Go实战golang中使用gRPC和Protobuf实现高性能api(golang/protobuf、google.golang.org/grpc)

生命不止，继续 go go go !!!

号外号外，插播一条广告，通过博客的uv可以看到周五，程序员是不怎么干活的：

本篇博客，使用gRPC和Protobuf，实现所谓的高性能api。

protobuf

golang中的protobuf大家应该不会很陌生，之前也有博客介绍过：
Go实战–go中使用google/protobuf(The way to go)

Protocol Buffers (a.k.a., protobuf) are Google’s language-neutral, platform-neutral, extensible mechanism for serializing structured data. You can find protobuf’s documentation on the Google Developers site.

获取：

go get -u github.com/golang/protobuf/proto
go get -u github.com/golang/protobuf/protoc-gen-go

Protobuf语法
下面简要介绍Protobuf语法：
参考：https://segmentfault.com/a/1190000007917576
官方：
https://developers.google.com/protocol-buffers/
https://developers.google.com/protocol-buffers/docs/gotutorial

Message定义
一个message类型定义描述了一个请求或相应的消息格式，可以包含多种类型字段。例如定义一个搜索请求的消息格式，每个请求包含查询字符串、页码、每页数目。

syntax = "proto3";
package tutorial;

首行声明使用的protobuf版本为proto3

message Person {
  string name = 1;
  int32 id = 2;  // Unique ID number for this person.
  string email = 3;

  enum PhoneType {
    MOBILE = 0;
    HOME = 1;
    WORK = 2;
  }

  message PhoneNumber {
    string number = 1;
    PhoneType type = 2;
  }

  repeated PhoneNumber phOnes= 4;
}

// Our address book file is just one of these.
message AddressBook {
  repeated Person people = 1;
}

生成

protoc -I=$SRC_DIR --go_out=$DST_DIR $SRC_DIR/addressbook.proto

写消息

book := &pb.AddressBook{}
// ...

// Write the new address book back to disk.
out, err := proto.Marshal(book)
if err != nil {
        log.Fatalln("Failed to encode address book:", err)
}
if err := ioutil.WriteFile(fname, out, 0644); err != nil {
        log.Fatalln("Failed to write address book:", err)
}

读消息

// Read the existing address book.
in, err := ioutil.ReadFile(fname)
if err != nil {
        log.Fatalln("Error reading file:", err)
}
book := &pb.AddressBook{}
if err := proto.Unmarshal(in, book); err != nil {
        log.Fatalln("Failed to parse address book:", err)
}

grpc

golang中的rpc大家也不会陌生，之前也有介绍过奥：
Go实战–go中使用rpc(The way to go)

什么是rpc
RPC是Remote Procedure CallProtocol的缩写，即—远程过程调用协议。

RPC是一个计算机通信协议。该协议允许运行于一台计算机的程序调用另一台计算机的子程序，而程序员无需额外地为这个交互作用编程。如果涉及的软件采用面向对象编程，那么远程过程调用亦可称作远程调用或远程方法调用，信息数据。通过它可以使函数调用模式网络化。在OSI网络通信模型中，RPC跨越了传输层和应用层。RPC使得开发包括网络分布式多程序在内的应用程序更加容易。

net/rpc
Go语言标准库能够自带一个rpc框架还是非常给力的，这可以很大程度的降低写后端网络通信服务的门槛，特别是在大规模的分布式系统中，rpc基本是跨机器通信的标配。rpc能够最大程度屏蔽网络细节，让开发者专注在服务功能的开发上面

什么是grpc
gRPC 是一个高性能、开源、通用的RPC框架，由Google推出，基于HTTP/2协议标准设计开发，默认采用Protocol Buffers数据序列化协议，支持多种开发语言。gRPC提供了一种简单的方法来精确的定义服务，并且为客户端和服务端自动生成可靠的功能库。

在gRPC客户端可以直接调用不同服务器上的远程程序，使用姿势看起来就像调用本地程序一样，很容易去构建分布式应用和服务。和很多RPC系统一样，服务端负责实现定义好的接口并处理客户端的请求，客户端根据接口描述直接调用需要的服务。客户端和服务端可以分别使用gRPC支持的不同语言实现。

grpc-go
github地址：
https://github.com/grpc/grpc-go

Star: 4402

文档地址：
https://godoc.org/google.golang.org/grpc

获取：
go get -u google.golang.org/grpc

应用

文件结构

proto文件
customer.proto

syntax = "proto3";
package customer;


