Golang 微服务教程（二）

package main

import (
	pb "shippy/consignment-service/proto/consignment"
	"context"
	"log"
	"github.com/micro/go-micro"
)

//
// 仓库接口
//
type IRepository interface {
	Create(consignment *pb.Consignment) (*pb.Consignment, error) // 存放新货物
	GetAll() []*pb.Consignment                                   // 获取仓库中所有的货物
}

//
// 我们存放多批货物的仓库，实现了 IRepository 接口
//
type Repository struct {
	consignments []*pb.Consignment
}

func (repo *Repository) Create(consignment *pb.Consignment) (*pb.Consignment, error) {
	repo.consignments = append(repo.consignments, consignment)
	return consignment, nil
}

func (repo *Repository) GetAll() []*pb.Consignment {
	return repo.consignments
}

//
// 定义微服务
//
type service struct {
	repo Repository
}

//
// 实现 consignment.pb.go 中的 ShippingServiceHandler 接口
// 使 service 作为 gRPC 的服务端
//
// 托运新的货物
// func (s *service) CreateConsignment(ctx context.Context, req *pb.Consignment) (*pb.Response, error) {
func (s *service) CreateConsignment(ctx context.Context, req *pb.Consignment, resp *pb.Response) error {
	// 接收承运的货物
	consignment, err := s.repo.Create(req)
	if err != nil {
		return err
	}
	resp = &pb.Response{Created: true, Consignment: consignment}
	return nil
}

// 获取目前所有托运的货物
// func (s *service) GetConsignments(ctx context.Context, req *pb.GetRequest) (*pb.Response, error) {
func (s *service) GetConsignments(ctx context.Context, req *pb.GetRequest, resp *pb.Response) error {
	allConsignments := s.repo.GetAll()
	resp = &pb.Response{Consignments: allConsignments}
	return nil
}

func main() {
	server := micro.NewService(
		// 必须和 consignment.proto 中的 package 一致
		micro.Name("go.micro.srv.consignment"),
		micro.Version("latest"),
	)

	// 解析命令行参数
	server.Init()
	repo := Repository{}
	pb.RegisterShippingServiceHandler(server.Server(), &service{repo})

	if err := server.Run(); err != nil {
		log.Fatalf("failed to serve: %v", err)
	}
}

func main() {
	cmd.Init()
	// 创建微服务的客户端，简化了手动 Dial 连接服务端的步骤
	client := pb.NewShippingServiceClient("go.micro.srv.consignment", microclient.DefaultClient)
	...
}

package main

import (
	pb "shippy/vessel-service/proto/vessel"
	"github.com/pkg/errors"
	"context"
	"github.com/micro/go-micro"
	"log"
)

type Repository interface {
	FindAvailable(*pb.Specification) (*pb.Vessel, error)
}

type VesselRepository struct {
	vessels []*pb.Vessel
}

// 接口实现
func (repo *VesselRepository) FindAvailable(spec *pb.Specification) (*pb.Vessel, error) {
	// 选择最近一条容量、载重都符合的货轮
	for _, v := range repo.vessels {
		if v.Capacity >= spec.Capacity && v.MaxWeight >= spec.MaxWeight {
			return v, nil
		}
	}
	return nil, errors.New("No vessel can't be use")
}

// 定义货船服务
type service struct {
	repo Repository
}

// 实现服务端
func (s *service) FindAvailable(ctx context.Context, spec *pb.Specification, resp *pb.Response) error {
	// 调用内部方法查找
	v, err := s.repo.FindAvailable(spec)
	if err != nil {
		return err
	}
	resp.Vessel = v
	return nil
}

func main() {
	// 停留在港口的货船，先写死
	vessels := []*pb.Vessel{
		{Id: "vessel001", Name: "Boaty McBoatface", MaxWeight: 200000, Capacity: 500},
	}
	repo := &VesselRepository{vessels}
	server := micro.NewService(
		micro.Name("go.micro.srv.vessel"),
		micro.Version("latest"),
	)
	server.Init()

	// 将实现服务端的 API 注册到服务端
	pb.RegisterVesselServiceHandler(server.Server(), &service{repo})

	if err := server.Run(); err != nil {
		log.Fatalf("failed to serve: %v", err)
	}
}

// consignent-service/main.go
package main

import (...)


// 定义微服务
type service struct {
	repo Repository
	// consignment-service 作为客户端调用 vessel-service 的函数
	vesselClient vesselPb.VesselServiceClient
}

// 实现 consignment.pb.go 中的 ShippingServiceHandler 接口，使 service 作为 gRPC 的服务端
func (s *service) CreateConsignment(ctx context.Context, req *pb.Consignment, resp *pb.Response) error {

	// 检查是否有适合的货轮
	vReq := &vesselPb.Specification{
		Capacity:  int32(len(req.Containers)),
		MaxWeight: req.Weight,
	}
	vResp, err := s.vesselClient.FindAvailable(context.Background(), vReq)
	if err != nil {
		return err
	}

	// 货物被承运
	log.Printf("found vessel: %s\n", vResp.Vessel.Name)
	req.VesselId = vResp.Vessel.Id
	consignment, err := s.repo.Create(req)
	if err != nil {
		return err
	}
	resp.Created = true
	resp.Consignment = consignment
	return nil
}

// ...

func main() {
	// ...

	// 解析命令行参数
	server.Init()
	repo := Repository{}
	// 作为 vessel-service 的客户端
	vClient := vesselPb.NewVesselServiceClient("go.micro.srv.vessel", server.Client())
	pb.RegisterShippingServiceHandler(server.Server(), &service{repo, vClient})

	if err := server.Run(); err != nil {
		log.Fatalf("failed to serve: %v", err)
	}
}