gRPC 是一个高性能、开源和通用的 RPC 框架，面向移动和 HTTP/2 设计，带来诸如双向流、流控、头部压缩、单 TCP 连接上的多复用请求等特。这些特性使得其在移动设备上表现更好，更省电和节省空间占用。
安装 protobuf
grpc使用protobuf作为IDL(interface descriton language)，且要求protobuf 3.0以上，这里我们直接选用当前最新版本 3.8，git下载地址。
选择操作系统对应的版本下载，这里我们直接使用已经编译好的protoc可执行文件（或者下载安装包编译安装）。
wget https://github.com/protocolbuffers/protobuf/releases/download/v3.8.0-rc1/protoc-3.8.0-rc-1-linux-x86_64.zip
tar -zxvf protoc-3.8.0-rc-1-linux-x86_64.zip
mv protoc-3.8.0-rc-1-linux-x86_64 /usr/local/protoc
ln -s /usr/local/protoc/bin/protoc /usr/local/bin/protoc
#查看 protoc
protoc --version安装 protoc-gen-go
protoc-gen-go是Go Grpc的protoc编译插件，protobuf内置了许多高级语言的编译器，但没有Go的。
# 运行 protoc -h 命令可以发现内置的只支持以下语言
protoc -h
...
--cpp_out=OUT_DIR Generate C++ header and source.
--csharp_out=OUT_DIR Generate C# source file.
--java_out=OUT_DIR Generate Java source file.
--js_out=OUT_DIR Generate JavaScript source.
--objc_out=OUT_DIR Generate Objective C header and source.
--php_out=OUT_DIR Generate PHP source file.
--python_out=OUT_DIR Generate Python source file.
--ruby_out=OUT_DIR Generate Ruby source file.
...所以我们使用protoc编译生成Go版的grpc时，需要先安装此插件。
go get -u github.com/golang/protobuf/{protoc-gen-go}安装 grpc-go
grpc-go包含了Go的grpc库。
go get google.golang.org/grpc 可能会被墙掉了，使用如下方式手动安装。
git clone https://github.com/grpc/grpc-go.git $GOPATH/src/google.golang.org/grpc
git clone https://github.com/golang/net.git $GOPATH/src/golang.org/x/net
git clone https://github.com/golang/text.git $GOPATH/src/golang.org/x/text
git clone https://github.com/google/go-genproto.git $GOPATH/src/google.golang.org/genproto
cd $GOPATH/src/
go install google.golang.org/grpcGrpc的四种模式
grpc借口的类型分为一下四种: A为接受参数,B为返回参数
- rpc GetFeature(Point) returns (Feature) {} 普通调用:A-B
- rpc ListFeatures(Rectangle) returns (stream Feature) {} 单向流:A - B(流)
- rpc RecordRoute(stream Point) returns (RouteSummary) {} 单向流:A(流) - B
- rpc RouteChat(stream RouteNote) returns (stream RouteNote) {} 双向流:A(流) - B(流)
我们只演示最基础的普通调用，开始撸。
Go实例
下面我们将创建一个提供CURD操作的User服务。
#创建一个 grpc 服务库
mkdir $GOPATH/src/grpc/user -p && cd $GOPATH/src/grpc定义服务接口
使用proto3 IDL编写如下的用户服务。vi user.proto
syntax = "proto3";
// user 包
package user;
// User 服务及服务接口的定义
service User {
rpc UserIndex(UserIndexRequest) returns (UserIndexResponse) {}
rpc UserView(UserViewRequest) returns (UserViewResponse) {}
rpc UserPost(UserPostRequest) returns (UserPostResponse) {}
rpc UserDelete(UserDeleteRequest) returns (UserDeleteResponse) {}
}
// 用户实体模型
message UserEntity {
string name = 1;
int32 age = 2;
}
// User 服务的各个接口的请求/响应结构
message UserIndexRequest {
int32 page = 1;
int32 page_size = 2;
}
message UserIndexResponse {
int32 err = 1;
string msg = 2;
// 返回一个 UserEntity 对象的列表数据
repeated UserEntity data = 3;
}
message UserViewRequest {
int32 uid = 1;
}
message UserViewResponse {
int32 err = 1;
string msg = 2;
// 返回一个 UserEntity 对象
UserEntity data = 3;
}
message UserPostRequest {
string name = 1;
string password = 2;
int32 age = 3;
}
message UserPostResponse {
int32 err = 1;
string msg = 2;
}
message UserDeleteRequest {
int32 uid = 1;
}
message UserDeleteResponse {
int32 err = 1;
string msg = 2;
}生成接口库
# 将 User 服务的所属包 user package 存放在 $GOPATH/src/grpc/user 下
protoc -I. --go_out=plugins=grpc:./user user.proto编写服务端
vi server.go
package main
import (
"context"
"log"
"net"
"google.golang.org/grpc"
"google.golang.org/grpc/reflection"
user "grpc/user"
)
const (
port = ":50051"
)
type UserService struct {
// 实现 User 服务的业务对象
}
// UserService 实现了 User 服务接口中声明的所有方法
func (userService *UserService) UserIndex(ctx context.Context, in *user.UserIndexRequest) (*user.UserIndexResponse, error) {
log.Printf("receive user index request: page %d page_size %d", in.Page, in.PageSize)
return &user.UserIndexResponse{
Err: 0,
Msg: "success",
Data: []*user.UserEntity{
{Name: "big_cat", Age: 28},
{Name: "sqrt_cat", Age: 29},
},
}, nil
}
func (userService *UserService) UserView(ctx context.Context, in *user.UserViewRequest) (*user.UserViewResponse, error) {
