init

pkg/conf/config.go

@@ -0,0 +1,28 @@
+package conf
+
+import (
+	"log"
+	"os"
+
+	"gopkg.in/yaml.v3"
+)
+
+func MustLoad(file string, v any) {
+	if err := Load(file, v); err != nil {
+		log.Fatalf("error: config file %s, %s", file, err.Error())
+	}
+}
+
+func Load(file string, v any) error {
+	setDefaults(v)
+	content, err := os.ReadFile(file)
+	if err != nil {
+		return err
+	}
+
+	// Unmarshal the YAML content directly into the target structure
+	if err := yaml.Unmarshal(content, v); err != nil {
+		return err
+	}
+	return nil
+}

pkg/conf/config_test.go

@@ -0,0 +1,18 @@
+package conf
+
+import "testing"
+
+type Server struct {
+	Host string `yaml:"Host" default:"localhost"`
+	Port int    `yaml:"Port" default:"8080"`
+}
+
+type Config struct {
+	Server Server `yaml:"Server"`
+}
+
+func TestConfigLoad(t *testing.T) {
+	var c Config
+	MustLoad("./config_test.yaml", &c)
+	t.Logf("config: %+v", c)
+}

pkg/conf/config_test.yaml

@@ -0,0 +1,3 @@
+Server:
+  Port: 9999
+  Host: 0.0.0.0

pkg/conf/default.go

@@ -0,0 +1,63 @@
+package conf
+
+import (
+	"fmt"
+	"reflect"
+)
+
+func setDefaults(v any) {
+	//  Get the element of the pointer
+	val := reflect.ValueOf(v).Elem()
+	setDefaultsRecursive(val)
+}
+func setDefaultsRecursive(v reflect.Value) {
+	if v.Kind() != reflect.Struct {
+		return
+	}
+	typ := v.Type()
+	for i := 0; i < v.NumField(); i++ {
+		field := v.Field(i)
+		fieldType := typ.Field(i)
+		// if the field is a struct, set recursively
+		if field.Kind() == reflect.Struct {
+			setDefaultsRecursive(field)
+		}
+
+		// if the field is zero value and has default tag, set the default value
+		if isZero(field) {
+			defaultValue := fieldType.Tag.Get("default")
+			if defaultValue != "" {
+				// set the value for the field using reflection
+				field.Set(reflect.ValueOf(parseDefaultValue(field.Kind(), defaultValue)))
+			}
+		}
+	}
+}
+func isZero(v reflect.Value) bool {
+	return reflect.DeepEqual(v.Interface(), reflect.Zero(v.Type()).Interface())
+}
+func parseDefaultValue(kind reflect.Kind, defaultValue string) any {
+	switch kind {
+	case reflect.String:
+		return defaultValue
+	case reflect.Int:
+		var i int
+		_, _ = fmt.Sscanf(defaultValue, "%d", &i)
+		return i
+	case reflect.Int64:
+		var i int64
+		_, _ = fmt.Sscanf(defaultValue, "%d", &i)
+		return i
+	case reflect.Bool:
+		var b bool
+		_, _ = fmt.Sscanf(defaultValue, "%t", &b)
+		return b
+	case reflect.Uint32:
+		var i uint32
+		_, _ = fmt.Sscanf(defaultValue, "%d", &i)
+		return i
+	default:
+		fmt.Printf("类型 %v 没有处理, 值为: %v \n", kind, defaultValue)
+		panic("unhandled default case")
+	}
+}