checkoutservice: add code stubs, TODO implement

Signed-off-by: Ahmet Alp Balkan <ahmetb@google.com>

.gitignore

@@ -1,3 +1,5 @@
+bin/
+pkg/
 .DS_Store
 *.pyc
 *.swp

src/checkoutservice/genproto.sh

@@ -0,0 +1,6 @@
+#!/bin/bash -e
+
+PATH=$PATH:$GOPATH/bin
+protodir=../../pb
+
+protoc --go_out=plugins=grpc:genproto -I $protodir $protodir/demo.proto

src/checkoutservice/main.go

@@ -0,0 +1,70 @@
+package main
+
+import (
+	"context"
+	"fmt"
+	"log"
+	"net"
+	"os"
+
+	pb "./genproto"
+	"google.golang.org/grpc"
+)
+
+const (
+	listenPort = "5000"
+)
+
+type checkoutService struct {
+	productCatalogSvcAddr string
+	cartSvcAddr           string
+	currencySvcAddr       string
+	shippingSvcAddr       string
+	emailSvcAddr          string
+	paymentSvcAddr        string
+}
+
+func main() {
+	port := listenPort
+	if os.Getenv("PORT") != "" {
+		port = os.Getenv("PORT")
+	}
+
+	svc := new(checkoutService)
+	mustMapEnv(&svc.productCatalogSvcAddr, "PRODUCT_CATALOG_SERVICE_ADDR")
+	mustMapEnv(&svc.cartSvcAddr, "CART_SERVICE_ADDR")
+	mustMapEnv(&svc.currencySvcAddr, "CURRENCY_SERVICE_ADDR")
+	mustMapEnv(&svc.shippingSvcAddr, "SHIPPING_SERVICE_ADDR")
+	mustMapEnv(&svc.emailSvcAddr, "EMAIL_SERVICE_ADDR")
+	mustMapEnv(&svc.paymentSvcAddr, "PAYMENT_SERVICE_ADDR")
+
+	log.Printf("starting to listen on tcp/%s", port)
+	lis, err := net.Listen("tcp", fmt.Sprintf(":%s", port))
+	if err != nil {
+		log.Fatal(err)
+	}
+	srv := grpc.NewServer()
+	pb.RegisterCheckoutServiceServer(srv, svc)
+	log.Println("starting to listen on tcp: %q", lis.Addr().String())
+	log.Fatal(srv.Serve(lis))
+}
+
+func mustMapEnv(target *string, envKey string) {
+	v := os.Getenv(envKey)
+	if v == "" {
+		panic(fmt.Sprintf("environment variable %q not set", envKey))
+	}
+	*target = v
+}
+
+func (cs *checkoutService) CreateOrder(ctx context.Context, req *pb.CreateOrderRequest) (*pb.CreateOrderResponse, error) {
+	log.Printf("[CreateOrder] user_id=%q user_currency=%q", req.UserId, req.UserCurrency)
+	resp := new(pb.CreateOrderResponse)
+	return resp, nil
+}
+
+func (cs *checkoutService) PlaceOrder(ctx context.Context, req *pb.PlaceOrderRequest) (*pb.PlaceOrderResponse, error) {
+	log.Printf("[PlaceOrder] user_id=%q user_currency=%q", req.UserId, req.UserCurrency)
+	resp := new(pb.PlaceOrderResponse)
+	return resp, nil
+}