// The Customer service definition.
service Customer {   
  // Get all Customers with filter - A server-to-client streaming RPC.
  rpc GetCustomers(CustomerFilter) returns (stream CustomerRequest) {}
  // Create a new Customer - A simple RPC 
  rpc CreateCustomer (CustomerRequest) returns (CustomerResponse) {}
}

// Request message for creating a new customer
message CustomerRequest {
  int32 id = 1;  // Unique ID number for a Customer.
  string name = 2;
  string email = 3;
  string phOne= 4;

  message Address {
    string street = 1;
    string city = 2;
    string state = 3;
    string zip = 4;
    bool isShippingAddress = 5; 
  }

  repeated Address addresses = 5;
}

message CustomerResponse {
  int32 id = 1;
  bool success = 2;
}
message CustomerFilter {    
  string keyword = 1;
}

生成customer.pb.go

protoc --go_out=plugins=grpc:. customer.proto

// Code generated by protoc-gen-go. DO NOT EDIT.
// source: customer.proto

/*
Package customer is a generated protocol buffer package.

It is generated from these files:
    customer.proto

It has these top-level messages:
    CustomerRequest
    CustomerResponse
    CustomerFilter
*/
package customer

import proto "github.com/golang/protobuf/proto"
import fmt "fmt"
import math "math"

import (
    context "golang.org/x/net/context"
    grpc "google.golang.org/grpc"
)

// Reference imports to suppress errors if they are not otherwise used.
var _ = proto.Marshal
var _ = fmt.Errorf
var _ = math.Inf

// This is a compile-time assertion to ensure that this generated file
// is compatible with the proto package it is being compiled against.
// A compilation error at this line likely means your copy of the
// proto package needs to be updated.
const _ = proto.ProtoPackageIsVersion2 // please upgrade the proto package

// Request message for creating a new customer
type CustomerRequest struct {
    Id        int32                      `protobuf:"varint,1,opt,name=id" json:"id,omitempty"`
    Name      string                     `protobuf:"bytes,2,opt,name=name" json:"name,omitempty"`
    Email     string                     `protobuf:"bytes,3,opt,name=email" json:"email,omitempty"`
    Phone     string                     `protobuf:"bytes,4,opt,name=phone" json:"phone,omitempty"`
    Addresses []*CustomerRequest_Address `protobuf:"bytes,5,rep,name=addresses" json:"addresses,omitempty"`
}

func (m *CustomerRequest) Reset()                    { *m = CustomerRequest{} }
func (m *CustomerRequest) String() string            { return proto.CompactTextString(m) }
func (*CustomerRequest) ProtoMessage()               {}
func (*CustomerRequest) Descriptor() ([]byte, []int) { return fileDescriptor0, []int{0} }

func (m *CustomerRequest) GetId() int32 {
    if m != nil {
        return m.Id
    }
    return 0
}

func (m *CustomerRequest) GetName() string {
    if m != nil {
        return m.Name
    }
    return ""
}

func (m *CustomerRequest) GetEmail() string {
    if m != nil {
        return m.Email
    }
    return ""
}

func (m *CustomerRequest) GetPhone() string {
    if m != nil {
        return m.Phone
    }
    return ""
}

func (m *CustomerRequest) GetAddresses() []*CustomerRequest_Address {
    if m != nil {
        return m.Addresses
    }
    return nil
}

type CustomerRequest_Address struct {
    Street            string `protobuf:"bytes,1,opt,name=street" json:"street,omitempty"`
    City              string `protobuf:"bytes,2,opt,name=city" json:"city,omitempty"`
    State             string `protobuf:"bytes,3,opt,name=state" json:"state,omitempty"`
    Zip               string `protobuf:"bytes,4,opt,name=zip" json:"zip,omitempty"`
    IsShippingAddress bool   `protobuf:"varint,5,opt,name=isShippingAddress" json:"isShippingAddress,omitempty"`
}

func (m *CustomerRequest_Address) Reset()                    { *m = CustomerRequest_Address{} }
func (m *CustomerRequest_Address) String() string            { return proto.CompactTextString(m) }
func (*CustomerRequest_Address) ProtoMessage()               {}
func (*CustomerRequest_Address) Descriptor() ([]byte, []int) { return fileDescriptor0, []int{0, 0} }

func (m *CustomerRequest_Address) GetStreet() string {
    if m != nil {
        return m.Street
    }
    return ""
}

func (m *CustomerRequest_Address) GetCity() string {
    if m != nil {
        return m.City
    }
    return ""
}

func (m *CustomerRequest_Address) GetState() string {
    if m != nil {
        return m.State
    }
    return ""
}

func (m *CustomerRequest_Address) GetZip() string {
    if m != nil {
        return m.Zip
    }
    return ""
}

