pkg/config: support nested structs

1 files changed, 45 insertions, 7 deletions

diff --git a/pkg/config/config.go b/pkg/config/config.go
index feb031c71..461ebdabc 100644
--- a/pkg/config/config.go
+++ b/pkg/config/config.go
@@ -33,29 +33,67 @@ func load(data []byte, cfg interface{}) error {
 }
 
 func checkUnknownFields(data []byte, typ reflect.Type) error {
-	if typ.Kind() != reflect.Ptr {
+	if typ.Kind() != reflect.Ptr || typ.Elem().Kind() != reflect.Struct {
 		return fmt.Errorf("config type is not pointer to struct")
 	}
-	typ = typ.Elem()
+	return checkUnknownFieldsRec(data, "", typ)
+}
+
+func checkUnknownFieldsRec(data []byte, prefix string, typ reflect.Type) error {
+	if typ.Kind() == reflect.Ptr {
+		typ = typ.Elem()
+	}
 	if typ.Kind() != reflect.Struct {
 		return fmt.Errorf("config type is not pointer to struct")
 	}
-	fields := make(map[string]bool)
+	fields := make(map[string]reflect.Type)
 	for i := 0; i < typ.NumField(); i++ {
 		field := typ.Field(i)
 		if field.Tag.Get("json") == "-" {
 			continue
 		}
-		fields[strings.ToLower(field.Name)] = true
+		fields[strings.ToLower(field.Name)] = field.Type
 	}
 	f := make(map[string]interface{})
 	if err := json.Unmarshal(data, &f); err != nil {
 		return fmt.Errorf("failed to parse config file: %v", err)
 	}
-	for k := range f {
-		if !fields[strings.ToLower(k)] {
-			return fmt.Errorf("unknown field '%v' in config", k)
+	for k, v := range f {
+		field, ok := fields[strings.ToLower(k)]
+		if !ok {
+			return fmt.Errorf("unknown field '%v%v' in config", prefix, k)
+		}
+		if field.Kind() == reflect.Slice &&
+			(field.PkgPath() != "encoding/json" || field.Name() != "RawMessage") {
+			vv := reflect.ValueOf(v)
+			if vv.Type().Kind() != reflect.Slice {
+				return fmt.Errorf("bad json array type '%v%v'", prefix, k)
+			}
+			for i := 0; i < vv.Len(); i++ {
+				e := vv.Index(i).Interface()
+				prefix1 := fmt.Sprintf("%v%v[%v].", prefix, k, i)
+				if err := checkUnknownFieldsStruct(e, prefix1, field.Elem()); err != nil {
+					return err
+				}
+			}
+		}
+		if err := checkUnknownFieldsStruct(v, prefix+k+".", field); err != nil {
+			return err
 		}
 	}
 	return nil
 }
+
+func checkUnknownFieldsStruct(val interface{}, prefix string, typ reflect.Type) error {
+	if typ.Kind() == reflect.Ptr {
+		typ = typ.Elem()
+	}
+	if typ.Kind() != reflect.Struct {
+		return nil
+	}
+	inner, err := json.Marshal(val)
+	if err != nil {
+		return fmt.Errorf("failed to marshal inner struct '%v%v':", prefix, err)
+	}
+	return checkUnknownFieldsRec(inner, prefix, typ)
+}