README.md

Dubbo-go Error

1.Introduction

This sample demonstrates how to handle calling error in dubbo-go

2.Example

2.1 Server

Server Proto File

Source file path：dubbo-go-sample/error/proto/greet.proto

syntax = "proto3";

package greet;

option go_package = "github.com/apache/dubbo-go-samples/error/proto;greet";

message GreetRequest {
  string name = 1;
}

message GreetResponse {
  string greeting = 1;
}

service GreetService {
  rpc Greet(GreetRequest) returns (GreetResponse) {}
}

Server Handler File

In this program, only when the request parameter "name" accepted by the Greet function is "right name", it is considered a correct request, otherwise it is considered an error request and will not be processed and an error will be returned.

Source file path：dubbo-go-sample/context/go-server/main.go

package main

import (
	"context"
	"fmt"
	"github.com/pkg/errors"

	_ "dubbo.apache.org/dubbo-go/v3/imports"
	"dubbo.apache.org/dubbo-go/v3/protocol"
	"dubbo.apache.org/dubbo-go/v3/server"
	greet "github.com/apache/dubbo-go-samples/helloworld/proto"
	"github.com/dubbogo/gost/log/logger"
)

type GreetTripleServer struct {
}

func (srv *GreetTripleServer) Greet(ctx context.Context, req *greet.GreetRequest) (*greet.GreetResponse, error) {
	name := req.Name
	if name != "right name" {
		errInfo := fmt.Sprintf("name is not right: %s", name)
		logger.Error(errInfo)
		return nil, errors.New(errInfo)
	}

	resp := &greet.GreetResponse{Greeting: req.Name}
	return resp, nil
}

func main() {
	srv, err := server.NewServer(
		server.WithServerProtocol(
			protocol.WithPort(20000),
			protocol.WithTriple(),
		),
	)
	if err != nil {
		panic(err)
	}

	if err = greet.RegisterGreetServiceHandler(srv, &GreetTripleServer{}); err != nil {
		panic(err)
	}

	if err = srv.Serve(); err != nil {
		logger.Error(err)
	}
}

2.2 Client

The client initiates two calls respectively, one is a correct request and one is an incorrect request.

Source file path：dubbo-go-sample/context/go-client/main.go

package main

import (
	"context"

	"dubbo.apache.org/dubbo-go/v3/client"
	_ "dubbo.apache.org/dubbo-go/v3/imports"
	greet "github.com/apache/dubbo-go-samples/helloworld/proto"
	"github.com/dubbogo/gost/log/logger"
)

func main() {
	cli, err := client.NewClient(
		client.WithClientURL("127.0.0.1:20000"),
	)
	if err != nil {
		panic(err)
	}

	svc, err := greet.NewGreetService(cli)
	if err != nil {
		panic(err)
	}

	resp, err := svc.Greet(context.Background(), &greet.GreetRequest{Name: "right name"})
	if err != nil {
		logger.Error(err)
	}
	logger.Infof("call Greet success: %s", resp.Greeting)

	resp, err = svc.Greet(context.Background(), &greet.GreetRequest{Name: "wrong name"})
	if err != nil {
		logger.Errorf("call Greet failed, err: %s", err.Error())
	}
}

2.3 Example Output

Start the server first, and then the client. We can observe that the first call is successful, but the second call fails and the server returns an error.

2024-02-28 17:49:40	INFO	logger/logging.go:42	call Greet success: [right name]
2024-02-28 17:49:40	ERROR	logger/logging.go:52	call Greet failed, err: [Failed to invoke the method Greet in the service greet.GreetService. Tried 2 times of the providers [tri://:@127.0.0.1:20000/?interface=greet.GreetService&group=&version= tri://:@127.0.0.1:20000/?interface=greet.GreetService&group=&version= tri://:@127.0.0.1:20000/?interface=greet.GreetService&group=&version=] (3/1)from the registry tri://127.0.0.1:20000/greet.GreetService?app.version=&application=dubbo.io&async=false&bean.name=greet.GreetService&cluster=failover&config.tracing=&environment=&generic=&group=&interface=greet.GreetService&loadbalance=&metadata-type=local&module=sample&name=dubbo.io&organization=dubbo-go&owner=dubbo-go&peer=true&provided-by=&reference.filter=cshutdown&registry.role=0&release=dubbo-golang-3.2.0&remote.timestamp=&retries=&serialization=protobuf&side=consumer&sticky=false&timestamp=1709113780&version= on the consumer 30.221.146.234 using the dubbo version 3.2.0. Last error is unknown: name is not right: wrong name.: unknown: name is not right: wrong name]