update README

Author: codeandcode0x

README.md

@@ -134,38 +134,7 @@ newRpcServiceReq(tracer)
 ```
 
 ### Http to gRPC tracing
-```go
-//grpc request
-func RpcClient(ptx context.Context) string {
-	rpcOption, closer := tracing.AddRpcClientTracing(
-		"RpcClient",
-		map[string]string{"version": "v1"})
-    // or map[string]string{"traceType": "zipkin", "version": "v1"}), traceType : jaeger (default) or zipkin
-	// or export TRACE_TYPE=zipkin or jaeger
-	defer closer.Close()
-	address := "localhost:22530"
-	conn, err := grpc.Dial(address, grpc.WithInsecure(), rpcOption)
-	if err != nil {
-	}
-	defer conn.Close()
-	c := pb.NewGreeterClient(conn)
-	// Contact the server and print out its response.
-	name := "rpc test"
-	if len(os.Args) > 1 {
-		name = os.Args[1]
-	}
-	// use parent context
-	ctx, cancel := context.WithTimeout(ptx, time.Second)
-	defer cancel()
-	r, err := c.SayHello(ctx, &pb.HelloRequest{Name: name})
-	if err != nil {
-		log.Println("error:", err)
-	}
-
-	log.Printf("Greeting: %s", r.Message)
-	return r.Message
-}
-```
+![http to grpc client](wiki/imgs/httptogrpc_client.jpg)
 **ptx** is parent context, it can create sub-context trace span <br>
 To call gRPC on the http server side, you need to add the parent context to the gRPC client. For details, you can see the [example](example/http/httpServer.go) .
 

example/http/httpServer.go

@@ -38,6 +38,8 @@ func RpcClient(ptx context.Context) string {
 	rpcOption, closer := tracing.AddRpcClientTracing(
 		"RpcClient",
 		map[string]string{"version": "v1"})
+	// or map[string]string{"traceType": "zipkin", "version": "v1"}), traceType : jaeger (default) or zipkin
+	// or export TRACE_TYPE=zipkin or jaeger
 	defer closer.Close()
 	address := "localhost:22530"
 	conn, err := grpc.Dial(address, grpc.WithInsecure(), rpcOption)