C# 结合使用HttpClient和NServiceBus的严重延迟

我正在使用NServiceBus进行集成POC。此集成在发生事件时向API发出通知

这一切都是可行的，但当执行并发http请求时，会出现严重的性能问题

我配置了一个端点，它完成一件事：向RESTAPI发送json请求（通知）

我的设置：

端点（framework 4.6.1）有一个静态HttpClient，在程序启动时只初始化一次：

internal static void Intitialize()
        {
            ServicePointManager.DefaultConnectionLimit = 100;
            var apiSettings = NotificationEngineManager.GetInterfaceSettings()?.API;
            NotificationClient = new HttpClient();
            NotificationClient.Timeout = TimeSpan.FromSeconds(45);
            if (!string.IsNullOrEmpty(apiSettings.UserName))
            {
                var byteArray = Encoding.ASCII.GetBytes($"{apiSettings.UserName}:{apiSettings.Password}");
                NotificationClient.DefaultRequestHeaders.Authorization = new AuthenticationHeaderValue("Basic", Convert.ToBase64String(byteArray));
            }
        }

        internal static HttpClient NotificationClient { get; set; }

负责发布请求的我的处理人：

   public async Task Handle(EventRegistered message, IMessageHandlerContext context)
            {
                var apiSettings = NotificationEngineManager.GetInterfaceSettings()?.API;
                if (apiSettings == null)
                {
                    throw new BusinessException("No valid API settings found");
                }

                JsonSerializerSettings settings = new JsonSerializerSettings();
                settings.NullValueHandling = NullValueHandling.Ignore;
                settings.DateFormatString = "s";
                settings.Converters.Add(new StringEnumConverter { });


                try
                {
                    var jsonRequest = JsonConvert.SerializeObject(message.Notification, settings);
                    var response = await HttpClients.NotificationClient.PostAsync(apiSettings.Endpoint, new StringContent(jsonRequest, Encoding.UTF8, "application/json"));
                    response.EnsureSuccessStatusCode();
                }
                catch (TaskCanceledException)
                {
                    throw new Exception("Notifiaction Request timed out.");
                }

                await context.Publish(new NotificationSent(message, DateTime.Now)).ConfigureAwait(false);

}

问题：

NServiceBus端点同时处理10条消息，这意味着同时处理10个http post请求

RESTAPI大约需要0.2秒来响应1条消息。但同时触发10个HTTPPOST请求大约需要35秒。 所有请求都在同一时间开始，但也都在同一时间结束，大约35秒后

使用

netstat

命令，我可以看到10个打开的到API的tcp连接。因此，HttpClient确实处理并发请求

奇怪的是，如果我将端点并发性设置为1，这意味着http请求是1对1处理的，那么所有10个请求都在2秒内处理完毕

如果我将端点并发级别设置为20或更多，几乎所有请求都会超时（超时=45秒）

可以使用HttpWebRequest而不是HttpClient复制相同的内容

我在这里不知所措。我错过了什么？看起来所有的请求都被删除了 在客户端或服务器上互相等待。任何帮助都是无效的 非常感谢

RESTAPI是运行在ISS（非express）上的基本.NET核心API

服务器端日志记录。 日志中间件添加到管道的开头

2018-04-18 09:05:38.7660 INFO Begin Request 6
2018-04-18 09:05:38.7850 INFO message 6 received
2018-04-18 09:05:38.8150 INFO End Request 6
2018-04-18 09:05:39.4036 INFO Begin Request 9
2018-04-18 09:05:39.4231 INFO message 9 received
2018-04-18 09:05:39.4551 INFO End Request 9
2018-04-18 09:05:39.7172 INFO Begin Request 10
2018-04-18 09:05:39.7512 INFO message 10 received
2018-04-18 09:05:39.7512 INFO Begin Request 8
2018-04-18 09:05:39.7812 INFO End Request 10
2018-04-18 09:05:39.8132 INFO message 8 received
2018-04-18 09:05:39.8302 INFO End Request 8
2018-04-18 09:05:40.0722 INFO Begin Request 1
2018-04-18 09:05:40.1097 INFO message 1 received
2018-04-18 09:05:40.1097 INFO Begin Request 5
2018-04-18 09:05:40.1413 INFO message 5 received
2018-04-18 09:05:40.1703 INFO End Request 1
2018-04-18 09:05:40.1913 INFO End Request 5
2018-04-18 09:05:40.4033 INFO Begin Request 3
2018-04-18 09:05:40.4403 INFO message 3 received
2018-04-18 09:05:40.4563 INFO End Request 3
2018-04-18 09:05:40.5173 INFO Begin Request 7
2018-04-18 09:05:40.5508 INFO message 7 received
2018-04-18 09:05:40.5663 INFO End Request 7
2018-04-18 09:05:41.0100 INFO Begin Request 4
2018-04-18 09:05:41.0470 INFO message 4 received
2018-04-18 09:05:41.0630 INFO End Request 4
2018-04-18 09:05:41.3535 INFO Begin Request 2
2018-04-18 09:05:41.3740 INFO message 2 received
2018-04-18 09:05:41.4080 INFO End Request 2

