grpc-sample

this repo is sample to help you understand gRPC.

System

Directory

.
├── README.md
├── go.mod
├── go.sum
├── pinger
│   ├── client
│   │   └── client.go
│   ├── lib // protocによって生成されるGoコード
│   │   ├── pinger.pb.go
│   │   └── pinger_grpc.pb.go
│   └── server.go // gRPCサーバー
├── proto
│   └── pinger.proto // IDL
└── server // gRPCスタブ
    ├── Gemfile
    ├── Gemfile.lock
    ├── README.md
    ├── Rakefile
    ├── app
    ├── bin
    ├── config
    ├── config.ru
    ├── lib // protocによって生成されるRubyコード
    │   ├── pinger_pb.rb
    │   └── pinger_services_pb.rb
    ├── log
    ├── public
    ├── test
    ├── tmp
    └── vendor

Install

• Ruby
• Go
• protobuf

grpc-sample $ ruby --version
ruby 2.6.6p146 (2020-03-31 revision 67876) [x86_64-darwin19]

grpc-sample $ go version
go version go1.17 darwin/amd64

grpc-sample $ brew install protobuf
grpc-sample $ protoc --version
libprotoc 3.17.3

VSCode Extention

If you want syntax highlighting or code-formatter

• vscode-proto3
• Clang-Format

grpc-sample $ brew install clang-format

Definition .proto

Create a gRPC server in Go

FYI: https://developers.google.com/protocol-buffers/docs/reference/go-generated#package

For Go 1.16 or later, you need to install the Go code generation plugin with the following command

grpc-sample　$ go install google.golang.org/protobuf/cmd/protoc-gen-go@v1.26
grpc-sample　$ go install google.golang.org/grpc/cmd/protoc-gen-go-grpc@v1.1

Also, add the following options to pinger.proto.

option go_package = "./lib";

Auto Go code generation

grpc-sample　$ protoc -I ./proto pinger.proto --go_out=./pinger --go-grpc_out=./pinger
grpc-sample　$ tree pinger
pinger
├── lib
│   ├── pinger.pb.go
│   └── pinger_grpc.pb.go
└── server.go

Start gRPC server in Go

pinger $ go run server.go
2021/10/03 15:42:53 Pinger listening at [::]:5300

Create a client to check if the gRPC server is running

Keep it running gRPC server

pinger $ go run server.go
2021/10/03 15:42:53 Pinger listening at [::]:5300

Access to client

client $ go run client.go
Pong: text:"pong"

Create Stub in Rails

Install Rails

Create in Rails 5 api mode

server $ bundle init
server $ echo 'gem "rails", ">=5.2.2.1"' >> Gemfile
server $ bundle exec rails new . --api -O
server $ bin/rails server

Auto Ruby code generation

server $ echo "gem 'grpc'" >> Gemfile
server $ echo "gem 'grpc-tools'" >> Gemfile
server $ bundle install

server $ bundle exec grpc_tools_ruby_protoc -I ../proto --ruby_out=lib --grpc_out=lib ../proto/pinger.proto

server $ tree lib
lib
├── pinger_pb.rb
├── pinger_services_pb.rb
└── tasks

Invoke from Application Controller

def ping
    pinger_stub = Pinger::Pinger::Stub.new('localhost:5300', :this_channel_is_insecure)

    pong = pinger_stub.ping(Pinger::Empty.new)
    render json: { pong: pong.text }
end

Start Rails server and Access to URL

Start gRPC server in Go

pinger $ go run server.go
2021/10/03 15:42:53 Pinger listening at [::]:5300

Start Stub in Rails

server $ bin/rails server

Ping from Browser!

http://localhost:3000/ping

Pong

{
  "pong": "pong"
}