feature: add a mongo registry option to convert type easier. (#3780)

Co-authored-by: Kevin Wan <wanjunfeng@gmail.com>

core/stores/mon/options_test.go

@@ -1,10 +1,14 @@
 package mon
 
 import (
+	"fmt"
+	"reflect"
 	"testing"
 	"time"
 
 	"github.com/stretchr/testify/assert"
+	"go.mongodb.org/mongo-driver/bson/bsoncodec"
+	"go.mongodb.org/mongo-driver/bson/bsonrw"
 	mopt "go.mongodb.org/mongo-driver/mongo/options"
 )
 
@@ -51,3 +55,56 @@ func TestDisableInfoLog(t *testing.T) {
 	assert.False(t, logMon.True())
 	assert.True(t, logSlowMon.True())
 }
+
+func TestWithRegistryForTimestampRegisterType(t *testing.T) {
+	opts := mopt.Client()
+
+	// mongoDateTimeEncoder allow user convert time.Time to primitive.DateTime.
+	var mongoDateTimeEncoder bsoncodec.ValueEncoderFunc = func(ect bsoncodec.EncodeContext, w bsonrw.ValueWriter, value reflect.Value) error {
+		// Use reflect, determine if it can be converted to time.Time.
+		dec, ok := value.Interface().(time.Time)
+		if !ok {
+			return fmt.Errorf("value %v to encode is not of type time.Time", value)
+		}
+		return w.WriteDateTime(dec.Unix())
+	}
+
+	// mongoDateTimeEncoder allow user convert primitive.DateTime to time.Time.
+	var mongoDateTimeDecoder bsoncodec.ValueDecoderFunc = func(ect bsoncodec.DecodeContext, r bsonrw.ValueReader, value reflect.Value) error {
+		primTime, err := r.ReadDateTime()
+		if err != nil {
+			return fmt.Errorf("error reading primitive.DateTime from ValueReader: %v", err)
+		}
+		value.Set(reflect.ValueOf(time.Unix(primTime, 0)))
+		return nil
+	}
+
+	registerType := []RegisterType{
+		{
+			ValueType: reflect.TypeOf(time.Time{}),
+			Encoder:   mongoDateTimeEncoder,
+			Decoder:   mongoDateTimeDecoder,
+		},
+	}
+	WithRegistry(registerType...)(opts)
+
+	for _, v := range registerType {
+		// Validate Encoder
+		enc, err := opts.Registry.LookupEncoder(v.ValueType)
+		if err != nil {
+			t.Fatal(err)
+		}
+		if assert.ObjectsAreEqual(v.Encoder, enc) {
+			t.Errorf("Encoder got from Registry: %v, but want: %v", enc, v.Encoder)
+		}
+
+		// Validate Decoder
+		dec, err := opts.Registry.LookupDecoder(v.ValueType)
+		if err != nil {
+			t.Fatal(err)
+		}
+		if assert.ObjectsAreEqual(v.Decoder, dec) {
+			t.Errorf("Decoder got from Registry: %v, but want: %v", dec, v.Decoder)
+		}
+	}
+}