example/outlier/hello_kratos/client/client.go

package main

import (
	"context"
	"log"
	"time"

	pb "github.com/go-kratos/examples/helloworld/helloworld"
	"github.com/go-kratos/kratos/contrib/registry/etcd/v2"
	"github.com/go-kratos/kratos/v2/metadata"
	"github.com/go-kratos/kratos/v2/selector"
	"github.com/go-kratos/kratos/v2/selector/wrr"
	"github.com/go-kratos/kratos/v2/transport/grpc"
	clientv3 "go.etcd.io/etcd/client/v3"

	sentinel "github.com/alibaba/sentinel-golang/api"
	"github.com/alibaba/sentinel-golang/core/circuitbreaker"
	"github.com/alibaba/sentinel-golang/core/outlier"
	"github.com/alibaba/sentinel-golang/pkg/adapters/kratos"
)

const serviceName = "example.helloworld"
const etcdAddr = "127.0.0.1:2379"

func initOutlierClient() pb.GreeterClient {
	// new discovery with etcd client
	client, err := clientv3.New(clientv3.Config{
		Endpoints: []string{etcdAddr},
	})
	if err != nil {
		log.Fatal(err)
	}
	etcdReg := etcd.New(client)

	// Due to the limitations of the gRPC framework, selector can
	// only be injected using a global balancer.
	selector.SetGlobalSelector(wrr.NewBuilder())

	endpoint := "discovery:///" + serviceName
	conn, err := grpc.DialInsecure(
		context.Background(),
		grpc.WithEndpoint(endpoint),
		grpc.WithDiscovery(etcdReg),
		grpc.WithNodeFilter(kratos.OutlierClientFilter),
		grpc.WithMiddleware(kratos.SentinelClientMiddleware(
			kratos.WithEnableOutlier(func(ctx context.Context) bool {
				return true
			}))),
	)
	if err != nil {
		log.Fatal(err)
	}
	return pb.NewGreeterClient(conn)
}

func main() {
	c := initOutlierClient()
	err := sentinel.InitDefault()
	if err != nil {
		log.Fatal(err)
	}
	_, err = outlier.LoadRules([]*outlier.Rule{
		{
			Rule: &circuitbreaker.Rule{
				Resource:         serviceName,
				Strategy:         circuitbreaker.ErrorCount,
				RetryTimeoutMs:   3000,
				MinRequestAmount: 1,
				StatIntervalMs:   1000,
				Threshold:        1.0,
			},
			EnableActiveRecovery: false,
			MaxEjectionPercent:   1.0,
			RecoveryIntervalMs:   2000,
			MaxRecoveryAttempts:  5,
		},
	})
	if err != nil {
		log.Fatal(err)
	}
	passCount, testCount := 0, 200
	req := &pb.HelloRequest{Name: "Bob"}
	for i := 0; i < testCount; i++ {
		ctx := metadata.NewClientContext(context.Background(), metadata.New())
		rsp, err := c.SayHello(ctx, req)
		log.Println(rsp, err)
		if err == nil {
			passCount++
		}
		time.Sleep(500 * time.Millisecond)
	}
	log.Printf("Results: %d out of %d requests were successful\n", passCount, testCount)
}