func (m *CustomerRequest_Address) GetIsShippingAddress() bool {
    if m != nil {
        return m.IsShippingAddress
    }
    return false
}

type CustomerResponse struct {
    Id      int32 `protobuf:"varint,1,opt,name=id" json:"id,omitempty"`
    Success bool  `protobuf:"varint,2,opt,name=success" json:"success,omitempty"`
}

func (m *CustomerResponse) Reset()                    { *m = CustomerResponse{} }
func (m *CustomerResponse) String() string            { return proto.CompactTextString(m) }
func (*CustomerResponse) ProtoMessage()               {}
func (*CustomerResponse) Descriptor() ([]byte, []int) { return fileDescriptor0, []int{1} }

func (m *CustomerResponse) GetId() int32 {
    if m != nil {
        return m.Id
    }
    return 0
}

func (m *CustomerResponse) GetSuccess() bool {
    if m != nil {
        return m.Success
    }
    return false
}

type CustomerFilter struct {
    Keyword string `protobuf:"bytes,1,opt,name=keyword" json:"keyword,omitempty"`
}

func (m *CustomerFilter) Reset()                    { *m = CustomerFilter{} }
func (m *CustomerFilter) String() string            { return proto.CompactTextString(m) }
func (*CustomerFilter) ProtoMessage()               {}
func (*CustomerFilter) Descriptor() ([]byte, []int) { return fileDescriptor0, []int{2} }

func (m *CustomerFilter) GetKeyword() string {
    if m != nil {
        return m.Keyword
    }
    return ""
}

func init() {
    proto.RegisterType((*CustomerRequest)(nil), "customer.CustomerRequest")
    proto.RegisterType((*CustomerRequest_Address)(nil), "customer.CustomerRequest.Address")
    proto.RegisterType((*CustomerResponse)(nil), "customer.CustomerResponse")
    proto.RegisterType((*CustomerFilter)(nil), "customer.CustomerFilter")
}

// Reference imports to suppress errors if they are not otherwise used.
var _ context.Context
var _ grpc.ClientConn

// This is a compile-time assertion to ensure that this generated file
// is compatible with the grpc package it is being compiled against.
const _ = grpc.SupportPackageIsVersion4

// Client API for Customer service

type CustomerClient interface {
    // Get all Customers with filter - A server-to-client streaming RPC.
    GetCustomers(ctx context.Context, in *CustomerFilter, opts ...grpc.CallOption) (Customer_GetCustomersClient, error)
    // Create a new Customer - A simple RPC
    CreateCustomer(ctx context.Context, in *CustomerRequest, opts ...grpc.CallOption) (*CustomerResponse, error)
}

type customerClient struct {
    cc *grpc.ClientConn
}

func NewCustomerClient(cc *grpc.ClientConn) CustomerClient {
    return &customerClient{cc}
}

func (c *customerClient) GetCustomers(ctx context.Context, in *CustomerFilter, opts ...grpc.CallOption) (Customer_GetCustomersClient, error) {
    stream, err := grpc.NewClientStream(ctx, &_Customer_serviceDesc.Streams[0], c.cc, "/customer.Customer/GetCustomers", opts...)
    if err != nil {
        return nil, err
    }
    x := &customerGetCustomersClient{stream}
    if err := x.ClientStream.SendMsg(in); err != nil {
        return nil, err
    }
    if err := x.ClientStream.CloseSend(); err != nil {
        return nil, err
    }
    return x, nil
}

type Customer_GetCustomersClient interface {
    Recv() (*CustomerRequest, error)
    grpc.ClientStream
}

type customerGetCustomersClient struct {
    grpc.ClientStream
}

func (x *customerGetCustomersClient) Recv() (*CustomerRequest, error) {
    m := new(CustomerRequest)
    if err := x.ClientStream.RecvMsg(m); err != nil {
        return nil, err
    }
    return m, nil
}

func (c *customerClient) CreateCustomer(ctx context.Context, in *CustomerRequest, opts ...grpc.CallOption) (*CustomerResponse, error) {
    out := new(CustomerResponse)
    err := grpc.Invoke(ctx, "/customer.Customer/CreateCustomer", in, out, c.cc, opts...)
    if err != nil {
        return nil, err
    }
    return out, nil
}

