options: improve options handling

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

options/options.go

@@ -0,0 +1,222 @@
+package options
+
+import (
+	"reflect"
+	"strings"
+	"time"
+
+	"github.com/spf13/cast"
+	mreflect "go.unistack.org/micro/v3/util/reflect"
+)
+
+// Options interface must be used by all options
+type Validator interface {
+	// Validate returns nil, if all options are correct,
+	// otherwise returns an error explaining the mistake
+	Validate() error
+}
+
+// Option func signature
+type Option func(interface{}) error
+
+// Apply assign options to struct src
+func Apply(src interface{}, opts ...Option) error {
+	for _, opt := range opts {
+		if err := opt(src); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+// SetValueByPath set src struct field to val dst via path
+func SetValueByPath(src interface{}, dst interface{}, path string) error {
+	var err error
+
+	switch v := dst.(type) {
+	case []interface{}:
+		if len(v) == 1 {
+			dst = v[0]
+		}
+	}
+
+	var sv reflect.Value
+	switch t := src.(type) {
+	case reflect.Value:
+		sv = t
+	default:
+		sv = reflect.ValueOf(src)
+	}
+
+	parts := strings.Split(path, ".")
+
+	for _, p := range parts {
+
+		if sv.Kind() == reflect.Ptr {
+			sv = sv.Elem()
+		}
+		if sv.Kind() != reflect.Struct {
+			return mreflect.ErrInvalidStruct
+		}
+
+		typ := sv.Type()
+		for idx := 0; idx < typ.NumField(); idx++ {
+			fld := typ.Field(idx)
+			val := sv.Field(idx)
+
+			/*
+				if len(fld.PkgPath) != 0 {
+					continue
+				}
+			*/
+
+			if fld.Anonymous {
+				if len(parts) == 1 && val.Kind() == reflect.Struct {
+					if err = SetValueByPath(val, dst, p); err != nil {
+						return err
+					}
+				}
+			}
+
+			if fld.Name != p && !strings.EqualFold(strings.ToLower(fld.Name), strings.ToLower(p)) {
+				continue
+			}
+
+			switch val.Interface().(type) {
+			case []time.Duration:
+				dst, err = cast.ToDurationSliceE(dst)
+				if err != nil {
+					return err
+				}
+				reflect.Copy(val, reflect.ValueOf(dst))
+				return nil
+			case time.Duration:
+				dst, err = cast.ToDurationE(dst)
+				if err != nil {
+					return err
+				}
+				val.Set(reflect.ValueOf(dst))
+				return nil
+			case time.Time:
+				dst, err = cast.ToTimeE(dst)
+				if err != nil {
+					return err
+				}
+				val.Set(reflect.ValueOf(dst))
+				return nil
+			}
+
+			switch val.Kind() {
+			case reflect.Map:
+				if val.IsZero() {
+					val.Set(reflect.MakeMap(val.Type()))
+				}
+
+				return setMap(val.Interface(), dst)
+			case reflect.Array, reflect.Slice:
+				switch val.Type().Elem().Kind() {
+				case reflect.Bool:
+					dst, err = cast.ToBoolSliceE(dst)
+				case reflect.String:
+					dst, err = cast.ToStringSliceE(dst)
+				case reflect.Float32:
+					dst, err = toFloat32SliceE(dst)
+				case reflect.Float64:
+					dst, err = toFloat64SliceE(dst)
+				case reflect.Int8:
+					dst, err = toInt8SliceE(dst)
+				case reflect.Int:
+					dst, err = cast.ToIntSliceE(dst)
+				case reflect.Int16:
+					dst, err = toInt16SliceE(dst)
+				case reflect.Int32:
+					dst, err = toInt32SliceE(dst)
+				case reflect.Int64:
+					dst, err = toInt64SliceE(dst)
+				case reflect.Uint8:
+					dst, err = toUint8SliceE(dst)
+				case reflect.Uint:
+					dst, err = toUintSliceE(dst)
+				case reflect.Uint16:
+					dst, err = toUint16SliceE(dst)
+				case reflect.Uint32:
+					dst, err = toUint32SliceE(dst)
+				case reflect.Uint64:
+					dst, err = toUint64SliceE(dst)
+				}
+				if err != nil {
+					return err
+				}
+				if val.Kind() == reflect.Slice {
+					val.Set(reflect.ValueOf(dst))
+				} else {
+					reflect.Copy(val, reflect.ValueOf(dst))
+				}
+				return nil
+			case reflect.Float32:
+				dst, err = toFloat32SliceE(dst)
+			case reflect.Float64:
+				dst, err = toFloat64SliceE(dst)
+			case reflect.Bool:
+				dst, err = cast.ToBoolE(dst)
+			case reflect.String:
+				dst, err = cast.ToStringE(dst)
+			case reflect.Int8:
+				dst, err = cast.ToInt8E(dst)
+			case reflect.Int:
+				dst, err = cast.ToIntE(dst)
+			case reflect.Int16:
+				dst, err = cast.ToInt16E(dst)
+			case reflect.Int32:
+				dst, err = cast.ToInt32E(dst)
+			case reflect.Int64:
+				dst, err = cast.ToInt64E(dst)
+			case reflect.Uint8:
+				dst, err = cast.ToUint8E(dst)
+			case reflect.Uint:
+				dst, err = cast.ToUintE(dst)
+			case reflect.Uint16:
+				dst, err = cast.ToUint16E(dst)
+			case reflect.Uint32:
+				dst, err = cast.ToUint32E(dst)
+			case reflect.Uint64:
+				dst, err = cast.ToUint64E(dst)
+			default:
+			}
+			if err != nil {
+				return err
+			}
+			val.Set(reflect.ValueOf(dst))
+		}
+	}
+
+	return nil
+}
+
+// NewOption create new option with name
+func NewOption(name string) func(...interface{}) Option {
+	return func(dst ...interface{}) Option {
+		return func(src interface{}) error {
+			return SetValueByPath(src, dst, name)
+		}
+	}
+}
+
+var (
+	Address   = NewOption("Address")
+	Name      = NewOption("Name")
+	Broker    = NewOption("Broker")
+	Logger    = NewOption("Logger")
+	Meter     = NewOption("Meter")
+	Tracer    = NewOption("Tracer")
+	Store     = NewOption("Store")
+	Register  = NewOption("Register")
+	Router    = NewOption("Router")
+	Codec     = NewOption("Codec")
+	Codecs    = NewOption("Codecs")
+	Client    = NewOption("Client")
+	Context   = NewOption("Context")
+	TLSConfig = NewOption("TLSConfig")
+	Metadata  = NewOption("Metadata")
+	Timeout   = NewOption("Timeout")
+)