Writing gRPC service¶
Checkout full example in [here](https://github.com/go-chassis/go-chassis-examples/tree/master/grpc) ### Define grpc contract 1个工程或者go package，推荐结构如下 ``` schemas `– helloworld
`– helloworld.proto
1.定义helloworld.proto文件 ```proto syntax = “proto3”;
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;
}
`
2.通过pb生成go文件 helloworld.pb.go
```bash
protoc --go_out=plugins=grpc:. helloworld.proto
`
将生成的go文件拷贝到目录中
After generated, need to change one variable name ```go var _Greeter_serviceDesc = grpc.ServiceDesc{
ServiceName: “helloworld.Greeter”, // use this as the schemaID when consumer call provider HandlerType: (*GreeterServer)(nil), Methods: []grpc.MethodDesc{
- {
MethodName: “SayHello”, Handler: _Greeter_SayHello_Handler,
},
}, Streams: []grpc.StreamDesc{}, Metadata: “helloworld.proto”,
}¶
change _Greeter_serviceDesc to Greeter_serviceDesc
### Provider Side
1个工程或者go package，推荐结构如下
`
server
|-- conf
| |-- chassis.yaml
| `-- microservice.yaml
`-- main.go
`
1.编写接口 ```go type Server struct{}
// SayHello implements helloworld.GreeterServer func (s *Server) SayHello(ctx context.Context, in *pb.HelloRequest) (*pb.HelloReply, error) {
return &pb.HelloReply{Message: “Hello ” + in.Name}, nil
}¶
2.注册接口
第一个参数表示你要向哪个协议注册，第三个为grpc serivce desc
`go
chassis.RegisterSchema("grpc", &Server{}, server.WithRPCServiceDesc(&pb.Greeter_serviceDesc))
`
3.修改配置文件chassis.yaml ```yaml servicecomb:
- registry:
address: http://127.0.0.1:30100
- protocols:
- grpc:
listenAddress: 127.0.0.1:5000
``` 4.修改microservice.yaml ```yaml servicecomb:
- service:
name: RPCServer
`
5.In main.go import grpc server to enable grpc protocol and start go chassis
```go
import _ "github.com/go-chassis/go-chassis-extension/grpc/server"
`
//start all server you register in server/schemas. if err := chassis.Init(); err != nil {
lager.Logger.Errorf(“Init failed: %s”, err) return
} chassis.Run()
}¶
### Consumer Side
1个工程或者go package，推荐结构如下
`
client
|-- conf
| |-- chassis.yaml
| `-- microservice.yaml
`-- main.go
`
1.修改配置文件chassis.yaml ```yaml servicecomb:
- registry:
address: http://127.0.0.1:30100
2.修改microservice.yaml ```yaml servicecomb:
- service:
name: Client
3.5.In main.go import grpc client to enable grpc protocol.
`go
import _ "github.com/go-chassis/go-chassis-extension/grpc/client"
`
Use invoker to call remote function ```go //if you use go run main.go instead of binary run, plz export CHASSIS_HOME=/path/to/conf/folder func main() { //Init framework
- if err := chassis.Init(); err != nil {
lager.Logger.Error(“Init failed.” + err.Error()) return
} //declare reply struct reply := &helloworld.HelloReply{} //Invoke with microservice name, schema ID and operation ID if err := core.NewRPCInvoker().Invoke(context.Background(), “RPCServer”, “helloworld.Greeter”, “SayHello”,
&helloworld.HelloRequest{Name: “Peter”}, reply, core.WithProtocol(“grpc”)); err != nil { lager.Logger.Error(“error” + err.Error())
} lager.Logger.Info(reply.Message)
}¶
Notice >> if conf folder is not under work dir, plz export CHASSIS_HOME=/path/to/conf/parent_folder or CHASSIS_CONF_DIR==/path/to/conf_folder