// Server API for Customer service

type CustomerServer interface {
    // Get all Customers with filter - A server-to-client streaming RPC.
    GetCustomers(*CustomerFilter, Customer_GetCustomersServer) error
    // Create a new Customer - A simple RPC
    CreateCustomer(context.Context, *CustomerRequest) (*CustomerResponse, error)
}

func RegisterCustomerServer(s *grpc.Server, srv CustomerServer) {
    s.RegisterService(&_Customer_serviceDesc, srv)
}

func _Customer_GetCustomers_Handler(srv interface{}, stream grpc.ServerStream) error {
    m := new(CustomerFilter)
    if err := stream.RecvMsg(m); err != nil {
        return err
    }
    return srv.(CustomerServer).GetCustomers(m, &customerGetCustomersServer{stream})
}

type Customer_GetCustomersServer interface {
    Send(*CustomerRequest) error
    grpc.ServerStream
}

type customerGetCustomersServer struct {
    grpc.ServerStream
}

func (x *customerGetCustomersServer) Send(m *CustomerRequest) error {
    return x.ServerStream.SendMsg(m)
}

func _Customer_CreateCustomer_Handler(srv interface{}, ctx context.Context, dec func(interface{}) error, interceptor grpc.UnaryServerInterceptor) (interface{}, error) {
    in := new(CustomerRequest)
    if err := dec(in); err != nil {
        return nil, err
    }
    if interceptor == nil {
        return srv.(CustomerServer).CreateCustomer(ctx, in)
    }
    info := &grpc.UnaryServerInfo{
        Server:     srv,
        FullMethod: "/customer.Customer/CreateCustomer",
    }
    handler := func(ctx context.Context, req interface{}) (interface{}, error) {
        return srv.(CustomerServer).CreateCustomer(ctx, req.(*CustomerRequest))
    }
    return interceptor(ctx, in, info, handler)
}

var _Customer_serviceDesc = grpc.ServiceDesc{
    ServiceName: "customer.Customer",
    HandlerType: (*CustomerServer)(nil),
    Methods: []grpc.MethodDesc{
        {
            MethodName: "CreateCustomer",
            Handler:    _Customer_CreateCustomer_Handler,
        },
    },
    Streams: []grpc.StreamDesc{
        {
            StreamName:    "GetCustomers",
            Handler:       _Customer_GetCustomers_Handler,
            ServerStreams: true,
        },
    },
    Metadata: "customer.proto",
}

func init() { proto.RegisterFile("customer.proto", fileDescriptor0) }

var fileDescriptor0 = []byte{
    // 326 bytes of a gzipped FileDescriptorProto
    0x1f, 0x8b, 0x08, 0x00, 0x00, 0x00, 0x00, 0x00, 0x02, 0xff, 0x74, 0x92, 0xef, 0x4a, 0xc3, 0x30,
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    0x78, 0xb2, 0x10, 0x2c, 0x62, 0x89, 0x9f, 0x7a, 0xb2, 0xe0, 0x1c, 0x7a, 0x65, 0xb6, 0x42, 0xe1,
    0x45, 0x2c, 0x19, 0xa5, 0x36, 0xe6, 0x67, 0xe0, 0xe3, 0x2a, 0x93, 0x4b, 0xd1, 0xb5, 0xc9, 0x06,
    0x4c, 0xb6, 0x5e, 0x54, 0x25, 0x8a, 0x5e, 0x93, 0xb5, 0xc0, 0xef, 0x61, 0x94, 0x15, 0x85, 0x42,
    0x22, 0x24, 0xe1, 0x47, 0xdd, 0xe4, 0x68, 0x7a, 0x39, 0xd9, 0x1a, 0xfd, 0xb9, 0x7d, 0xf2, 0xd0,
    0x94, 0xa6, 0xbb, 0x9e, 0xf0, 0x8b, 0xc1, 0xa0, 0x4d, 0xf3, 0x73, 0xe8, 0x93, 0x56, 0x88, 0xda,
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    0x79, 0x21, 0xeb, 0x5a, 0x96, 0xaf, 0xed, 0x45, 0xc2, 0x8f, 0x58, 0x32, 0x4c, 0xf7, 0x0f, 0xe2,
    0x3b, 0x18, 0xef, 0x9c, 0xa9, 0xae, 0x4a, 0xc2, 0xbd, 0x95, 0x09, 0x18, 0xd0, 0x3a, 0xcf, 0xcd,
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    0xd3, 0x62, 0x60, 0x02, 0x00, 0x00,
}

server/main.go

package main

import (
    "log"
    "net"
    "strings"

    "golang.org/x/net/context"
    "google.golang.org/grpc"

    pb "go_grpc_protobuf/customer"
)

const (
    port = ":50051"
)

// server is used to implement customer.CustomerServer.
type server struct {
    savedCustomers []*pb.CustomerRequest
}

