allow getting the saga id of the current invoked saga (#168)

Author: Guy Baron

gbus/abstractions.go

@@ -241,6 +241,9 @@ type SagaInvocation interface {
 	ReplyToInitiator(ctx context.Context, message *BusMessage) error
 	//HostingSvc returns the svc name that is executing the service
 	HostingSvc() string
+
+	//SagaID returns the saga id of the currently invoked saga instance
+	SagaID() string
 }
 
 //Serializer is the base interface for all message serializers

gbus/messages.go

@@ -81,6 +81,11 @@ func (bm *BusMessage) SetPayload(payload Message) {
 	bm.Payload = payload
 }
 
+//TargetSaga allows sending the message to a specific Saga instance
+func (bm *BusMessage) TargetSaga(sagaID string) {
+	bm.SagaID = sagaID
+}
+
 //GetTraceLog returns an array of log entires containing all of the message properties
 func (bm *BusMessage) GetTraceLog() (fields []log.Field) {
 	return []log.Field{

gbus/saga/invocation.go

@@ -115,3 +115,7 @@ func (si *sagaInvocation) Routing() (exchange, routingKey string) {
 func (si *sagaInvocation) DeliveryInfo() gbus.DeliveryInfo {
 	return si.decoratedInvocation.DeliveryInfo()
 }
+
+func (si *sagaInvocation) SagaID() string {
+	return si.sagaID
+}