Channel queue example

channel_queue_example.go

//HTTP method
func (s *server) CreateOrderWith(ctx context.Context, creatOrdReq *pb.CreateOrderRequest) (*pb.CreateOrderRequest, error) {
	ordReq := new(OrdReq)
	ordReq.createOrdReq = creatOrdReq
	ordReq.ctx = ctx

	dbSaveChannel <- ordReq

	select {
		case createOrdReq := <-outputChannel:
			return createOrdReq, nil
		case error := <-errorChannel:
			return nil, error
	}
}


type OrdReq struct {
	createOrdReq *pb.CreateOrderRequest
	ctx context.Context
}

var dbSaveChannel chan *OrdReq
var outputChannel chan *pb.CreateOrderRequest
var errorChannel chan error

var db *sqlx.DB

func main() {
	dbSaveChannel = make(chan *OrdReq)
	outputChannel = make(chan *pb.CreateOrderRequest)
	errorChannel = make(chan error)
	go receiveDataFromInputChannel()
}

func receiveDataFromInputChannel() {
	for ordReq := range dbSaveChannel {

		creatOrdReq := ordReq.createOrdReq
		ctx := ordReq.ctx

		tx := db.MustBegin()

		paymentSerial, err := model.StorePayment(tx, creatOrdReq.Payment)
		if err != nil {
			tx.Rollback()
			log.WithFields(log.Fields{"err": err}).Warn("")
			errorChannel <- err
		}

		creatOrdReq.Payment.PaymentId = paymentSerial
		creatOrdReq.Order.PaymentId = paymentSerial

		orderSerial, err := model.StoreOrder(tx, creatOrdReq.Order)
		if err != nil {
			tx.Rollback()
			log.WithFields(log.Fields{"err": err}).Warn("")
			errorChannel <- err
		}
		creatOrdReq.Order.OrderId = orderSerial
		
		contexErr := ctx.Err()
		if contexErr != nil {
			tx.Rollback()
			log.WithFields(log.Fields{"err": contexErr}).Warn("")
			errorChannel <- err
		}

		err = tx.Commit()
		if err != nil {
			log.WithFields(log.Fields{"err": err}).Warn("")
			errorChannel <- err
		}

		log.WithFields(log.Fields{"orderDocument": orderDocument}).Info("")

		outputChannel <- creatOrdReq
	}
}