gRPCを試してみる

前提条件

端末: Apple Mac mini
チップ : Apple M2 Pro
OS : macOS Ventura 13.2.1
インストーラー : Homebrew
インストール済コマンド : tree
プログラミング言語 : Go言語

参考資料

gRPC Quick start

インストール

protocコマンドを使うためにprotobufのインストール
- sharl@macMini ~ %

brew install protobuf

実行結果

==> Fetching dependencies for protobuf: abseil
==> Fetching abseil
==> Downloading https://ghcr.io/v2/homebrew/core/abseil/manifests/20230125.3-1
######################################################################################################################## 100.0%
==> Downloading https://ghcr.io/v2/homebrew/core/abseil/blobs/sha256:c789ff211d0d81fba211ffa4abc0a0e5ce430698ae0e590057cbeeb73d
######################################################################################################################## 100.0%
==> Fetching protobuf
==> Downloading https://ghcr.io/v2/homebrew/core/protobuf/manifests/23.4
######################################################################################################################## 100.0%
==> Downloading https://ghcr.io/v2/homebrew/core/protobuf/blobs/sha256:eb86d06abace7c985b21ccac17ea418131e17689c9fdeddbcaa998d7
######################################################################################################################## 100.0%
==> Installing dependencies for protobuf: abseil
==> Installing protobuf dependency: abseil
==> Pouring abseil--20230125.3.arm64_ventura.bottle.1.tar.gz
🍺  /opt/homebrew/Cellar/abseil/20230125.3: 723 files, 10.6MB
==> Installing protobuf
==> Pouring protobuf--23.4.arm64_ventura.bottle.tar.gz
==> Caveats
Emacs Lisp files have been installed to:
  /opt/homebrew/share/emacs/site-lisp/protobuf
==> Summary
🍺  /opt/homebrew/Cellar/protobuf/23.4: 389 files, 12.2MB
==> Running `brew cleanup protobuf`...
Disable this behaviour by setting HOMEBREW_NO_INSTALL_CLEANUP.
Hide these hints with HOMEBREW_NO_ENV_HINTS (see `man brew`).
==> Caveats
==> protobuf
Emacs Lisp files have been installed to:
  /opt/homebrew/share/emacs/site-lisp/protobuf

