Golang Grpc 例子
GitHub源码地址
如何运行 helloworld 例子
helloworld
1、$ git clone git@github.com:yoloyi/go-exercise-example.git
2、$ cd /go-exercise-example/grpc
3、$ go install
4、$ go run helloworld/cmd/service/main.go
5、$ go run helloworld/cmd/client/main.go world
例子学习
protoc 是 Protocol Buffers 的一个工具，负责生成协议的序列化、反序列化相应语言的代码
1、下载 protoc
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| https://github.com/protocolbuffers/protobuf/releases
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选择对应的本机的环境，下载相应的 protoc
2、把bin/protoc 移动到 PATH 目录下
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| mv bin/protoc /usr/local/bin
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3、检查 protoc 是否正确移动
Golang
1、安装 grpc
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| go get -u google.golang.org/grpc
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2、安装 protoc 插件 protoc-gen-go
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| go get -u github.com/golang/protobuf/protoc-gen-go
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3、检查 GOBIN 是否设置，以及 GOBIN 是否加入到 PATH 里面
如何使用 protoc
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| Usage: protoc [OPTION] PROTO_FILES
Parse PROTO_FILES and generate output based on the options given:
-IPATH, --proto_path=PATH Specify the directory in which to search for
imports. May be specified multiple times;
directories will be searched in order. If not
given, the current working directory is used.
If not found in any of the these directories,
the --descriptor_set_in descriptors will be
checked for required proto file.
--version Show version info and exit.
-h, --help Show this text and exit.
--encode=MESSAGE_TYPE Read a text-format message of the given type
from standard input and write it in binary
to standard output. The message type must
be defined in PROTO_FILES or their imports.
--decode=MESSAGE_TYPE Read a binary message of the given type from
standard input and write it in text format
to standard output. The message type must
be defined in PROTO_FILES or their imports.
--decode_raw Read an arbitrary protocol message from
standard input and write the raw tag/value
pairs in text format to standard output. No
PROTO_FILES should be given when using this
flag.
--descriptor_set_in=FILES Specifies a delimited list of FILES
each containing a FileDescriptorSet (a
protocol buffer defined in descriptor.proto).
The FileDescriptor for each of the PROTO_FILES
provided will be loaded from these
FileDescriptorSets. If a FileDescriptor
appears multiple times, the first occurrence
will be used.
-oFILE, Writes a FileDescriptorSet (a protocol buffer,
--descriptor_set_out=FILE defined in descriptor.proto) containing all of
the input files to FILE.
--include_imports When using --descriptor_set_out, also include
all dependencies of the input files in the
set, so that the set is self-contained.
--include_source_info When using --descriptor_set_out, do not strip
SourceCodeInfo from the FileDescriptorProto.
This results in vastly larger descriptors that
include information about the original
location of each decl in the source file as
well as surrounding comments.
--dependency_out=FILE Write a dependency output file in the format
expected by make. This writes the transitive
set of input file paths to FILE
--error_format=FORMAT Set the format in which to print errors.
FORMAT may be 'gcc' (the default) or 'msvs'
(Microsoft Visual Studio format).
--print_free_field_numbers Print the free field numbers of the messages
defined in the given proto files. Groups share
the same field number space with the parent
message. Extension ranges are counted as
occupied fields numbers.
--plugin=EXECUTABLE Specifies a plugin executable to use.
Normally, protoc searches the PATH for
plugins, but you may specify additional
executables not in the path using this flag.
Additionally, EXECUTABLE may be of the form
NAME=PATH, in which case the given plugin name
is mapped to the given executable even if
the executable's own name differs.
--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.
@<filename> Read options and filenames from file. If a
relative file path is specified, the file
will be searched in the working directory.
The --proto_path option will not affect how
this argument file is searched. Content of
the file will be expanded in the position of
@<filename> as in the argument list. Note
that shell expansion is not applied to the
content of the file (i.e., you cannot use
quotes, wildcards, escapes, commands, etc.).
Each line corresponds to a single argument,
even if it contains spaces.
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| protoc --go_out=. {PROTO_DIR}
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使用例子
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| protoc -I proto --go_out=plugins=grpc:./helloworld/proto helloworld.proto
// -I 类似于 WORK_DIR，工作目录，proto 文件 去哪个文件里面找
// --go_out 这个是 protoc-gen-go 的扩展，原本 protoc 里面是没有 go 的代码生成，我们需要安装这个插件
// 后面接文件名字
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HelloWorld Grpc
1、新建 helloworld.proto
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| // proto 版本，有 2，3两个版本。必须写
syntax = "proto3";
package helloworld;
// 注册 grpc 的方法
service Greeter {
rpc SayHello (HelloRequest) returns (HelloReply);
}
// 请求参数
message HelloRequest {
string name = 1;
}
// 返回参数
message HelloReply {
string message = 1;
}
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2、使用命令 protoc -I helloworld/proto --go_out=plugins=grpc:./helloworld/proto helloworld.proto 自动生成 .pb.go 代码
3、编写 Service 端
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package main
import (
"context"
"fmt"
"google.golang.org/grpc"
"log"
"net"
pb "grpc/helloworld/proto"
)
const port = ":50051"
// 组合一个 server
type service struct {
pb.UnimplementedGreeterServer
}
// grpc 重写的方法
// 如果不重写，会出现 error
func (s *service) SayHello(ctx context.Context, in *pb.HelloRequest) (*pb.HelloReply, error) {
str := fmt.Sprintf("Hello %s", in.GetName())
log.Println(str)
return &pb.HelloReply{Message: str}, nil
}
func main() {
fmt.Println("-------------------")
lis, err := net.Listen("tcp", port)
if err != nil {
log.Fatalln(err)
}
s := grpc.NewServer()
// 注册一个 grpc
pb.RegisterGreeterServer(s, &service{})
fmt.Println("Hello world GRpc start")
// 等待阻塞
if err := s.Serve(lis); err != nil {
log.Fatalf("failed to serve：%v", err)
}
}
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3、编写 Client 端
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package main
import (
"fmt"
"golang.org/x/net/context"
"google.golang.org/grpc"
"log"
"os"
pb "grpc/helloworld/proto"
"time"
)
const (
address string = "localhost:50051"
defaultName string = "world"
)
func main() {
conn, err := grpc.Dial(address, grpc.WithInsecure()) // 判断 grpc service 是否活着
// grpc.WithInsecure() 禁用传递安全型，
if err != nil {
log.Fatalln(err)
}
defer conn.Close()
c := pb.NewGreeterClient(conn) // 创建一个 client，这里的client 是 protoc 生成的
name := defaultName
if len(os.Args) > 1 {
name = os.Args[1]
}
ctx, cancel := context.WithTimeout(context.Background(), time.Second)
defer cancel()
r, err := c.SayHello(ctx, &pb.HelloRequest{
Name: name,
}) // 调用Service 的 say hello 方法
if err != nil {
log.Fatalln(err)
}
fmt.Println("Get Rpc request message", r.GetMessage())
}
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4、运行
首先我们要运行 service 使得 service 常驻。然后运行我们的 client 客户端就可以看到相应的返回结果。
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$ go run helloworld/cmd/service/main.go
//out: -------------------
// Hello world GRpc start
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起一个新的窗口
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| $ go run helloworld/cmd/client/main.go world
//out: Get Rpc request message Hello world
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