kratos/examples/traces/app/user/main.go

package main

import (
	"context"
	"os"
	"time"

	messagev1 "github.com/go-kratos/kratos/examples/traces/api/message"
	v1 "github.com/go-kratos/kratos/examples/traces/api/user"
	"github.com/go-kratos/kratos/v2"
	"github.com/go-kratos/kratos/v2/log"
	"github.com/go-kratos/kratos/v2/middleware/logging"
	"github.com/go-kratos/kratos/v2/middleware/recovery"
	"github.com/go-kratos/kratos/v2/middleware/tracing"
	"github.com/go-kratos/kratos/v2/transport/grpc"
	"github.com/go-kratos/kratos/v2/transport/http"

	"go.opentelemetry.io/otel"
	"go.opentelemetry.io/otel/attribute"
	"go.opentelemetry.io/otel/exporters/jaeger"
	"go.opentelemetry.io/otel/sdk/resource"
	tracesdk "go.opentelemetry.io/otel/sdk/trace"
	semconv "go.opentelemetry.io/otel/semconv/v1.4.0"
	grpcx "google.golang.org/grpc"
)

// go build -ldflags "-X main.Version=x.y.z"
var (
	// Name is the name of the compiled software.
	Name = "user"
	// Version is the version of the compiled software.
	Version = "v1.0.0"
)

// server is used to implement helloworld.GreeterServer.
type server struct {
	v1.UnimplementedUserServer
}

// Set global trace provider
func setTracerProvider(url string) error {
	// Create the Jaeger exporter
	exp, err := jaeger.New(jaeger.WithCollectorEndpoint(jaeger.WithEndpoint(url)))
	if err != nil {
		return err
	}
	tp := tracesdk.NewTracerProvider(
		// Set the sampling rate based on the parent span to 100%
		tracesdk.WithSampler(tracesdk.ParentBased(tracesdk.TraceIDRatioBased(1.0))),
		// Always be sure to batch in production.
		tracesdk.WithBatcher(exp),
		// Record information about this application in an Resource.
		tracesdk.WithResource(resource.NewSchemaless(
			semconv.ServiceNameKey.String(Name),
			attribute.String("env", "dev"),
		)),
	)
	otel.SetTracerProvider(tp)
	return nil
}

func (s *server) GetMyMessages(ctx context.Context, in *v1.GetMyMessagesRequest) (*v1.GetMyMessagesReply, error) {
	// create grpc conn
	// only for demo, use single instance in production env
	conn, err := grpc.DialInsecure(ctx,
		grpc.WithEndpoint("127.0.0.1:9000"),
		grpc.WithMiddleware(
			recovery.Recovery(),
			tracing.Client(),
		),
		grpc.WithTimeout(2*time.Second),
		// for tracing remote ip recording
		grpc.WithOptions(grpcx.WithStatsHandler(&tracing.ClientHandler{})),
	)
	if err != nil {
		return nil, err
	}
	msg := messagev1.NewMessageServiceClient(conn)
	// Method of calling blog service
	reply, err := msg.GetUserMessage(ctx, &messagev1.GetUserMessageRequest{Id: 123, Count: in.Count})
	if err != nil {
		return nil, err
	}
	res := &v1.GetMyMessagesReply{}
	for _, v := range reply.Messages {
		res.Messages = append(res.Messages, &v1.Message{Content: v.Content})
	}
	return res, nil
}

func main() {
	logger := log.NewStdLogger(os.Stdout)
	logger = log.With(logger, "trace_id", tracing.TraceID())
	logger = log.With(logger, "span_id", tracing.SpanID())
	log := log.NewHelper(logger)

	url := "http://jaeger:14268/api/traces"
	if os.Getenv("jaeger_url") != "" {
		url = os.Getenv("jaeger_url")
	}
	err := setTracerProvider(url)
	if err != nil {
		log.Error(err)
	}

	httpSrv := http.NewServer(
		http.Address(":8000"),
		http.Middleware(
			recovery.Recovery(),
			tracing.Server(),
			logging.Server(logger),
		),
	)
	s := &server{}
	v1.RegisterUserHTTPServer(httpSrv, s)

	app := kratos.New(
		kratos.Name(Name),
		kratos.Server(
			httpSrv,
		),
	)

	if err := app.Run(); err != nil {
		log.Error(err)
	}
}