface{}) (interface{}, error) // call plugin function
+}
+
+type IPlugin interface {
+	Init(path string) error                                         // init plugin
+	Has(funcName string) bool                                       // check if plugin has function
+	Call(funcName string, args ...interface{}) (interface{}, error) // call function
+	Quit() error                                                    // quit plugin
+}