grpc中间件之链路追踪（otel+jaeger）

package main
 
import (
    "context"
    "fmt"
    "log"
    "net/http"
    
    "go.opentelemetry.io/otel"
    "go.opentelemetry.�ser/jaeger"
    "go.opentelemetry.io/otel/attribute"
    "go.opentelemetry.io/otel/baggage"
    "go.opentelemetry.io/otel/propagation"
    sdktrace "go.opentelemetry.io/otel/sdk/trace"
    "go.opentelemetry.io/otel/trace"
    
    grpctrace "go.opentelemetry.io/otel/plugin/grpctrace"
    "google.golang.org/grpc"
    "google.golang.org/grpc/credentials" // 如果使用了安全连接，需要这个包
)
 
func initTracer(service string) {
    // 创建 Jaeger Tracer
    exp, err := jaeger.New(service)
    if err != nil {
        log.Panicf("cannot init Jaeger: %v", err)
    }
    tp := sdktrace.NewTracerProvider(
        sdktrace.WithSampler(sdktrace.AlwaysSample()),
        sdktrace.WithBatcher(exp),
    )
    otel.SetTracerProvider(tp)
    otel.SetTextMapPropagator(propagation.NewCompositeTextMapPropagator(
        propagation.TraceContext{},
        propagation.Baggage{},
    ))
}
 
func main() {
    initTracer("my-service")
    
    // 使用上面初始化的Tracer，这里可以添加更多的span和trace信息
    ctx, span := otel.Tracer("my-service").Start(context.Background(), "main")
    defer span.End()
    
    // 创建gRPC客户端
    conn, err := grpc.DialContext(ctx, "example.com:50051",
        grpc.WithTransportCredentials(credentials.NewClientTLSFromCert(nil, "")),
        grpc.WithUnaryInterceptor(grpctrace.UnaryClientInterceptor()),
        grpc.WithStreamInterceptor(grpctrace.StreamClientInterceptor()),
    )
    if err != nil {
        log.Fatalf("did not connect: %v", err)
    }
    defer conn.Close()
    
    // 假设有一个gRPC服务的客户端方法
    client := NewGreeterClient(conn)
    response, err := client.SayHello(ctx, &HelloRequest{Name: "world"})
    if err != nil {
        log.Fatalf("could not greet: %v", err)
    }
    
    fmt.Printf("Greeting: %s\n", response.Message)
}

这个代码示例展示了如何在Go语言中使用OpenTelemetry和Jaeger来追踪gRPC服务的客户端请求。首先，我们初始化了一个Jaeger Tracer，并设置了全局的TracerProvider和TextMapPropagator。然后，在发起gRPC请求时，我们通过UnaryClientInterceptor和StreamClientInterceptor添加了opentelemetry的追踪。最后，我们发送了一个gRPC请求，并对收到的响应进行了打印。