log.Printf("receive user view request: uid %d", in.Uid)
return &user.UserViewResponse{
Err: 0,
Msg: "success",
Data: &user.UserEntity{Name: "james", Age: 28},
}, nil
}
func (userService *UserService) UserPost(ctx context.Context, in *user.UserPostRequest) (*user.UserPostResponse, error) {
log.Printf("receive user post request: name %s password %s age %d", in.Name, in.Password, in.Age)
return &user.UserPostResponse{
Err: 0,
Msg: "success",
}, nil
}
func (userService *UserService) UserDelete(ctx context.Context, in *user.UserDeleteRequest) (*user.UserDeleteResponse, error) {
log.Printf("receive user delete request: uid %d", in.Uid)
return &user.UserDeleteResponse{
Err: 0,
Msg: "success",
}, nil
}
func main() {
lis, err := net.Listen("tcp", port)
if err != nil {
log.Fatalf("failed to listen: %v", err)
}
// 创建 RPC 服务容器
grpcServer := grpc.NewServer()
// 为 User 服务注册业务实现 将 User 服务绑定到 RPC 服务容器上
user.RegisterUserServer(grpcServer, &UserService{})
// 注册反射服务 这个服务是CLI使用的 跟服务本身没有关系
reflection.Register(grpcServer)
if err := grpcServer.Serve(lis); err != nil {
log.Fatalf("failed to serve: %v", err)
}
}编写客户端
vi client.go
package main
import (
"context"
"fmt"
"log"
"time"
"google.golang.org/grpc"
user "grpc/user"
)
const (
address = "localhost:50051"
)
func main() {
//建立链接
conn, err := grpc.Dial(address, grpc.WithInsecure())
if err != nil {
log.Fatalf("did not connect: %v", err)
}
defer conn.Close()
userClient := user.NewUserClient(conn)
// 设定请求超时时间 3s
ctx, cancel := context.WithTimeout(context.Background(), time.Second*3)
defer cancel()
// UserIndex 请求
userIndexReponse, err := userClient.UserIndex(ctx, &user.UserIndexRequest{Page: 1, PageSize: 12})
if err != nil {
log.Printf("user index could not greet: %v", err)
}
if 0 == userIndexReponse.Err {
log.Printf("user index success: %s", userIndexReponse.Msg)
// 包含 UserEntity 的数组列表
userEntityList := userIndexReponse.Data
for _, row := range userEntityList {
fmt.Println(row.Name, row.Age)
}
} else {
log.Printf("user index error: %d", userIndexReponse.Err)
}
// UserView 请求
userViewResponse, err := userClient.UserView(ctx, &user.UserViewRequest{Uid: 1})
if err != nil {
log.Printf("user view could not greet: %v", err)
}
if 0 == userViewResponse.Err {
log.Printf("user view success: %s", userViewResponse.Msg)
userEntity := userViewResponse.Data
fmt.Println(userEntity.Name, userEntity.Age)
} else {
log.Printf("user view error: %d", userViewResponse.Err)
}
// UserPost 请求
userPostReponse, err := userClient.UserPost(ctx, &user.UserPostRequest{Name: "big_cat", Password: "123456", Age: 29})
if err != nil {
log.Printf("user post could not greet: %v", err)
}
if 0 == userPostReponse.Err {
log.Printf("user post success: %s", userPostReponse.Msg)
} else {
log.Printf("user post error: %d", userPostReponse.Err)
}
// UserDelete 请求
userDeleteReponse, err := userClient.UserDelete(ctx, &user.UserDeleteRequest{Uid: 1})
if err != nil {
log.Printf("user delete could not greet: %v", err)
}
if 0 == userDeleteReponse.Err {
log.Printf("user delete success: %s", userDeleteReponse.Msg)
} else {
log.Printf("user delete error: %d", userDeleteReponse.Err)
}
}启动服务/请求服务
go run server.go
# 新建一个窗口
go run client.go运行结果
#server
[root@localhost rpc]# go run server.go
2019/05/16 00:28:01 receive user index request: page 1 page_size 12
2019/05/16 00:28:01 receive user view request: uid 1
2019/05/16 00:28:01 receive user post request: name big_cat password 123456 age 29
2019/05/16 00:28:01 receive user delete request: uid 1
#client
[root@localhost rpc]# go run client.go
2019/05/16 00:28:01 user index success: success
big_cat 28
sqrt_cat 29
2019/05/16 00:28:01 user view success: success
james 28
2019/05/16 00:28:01 user post success: success
2019/05/16 00:28:01 user delete success: successgrpc面向服务接口编程大致就是这样啦，你可以更好的组织业务库，我这里全放在package main里了，后面的工作就是把数据库拉进来了。
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