config: export method to init new empty struct

Signed-off-by: Vasiliy Tolstov <v.tolstov@unistack.org>

config/reflect.go

@@ -1,6 +1,8 @@
 package config
 
-import "reflect"
+import (
+	"reflect"
+)
 
 func IsEmpty(v reflect.Value) bool {
 	switch v.Kind() {
@@ -26,3 +28,19 @@ func IsEmpty(v reflect.Value) bool {
 	}
 	return false
 }
+
+func Zero(src interface{}) (interface{}, error) {
+	sv := reflect.ValueOf(src)
+
+	if sv.Kind() == reflect.Ptr {
+		sv = sv.Elem()
+	}
+
+	if sv.Kind() == reflect.Invalid {
+		return nil, ErrInvalidStruct
+	}
+
+	dst := reflect.New(sv.Type())
+
+	return dst.Interface(), nil
+}

config/reflect_test.go

@@ -0,0 +1,26 @@
+package config_test
+
+import (
+	"testing"
+
+	"github.com/unistack-org/micro/v3/config"
+)
+
+type Config struct {
+	Value     string
+	SubConfig *SubConfig
+	Config    *Config
+}
+
+type SubConfig struct {
+	Value string
+}
+
+func TestReflect(t *testing.T) {
+	cfg1 := &Config{Value: "cfg1", Config: &Config{Value: "cfg1_1"}, SubConfig: &SubConfig{Value: "cfg1"}}
+	cfg2, err := config.Clone(cfg1)
+	if err != nil {
+		t.Fatal(err)
+	}
+	t.Logf("dst: %#+v\n", cfg2)
+}