This sample demonstrates how to use retry feature in Dubbo-go.
When creating a client with client.NewClient(), you can use client.WithClientRetries() to set the number of retries.
cli, err := client.NewClient(
client.WithClientURL("tri://127.0.0.1:20000"),
client.WithClientRetries(3),
)Source file path: dubbo-go-sample/retry/proto/greet.proto
syntax = "proto3";
package greet;
option go_package = "github.com/apache/dubbo-go-samples/timeout/proto;greet";
message GreetRequest {
string name = 1;
}
message GreetResponse {
string greeting = 1;
}
service GreetService {
rpc Greet(GreetRequest) returns (GreetResponse) {}
rpc GreetTimeout(GreetRequest) returns (GreetResponse) {}
}The Greet method responds directly, and the GreetRetry method is used to simulate retries.
package main
import (
"context"
"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/retry/proto"
"github.com/dubbogo/gost/log/logger"
)
type GreetTripleServer struct {
requestTime int
}
func (srv *GreetTripleServer) Greet(ctx context.Context, req *greet.GreetRequest) (*greet.GreetResponse, error) {
resp := &greet.GreetResponse{Greeting: req.Name}
logger.Info("Not need retry, request success")
return resp, nil
}
func (srv *GreetTripleServer) GreetRetry(ctx context.Context, req *greet.GreetRequest) (*greet.GreetResponse, error) {
if srv.requestTime < 3 {
srv.requestTime++
logger.Infof("retry %d times", srv.requestTime)
return nil, errors.New("retry")
}
resp := &greet.GreetResponse{Greeting: req.Name}
logger.Infof("retry success, current request time is %d", srv.requestTime)
srv.requestTime = 0
return resp, nil
}
func main() {
srv, err := server.NewServer(
server.WithServerProtocol(
protocol.WithPort(20000),
),
)
if err != nil {
panic(err)
}
if err := greet.RegisterGreetServiceHandler(srv, &GreetTripleServer{
requestTime: 0,
}); err != nil {
panic(err)
}
if err := srv.Serve(); err != nil {
logger.Error(err)
}
}Client file, create client, set retry times to 3, request Greet and GreetRetry respectively, and observe the server log output.
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/retry/proto"
"github.com/dubbogo/gost/log/logger"
)
func main() {
cli, err := client.NewClient(
client.WithClientURL("tri://127.0.0.1:20000"),
client.WithClientRetries(3),
)
if err != nil {
panic(err)
}
svc, err := greet.NewGreetService(cli)
if err != nil {
panic(err)
}
// request normal
resp, err := svc.Greet(context.Background(), &greet.GreetRequest{Name: "hello world"})
if err != nil {
logger.Error(err)
}
logger.Infof("Greet response: %s", resp.Greeting)
// request need retry
resp, err = svc.GreetRetry(context.Background(), &greet.GreetRequest{Name: "hello world"})
if err != nil {
logger.Error(err)
}
logger.Infof("Greet response: %s", resp.Greeting)
}First start the server, then start the client, and observe that the server log outputs the number of retries when accessing GreetRetry.
2024-01-23 22:39:11 INFO logger/logging.go:22 [Not need retry, request success]
2024-01-23 22:39:11 INFO logger/logging.go:42 retry [1] times
2024-01-23 22:39:11 INFO logger/logging.go:42 retry [2] times
2024-01-23 22:39:11 INFO logger/logging.go:42 retry [3] times
2024-01-23 22:39:11 INFO logger/logging.go:42 retry success, current request time is [3]