sharl@macMini ~ %

protoc --version

実行結果

```bash
libprotoc 23.4

sharl@macMini ~ %

mkdir -p ./dev/grpc/test ; cd ./dev/grpc/test

sharl@macMini test %

go install google.golang.org/protobuf/cmd/protoc-gen-go@latest
go install google.golang.org/grpc/cmd/protoc-gen-go-grpc@latest

実行結果

go: downloading google.golang.org/protobuf v1.31.0
go: downloading google.golang.org/grpc v1.57.0
go: downloading google.golang.org/grpc/cmd/protoc-gen-go-grpc v1.3.0
go: downloading google.golang.org/protobuf v1.28.1

sharl@macMini test %

export PATH="$PATH:$(go env GOPATH)/bin"

sharl@macMini ~ %

protoc-gen-go --version ; protoc-gen-go-grpc --version

実行結果

protoc-gen-go v1.31.0
protoc-gen-go-grpc 1.3.0

Teru room

サンプルコードのインストール

sharl@macMini test %

git clone -b v1.57.0 --depth 1 https://github.com/grpc/grpc-go

実行結果

Cloning into 'grpc-go'...
remote: Enumerating objects: 1349, done.
remote: Counting objects: 100% (1349/1349), done.
remote: Compressing objects: 100% (1144/1144), done.
remote: Total 1349 (delta 212), reused 543 (delta 68), pack-reused 0
Receiving objects: 100% (1349/1349), 2.14 MiB | 11.10 MiB/s, done.
Resolving deltas: 100% (212/212), done.
Note: switching to '87bf02ad24f6cc071d2553eb5d62332194bba1fe'.

You are in 'detached HEAD' state. You can look around, make experimental
changes and commit them, and you can discard any commits you make in this
state without impacting any branches by switching back to a branch.

If you want to create a new branch to retain commits you create, you may
do so (now or later) by using -c with the switch command. Example:

  git switch -c <new-branch-name>

Or undo this operation with:

  git switch -

Turn off this advice by setting config variable advice.detachedHead to false

sharl@macMini test %

cd grpc-go/examples/helloworld ; tree

実行結果

sharl@macMini helloworld % tree
.
├── README.md
├── greeter_client
│   └── main.go
├── greeter_server
│   └── main.go
└── helloworld
    ├── helloworld.pb.go
    ├── helloworld.proto
    └── helloworld_grpc.pb.go

4 directories, 6 files

サンプルコード

greeter_server/main.go

// Package main implements a server for Greeter service.
package main

import (
        "context"
        "flag"
        "fmt"
        "log"
        "net"

        "google.golang.org/grpc"
        pb "google.golang.org/grpc/examples/helloworld/helloworld"
)

var (
        port = flag.Int("port", 50051, "The server port")
)

// server is used to implement helloworld.GreeterServer.
type server struct {
        pb.UnimplementedGreeterServer
}

// SayHello implements helloworld.GreeterServer
func (s *server) SayHello(ctx context.Context, in *pb.HelloRequest) (*pb.HelloReply, error) {
        log.Printf("Received: %v", in.GetName())
        return &pb.HelloReply{Message: "Hello " + in.GetName()}, nil
}

greeter_client/main.go

// Package main implements a server for Greeter service.
// Package main implements a client for Greeter service.
package main

import (
        "context"
        "flag"
        "log"
        "time"

        "google.golang.org/grpc"
        "google.golang.org/grpc/credentials/insecure"
        pb "google.golang.org/grpc/examples/helloworld/helloworld"
)

const (
        defaultName = "world"
)

var (
        addr = flag.String("addr", "localhost:50051", "the address to connect to")
        name = flag.String("name", defaultName, "Name to greet")
)

func main() {
        flag.Parse()
        // Set up a connection to the server.
        conn, err := grpc.Dial(*addr, grpc.WithTransportCredentials(insecure.NewCredentials()))
        if err != nil {
                log.Fatalf("did not connect: %v", err)

Teru room

サンプルコードの実行

別ターミナル起動
- sharl@macMini ~ %

cd ./dev/grpc/test/grpc-go/examples/helloworld ; go run greeter_server/main.go

実行結果

go: downloading google.golang.org/genproto/googleapis/rpc v0.0.0-20230525234030-28d5490b6b19
go: downloading google.golang.org/protobuf v1.30.0
go: downloading golang.org/x/net v0.9.0
go: downloading github.com/golang/protobuf v1.5.3
go: downloading google.golang.org/genproto v0.0.0-20230526161137-0005af68ea54
go: downloading golang.org/x/text v0.9.0
2023/08/20 17:24:32 server listening at [::]:50051

別ターミナル起動
- sharl@macMini ~ %

cd ./dev/grpc/test/grpc-go/examples/helloworld ; go run greeter_client/main.go

実行結果

2023/08/20 17:29:05 Greeting: Hello world

Teru room

gRPCサービスのアップデート

Protocol buffersのアップデート

アップデート前

helloworld/helloworld.proto

syntax = "proto3";

option go_package = "google.golang.org/grpc/examples/helloworld/helloworld";
option java_multiple_files = true;
option java_package = "io.grpc.examples.helloworld";
option java_outer_classname = "HelloWorldProto";

package helloworld;

// The greeting service definition.
service Greeter {
  // Sends a greeting
  rpc SayHello (HelloRequest) returns (HelloReply) {}
}

// The request message containing the user's name.
message HelloRequest {
  string name = 1;
}

// The response message containing the greetings
message HelloReply {
  string message = 1;
}

アップデート後
- GreeterサービスにSayHelloAgain()メソッドを追加

helloworld/helloworld.proto

........
// The greeting service definition.
service Greeter {
  // Sends a greeting
  rpc SayHello (HelloRequest) returns (HelloReply) {}
  // Sends another greeting
  rpc SayHelloAgain (HelloRequest) returns (HelloReply) {}
}
........

Teru room

gRPCコードの再生成

sharl@macMini ~ %

cd dev/grpc/test/grpc-go/examples/helloworld 
protoc --go_out=. --go_opt=paths=source_relative \
    --go-grpc_out=. --go-grpc_opt=paths=source_relative \
    helloworld/helloworld.proto

helloworld.pb.goとhelloworld_grpc.pb.goが更新されていることを確認
- sharl@macMini helloworld %

ls -l helloworld

実行結果

total 48
-rw-r--r--  1 sharl  staff  8757  8 20 22:40 helloworld.pb.go
-rw-r--r--  1 sharl  staff  1257  8 20 17:55 helloworld.proto
-rw-r--r--  1 sharl  staff  5730  8 20 22:40 helloworld_grpc.pb.go

Teru room

サーバーの更新

greeter_server/main.goにSayHelloAgain関数の追加

greeter_server/main.go

func (s *server) SayHelloAgain(ctx context.Context, in *pb.HelloRequest) (*pb.HelloReply, error) {
        return &pb.HelloReply{Message: "Hello again " + in.GetName()}, nil
}

クライアントの更新

greeter_client/main.goのmain関数にSayHelloAgain関数の呼び出しを追加

greeter_server/main.go

r, err = c.SayHelloAgain(ctx, &pb.HelloRequest{Name: *name})
if err != nil {
        log.Fatalf("could not greet: %v", err)
}
log.Printf("Greeting: %s", r.GetMessage())

Teru room

サービスの実行

別ターミナルでサーバーを実行
- sharl@macMini helloworld %

cd ./helloworld ; go run greeter_server/main.go

実行結果

stat greeter_server/main.go: no such file or directory
sharl@macMini helloworld % pwd
/Users/sharl/dev/grpc/test/grpc-go/examples/helloworld/helloworld
sharl@macMini helloworld % cd .. 
sharl@macMini helloworld % pwd
/Users/sharl/dev/grpc/test/grpc-go/examples/helloworld
sharl@macMini helloworld % cd /Users/sharl/dev/grpc/test/grpc-go/examples/helloworld ; go run greeter_server/main.go 
2023/08/20 23:20:56 server listening at [::]:50051

別ターミナルでクライアントを実行
- sharl@macMini helloworld %

cd /Users/sharl/dev/grpc/test/grpc-go/examples/helloworld ; go run greeter_client/main.go --name=高橋

実行結果

2023/08/20 23:24:49 Greeting: Hello 高橋
2023/08/20 23:24:49 Greeting: Hello again 高橋

Teru room

sharl@macMini grpc % go mod init addressbook

実行結果

go: creating new go.mod: module addressbook
go: to add module requirements and sums:
	go mod tidy