go get -u google.golang.org/grpc
go get -u github.com/golang/protobuf/protoc-gen-go

// consignment-service/proto/consignment/consignment.proto
syntax = "proto3";

package go.micro.srv.consignment; 

service ShippingService {
  rpc CreateConsignment(Consignment) returns (Response) {}
}

message Consignment {
  string id = 1;
  string description = 2;
  int32 weight = 3;
  repeated Container containers = 4;
  string vessel_id = 5;
}

message Container {
  string id = 1;
  string customer_id = 2;
  string origin = 3;
  string user_id = 4;
}

message Response {
  bool created = 1;
  Consignment consignment = 2;
}

build:
	protoc -I. --go_out=plugins=grpc:$(GOPATH)/src/github.com/ewanvalentine/shipper/consignment-service \
	  proto/consignment/consignment.proto

// consignment-service/main.go
package main

import (
    "log"
    "net"

    // 导入生成的consignment.pb.go文件
    pb "github.com/ewanvalentine/shipper/consignment-service/proto/consignment"
    "golang.org/x/net/context"
    "google.golang.org/grpc"
    "google.golang.org/grpc/reflection"
    )

const (
    port = ":50051"
    )

type IRepository interface {
  Create(*pb.Consignment) (*pb.Consignment, error)
}

// Repository - 模拟一个数据库，我们会在此后使用真正的数据库替代他
type Repository struct {
  consignments []*pb.Consignment
}

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

// service要实现在proto中定义的所有方法。当你不确定时
// 可以去对应的*.pb.go文件里查看需要实现的方法及其定义
type service struct {
  repo IRepository
}

// CreateConsignment - 在proto中，我们只给这个微服务定一个了一个方法
// 就是这个CreateConsignment方法，它接受一个context以及proto中定义的
// Consignment消息，这个Consignment是由gRPC的服务器处理后提供给你的
func (s *service) CreateConsignment(ctx context.Context, req *pb.Consignment) (*pb.Response, error) {

  // 保存我们的consignment
  consignment, err := s.repo.Create(req)
    if err != nil {
      return nil, err
    }

  // 返回的数据也要符合proto中定义的数据结构
  return &pb.Response{Created: true, Consignment: consignment}, nil
}

func main() {

repo := &Repository{}

      // 设置gRPC服务器
      lis, err := net.Listen("tcp", port)
        if err != nil {
          log.Fatalf("failed to listen: %v", err)
        }
s := grpc.NewServer()

     // 在我们的gRPC服务器上注册微服务，这会将我们的代码和*.pb.go中
     // 的各种interface对应起来
     pb.RegisterShippingServiceServer(s, &service{repo})

     // 在gRPC服务器上注册reflection
     reflection.Register(s)
     if err := s.Serve(lis); err != nil {
       log.Fatalf("failed to serve: %v", err)
     }
}

// consignment-cli/cli.go
package main

import (
    "encoding/json"
    "io/ioutil"
    "log"
    "os"

    pb "github.com/ewanvalentine/shipper/consignment-service/proto/consignment"
    "golang.org/x/net/context"
    "google.golang.org/grpc"
    )

const (
    address         = "localhost:50051"
    defaultFilename = "consignment.json"
    )

func parseFile(file string) (*pb.Consignment, error) {
  var consignment *pb.Consignment
    data, err := ioutil.ReadFile(file)
    if err != nil {
      return nil, err
    }
  json.Unmarshal(data, &consignment)
    return consignment, err
}

func main() {
  // Set up a connection to the server.
  conn, err := grpc.Dial(address, grpc.WithInsecure())
    if err != nil {
      log.Fatalf("Did not connect: %v", err)
    }
  defer conn.Close()
    client := pb.NewShippingServiceClient(conn)

    // Contact the server and print out its response.
    file := defaultFilename
    if len(os.Args) > 1 {
      file = os.Args[1]
    }

  consignment, err := parseFile(file)

    if err != nil {
      log.Fatalf("Could not parse file: %v", err)
    }

  r, err := client.CreateConsignment(context.Background(), consignment)
    if err != nil {
      log.Fatalf("Could not greet: %v", err)
    }
  log.Printf("Created: %t", r.Created)
}

{
  "description": "This is a test consignment",
  "weight": 550,
  "containers": [
    { "customer_id": "cust001", "user_id": "user001", "origin": "Manchester, United Kingdom" }
  ],
  "vessel_id": "vessel001"
}

// consignment-service/proto/consignment/consignment.proto
syntax = "proto3";

package go.micro.srv.consignment;

service ShippingService {
  rpc CreateConsignment(Consignment) returns (Response) {}

  // Created a new method
  rpc GetConsignments(GetRequest) returns (Response) {}
}

message Consignment {
  string id = 1;
  string description = 2;
  int32 weight = 3;
  repeated Container containers = 4;
  string vessel_id = 5;
}

message Container {
  string id = 1;
  string customer_id = 2;
  string origin = 3;
  string user_id = 4;
}

// Created a blank get request
message GetRequest {}

message Response {
  bool created = 1;
  Consignment consignment = 2;

  // Added a pluralised consignment to our generic response message
  repeated Consignment consignments = 3;
}

package main

import (
	"log"
	"net"

	// Import the generated protobuf code
	pb "github.com/ewanvalentine/shipper/consignment-service/proto/consignment"
	"golang.org/x/net/context"
	"google.golang.org/grpc"
	"google.golang.org/grpc/reflection"
)

const (
	port = ":50051"
)

type IRepository interface {
	Create(*pb.Consignment) (*pb.Consignment, error)
	GetAll() []*pb.Consignment
}

// Repository - Dummy repository, this simulates the use of a datastore
// of some kind. We'll replace this with a real implementation later on.
type Repository struct {
	consignments []*pb.Consignment
}

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

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

// Service should implement all of the methods to satisfy the service
// we defined in our protobuf definition. You can check the interface
// in the generated code itself for the exact method signatures etc
// to give you a better idea.
type service struct {
	repo IRepository
}

// CreateConsignment - we created just one method on our service,
// which is a create method, which takes a context and a request as an
// argument, these are handled by the gRPC server.
func (s *service) CreateConsignment(ctx context.Context, req *pb.Consignment) (*pb.Response, error) {

	// Save our consignment
	consignment, err := s.repo.Create(req)
	if err != nil {
		return nil, err
	}

	// Return matching the `Response` message we created in our
	// protobuf definition.
	return &pb.Response{Created: true, Consignment: consignment}, nil
}

func (s *service) GetConsignments(ctx context.Context, req *pb.GetRequest) (*pb.Response, error) {
	consignments := s.repo.GetAll()
	return &pb.Response{Consignments: consignments}, nil
}

func main() {

	repo := &Repository{}

	// Set-up our gRPC server.
	lis, err := net.Listen("tcp", port)
	if err != nil {
		log.Fatalf("failed to listen: %v", err)
	}
	s := grpc.NewServer()

	// Register our service with the gRPC server, this will tie our
	// implementation into the auto-generated interface code for our
	// protobuf definition.
	pb.RegisterShippingServiceServer(s, &service{repo})

	// Register reflection service on gRPC server.
	reflection.Register(s)
	if err := s.Serve(lis); err != nil {
		log.Fatalf("failed to serve: %v", err)
	}
}

func main() {
    ... 

	getAll, err := client.GetConsignments(context.Background(), &pb.GetRequest{})
	if err != nil {
		log.Fatalf("Could not list consignments: %v", err)
	}
	for _, v := range getAll.Consignments {
		log.Println(v)
	}
}