skywalking 跟踪grpc的链路

skywalking对http请求实现了无代码入侵的跟踪，但是对grpc则需要修改相应的代码。

根据官方的提示：

https://github.com/SkyAPM/SkyAPM-dotnet/pull/236

1.由于Grpc没有Diagnostics机制，只能通过它本身提供的Interceptor拦截器去实现追踪，因此貌似没有办法做到代码无浸入，必须要注入该追踪拦截器
2.Grpc客户端需要在new Channel().Intercept()中传入ClientDiagnosticInterceptor实例对象
3.Grpc服务端需要在start()服务之前传入ServerDiagnosticInterceptor实例对象
详情可以参考示例代码，效果截图

以及官方提供的demo,我们在grpc的客户端代码进行调整：

1、构造函数注入一个拦截器 ClientDiagnosticInterceptor interceptor 

2、构造函数创建client  ，并且将该拦截器添加进来。

3、具体的代码如下，里面包含了 grpc和http这2种类型的简单实现。

    [ApiController]
    [Route("api/[controller]/[action]")]
    public class WeatherForecastController : ControllerBase
    {

        private readonly IHttpClientFactory _clientFactory;
        private readonly ILogger<WeatherForecastController> _logger;

        private readonly Greeter.GreeterClient _client;
        public WeatherForecastController(ClientDiagnosticInterceptor interceptor,ILogger<WeatherForecastController> logger, IHttpClientFactory clientFactory)
        {
            _logger = logger;
            _clientFactory = clientFactory; 
            var target = "localhost:5000";
            var channel = new Channel(target, ChannelCredentials.Insecure);
            var invoker = channel.Intercept(interceptor);
            _client = new Greeter.GreeterClient(invoker).WithHost(target);

        }

        [HttpGet]
        public async  Task<IActionResult>  GetGrpc()
        {  

            try
            { 
                var reply = _client.SayHello(new HelloRequest { Name = "晓晨222" });
                 
                Console.WriteLine("Greeter 服务返回数据: " + reply.Message);
            }
            catch (Exception ex)
            {
                int i = 0;

            }

          


            return Ok("ok啦");
             
        }

        [HttpPost]
        public async Task<IActionResult> PostHttp()
        {
            var request = new HttpRequestMessage(HttpMethod.Get,
           "http://10.10.1.204:31927/api/Health/Get");
            request.Headers.Add("Accept", "application/vnd.github.v3+json");
            request.Headers.Add("User-Agent", "HttpClientFactory-Sample");

            var client = _clientFactory.CreateClient();

            var response = await client.SendAsync(request);

            if (response.IsSuccessStatusCode)
            {
                return Ok(response.Content.ReadAsStringAsync());
            }
            else
            {
                return Ok("error000001");

            } 

            return Ok("ok-post啦");

        }
    }