Bus experiment

pkg/bus/bus.go

@@ -0,0 +1,47 @@
+package bus
+
+import (
+	"errors"
+	"fmt"
+	"reflect"
+)
+
+type QueryHandler interface{}
+type Query interface{}
+
+var (
+	handlerIndex map[string]QueryHandler
+)
+
+func InitBus() {
+	handlerIndex = make(map[string]QueryHandler)
+}
+
+func SendQuery(query interface{}) error {
+	var queryName = reflect.TypeOf(query).Elem().Name()
+	fmt.Printf("sending query for type: %v\n", queryName)
+
+	var handler = handlerIndex[queryName]
+	if handler == nil {
+		return errors.New("handler not found")
+
+	}
+	var params = make([]reflect.Value, 1)
+	params[0] = reflect.ValueOf(query)
+
+	ret := reflect.ValueOf(handler).Call(params)
+	err := ret[0].Interface()
+	if err == nil {
+		return nil
+	} else {
+		return err.(error)
+	}
+}
+
+func AddQueryHandler(handler QueryHandler) {
+	handlerType := reflect.TypeOf(handler)
+	queryTypeName := handlerType.In(0).Elem().Name()
+	fmt.Printf("QueryType %v\n", queryTypeName)
+	handlerIndex[queryTypeName] = handler
+	//fmt.Printf("Adding handler for type: %v\n", queryTypeName)
+}

pkg/bus/bus_test.go

@@ -0,0 +1,45 @@
+package bus
+
+import (
+	"errors"
+	"testing"
+)
+
+type TestQuery struct {
+	Id   int64
+	Resp string
+}
+
+func TestHandlerReturnsError(t *testing.T) {
+	InitBus()
+
+	AddQueryHandler(func(query *TestQuery) error {
+		return errors.New("handler error")
+	})
+
+	err := SendQuery(&TestQuery{})
+
+	if err == nil {
+		t.Fatal("Send query failed %v", err)
+	} else {
+		t.Log("Handler error received ok")
+	}
+}
+
+func TestHandlerReturn(t *testing.T) {
+	InitBus()
+
+	AddQueryHandler(func(q *TestQuery) error {
+		q.Resp = "hello from handler"
+		return nil
+	})
+
+	query := &TestQuery{}
+	err := SendQuery(query)
+
+	if err != nil {
+		t.Fatal("Send query failed %v", err)
+	} else if query.Resp != "hello from handler" {
+		t.Fatal("Failed to get response from handler")
+	}
+}