// CreateCustomer creates a new Customer
func (s *server) CreateCustomer(ctx context.Context, in *pb.CustomerRequest) (*pb.CustomerResponse, error) {
    s.savedCustomers = append(s.savedCustomers, in)
    return &pb.CustomerResponse{Id: in.Id, Success: true}, nil
}

// GetCustomers returns all customers by given filter
func (s *server) GetCustomers(filter *pb.CustomerFilter, stream pb.Customer_GetCustomersServer) error {
    for _, customer := range s.savedCustomers {
        if filter.Keyword != "" {
            if !strings.Contains(customer.Name, filter.Keyword) {
                continue
            }
        }
        if err := stream.Send(customer); err != nil {
            return err
        }
    }
    return nil
}

func main() {
    lis, err := net.Listen("tcp", port)
    if err != nil {
        log.Fatalf("failed to listen: %v", err)
    }
    // Creates a new gRPC server
    s := grpc.NewServer()
    pb.RegisterCustomerServer(s, &server{})
    s.Serve(lis)
}

client/main.go

package main

import (
    "io"
    "log"

    "golang.org/x/net/context"
    "google.golang.org/grpc"

    pb "go_grpc_protobuf/customer"
)

const (
    address = "localhost:50051"
)

// createCustomer calls the RPC method CreateCustomer of CustomerServer
func createCustomer(client pb.CustomerClient, customer *pb.CustomerRequest) {
    resp, err := client.CreateCustomer(context.Background(), customer)
    if err != nil {
        log.Fatalf("Could not create Customer: %v", err)
    }
    if resp.Success {
        log.Printf("A new Customer has been added with id: %d", resp.Id)
    }
}

// getCustomers calls the RPC method GetCustomers of CustomerServer
func getCustomers(client pb.CustomerClient, filter *pb.CustomerFilter) {
    // calling the streaming API
    stream, err := client.GetCustomers(context.Background(), filter)
    if err != nil {
        log.Fatalf("Error on get customers: %v", err)
    }
    for {
        customer, err := stream.Recv()
        if err == io.EOF {
            break
        }
        if err != nil {
            log.Fatalf("%v.GetCustomers(_) = _, %v", client, err)
        }
        log.Printf("Customer: %v", customer)
    }
}
func main() {
    // Set up a connection to the gRPC server.
    conn, err := grpc.Dial(address, grpc.WithInsecure())
    if err != nil {
        log.Fatalf("did not connect: %v", err)
    }
    defer conn.Close()
    // Creates a new CustomerClient
    client := pb.NewCustomerClient(conn)

    customer := &pb.CustomerRequest{
        Id:    101,
        Name:  "Shiju Varghese",
        Email: "shiju@xyz.com",
        Phone: "732-757-2923",
        Addresses: []*pb.CustomerRequest_Address{
            &pb.CustomerRequest_Address{
                Street:            "1 Mission Street",
                City:              "San Francisco",
                State:             "CA",
                Zip:               "94105",
                IsShippingAddress: false,
            },
            &pb.CustomerRequest_Address{
                Street:            "Greenfield",
                City:              "Kochi",
                State:             "KL",
                Zip:               "68356",
                IsShippingAddress: true,
            },
        },
    }

    // Create a new customer
    createCustomer(client, customer)

    customer = &pb.CustomerRequest{
        Id:    102,
        Name:  "Irene Rose",
        Email: "irene@xyz.com",
        Phone: "732-757-2924",
        Addresses: []*pb.CustomerRequest_Address{
            &pb.CustomerRequest_Address{
                Street:            "1 Mission Street",
                City:              "San Francisco",
                State:             "CA",
                Zip:               "94105",
                IsShippingAddress: true,
            },
        },
    }

    // Create a new customer
    createCustomer(client, customer)
    // Filter with an empty Keyword
    filter := &pb.CustomerFilter{Keyword: ""}
    getCustomers(client, filter)
}

运行server，运行client，输出：

2017/12/07 11:55:59 A new Customer has been added with id: 101
2017/12/07 11:55:59 A new Customer has been added with id: 102
2017/12/07 11:55:59 Customer: id:101 name:"Shiju Varghese" email:"shiju@xyz.com" phone:"732-757-2923" addresses:"1 Mission Street" city:"San Francisco" state:"CA" zip:"94105" > addresses:"Greenfield" city:"Kochi" state:"KL" zip:"68356" isShippingAddress:true >
2017/12/07 11:55:59 Customer: id:102 name:"Irene Rose" email:"irene@xyz.com" phone:"732-757-2924" addresses:"1 Mission Street" city:"San Francisco" state:"CA" zip:"94105" isShippingAddress:true >