implemented fist banktransfer version

src/banktransfer/main.go

 package main
 
+import (
+	"fmt"
+	"net"
+	"os"
+
+	log "github.com/sirupsen/logrus"
+	"gitlab.reutlingen-university.de/albrecht/myaktion-go/src/banktransfer/grpc/banktransfer"
+	"gitlab.reutlingen-university.de/albrecht/myaktion-go/src/banktransfer/service"
+	"google.golang.org/grpc"
+)
+
+func init() {
+	log.SetFormatter(&log.TextFormatter{})
+	log.SetReportCaller(true)
+	level, err := log.ParseLevel(os.Getenv("LOG_LEVEL"))
+	if err != nil {
+		log.Info("Log level not specified, set default to: INFO")
+		log.SetLevel(log.InfoLevel)
+		return
+	}
+	log.SetLevel(level)
+}
+
+var grpcPort = 9111
+
 func main() {
-	//test
+	log.Info("Starting Banktransfer server")
+	lis, err := net.Listen("tcp", fmt.Sprintf(":%d", grpcPort))
+	if err != nil {
+		log.Fatalf("failed to listen on grpc port %d: %v", grpcPort, err)
+	}
+	grpcServer := grpc.NewServer()
+	banktransfer.RegisterBankTransferServer(grpcServer, service.NewBankTransferService())
+	if err := grpcServer.Serve(lis); err != nil {
+		log.Fatalf("failed to serve: %v", err)
+	}
 }

src/banktransfer/service/banktransfer.go

@@ -2,6 +2,7 @@ package service
 
 import (
 	"context"
+	"time"
 
 	log "github.com/sirupsen/logrus"
 	"gitlab.reutlingen-university.de/albrecht/myaktion-go/src/banktransfer/grpc/banktransfer"
@@ -20,3 +21,38 @@ func (s *BankTransferService) TransferMoney(_ context.Context, transaction *bank
 	log.Infof("Received transaction: %v", transaction)
 	return &emptypb.Empty{}, nil
 }
+
+func (s *BankTransferService) ProcessTransactions(stream banktransfer.BankTransfer_ProcessTransactionsServer) error {
+	ticker := time.NewTicker(2 * time.Second)
+	defer ticker.Stop()
+	return func() error {
+		for {
+			select {
+			case <-stream.Context().Done():
+				log.Info("Watching transactions cancelled from the client side")
+				return nil
+			case <-ticker.C:
+				transaction := &banktransfer.Transaction{Id: s.counter, Amount: 20}
+				entry := log.WithField("transaction", transaction)
+				entry.Info("Sending transaction")
+				if err := stream.Send(transaction); err != nil {
+					entry.WithError(err).Error("Error sending transaction")
+					return err
+				}
+				entry.Info("Transaction sent. Waiting for processing response")
+				response, err := stream.Recv()
+				if err != nil {
+					entry.WithError(err).Error("Error receiving processing response")
+					return err
+				}
+				if response.Id != s.counter {
+					// NOTE: this is just a guard and not happening as transaction is local per connection
+					entry.Error("Received processing response of a different transaction")
+				} else {
+					entry.Info("Processing response received")
+					s.counter++
+				}
+			}
+		}
+	}()
+}