看看请求8。

---

请求是在代码.23中启动的。服务器在.39收到请求。因此有16秒的间隔。

我使用System.Diagnostics和NLog记录了网络跟踪。 这导致了严重的性能下降

---

禁用System.Diagnostics解决了我的问题。

这真的是REST API正在做的唯一事情吗？另外，您能否共享您的NServiceBus端点配置和代码初始化？如何测量表中的开始/停止值？我怀疑问题在于跨消息共享静态变量（HttpClient）。为什么不为每条消息创建一个HttpClient？@RamonSmits:是的，API实际上什么也不做，只是返回一个消息。开始时间是拾取消息的时间。停止时间是收到响应的时间。从我的网络跟踪中，我注意到所有请求都是一起生成的，并且都是同时发送的。发送部分大约在15秒后发生。请告诉我您在哪里禁用了System.Diagnostics。我在NServicebus、基于asp.net核心的端点和SQSTransport方面面临着完全相同的问题。我在使用System.net.Http跟踪httpRequest时也面临着同样的问题。我从System.Diagnostic配置文件中删除了跟踪。我现在添加了一个额外的HttpClientHandler来处理日志记录。在我的例子中，我使用的是我调用的开发环境http端点，但响应太慢。有一次，我切换到staging one，它开始流动：）

    log.Info($"Start request {message.Event.Id.ToString()}");
                    var response = await HttpClients.NotificationClient.PostAsync(apiSettings.Endpoint, new StringContent(jsonRequest, Encoding.UTF8, "application/json"));              
                    response.EnsureSuccessStatusCode();
                    log.Info($"Stop request {message.Event.Id.ToString()}");

2018-04-18 09:05:23.2886 INFO NOTIFY_WO_OUT 8 Start request
2018-04-18 09:05:23.2886 INFO NOTIFY_WO_OUT 10 Start request
2018-04-18 09:05:23.2886 INFO NOTIFY_WO_OUT 5 Start request
2018-04-18 09:05:23.2886 INFO NOTIFY_WO_OUT 2 Start request
2018-04-18 09:05:23.2886 INFO NOTIFY_WO_OUT 4 Start request
2018-04-18 09:05:23.6336 INFO NOTIFY_WO_OUT 6 Start request
2018-04-18 09:05:24.6329 INFO NOTIFY_WO_OUT 9 Start request
2018-04-18 09:05:25.6142 INFO NOTIFY_WO_OUT 1 Start request
2018-04-18 09:05:26.6544 INFO NOTIFY_WO_OUT 7 Start request
2018-04-18 09:05:27.6545 INFO NOTIFY_WO_OUT 3 Start request
2018-04-18 09:05:47.2034 INFO NOTIFY_WO_OUT 5 Stop request
2018-04-18 09:05:47.6285 INFO NOTIFY_WO_OUT 3 Stop request
2018-04-18 09:05:47.9855 INFO NOTIFY_WO_OUT 6 Stop request
2018-04-18 09:05:48.0550 INFO NOTIFY_WO_OUT 9 Stop request
2018-04-18 09:05:48.5226 INFO NOTIFY_WO_OUT 4 Stop request
2018-04-18 09:05:48.5526 INFO NOTIFY_WO_OUT 10 Stop request
2018-04-18 09:05:48.9987 INFO NOTIFY_WO_OUT 8 Stop request
2018-04-18 09:05:49.0347 INFO NOTIFY_WO_OUT 1 Stop request
2018-04-18 09:05:49.0647 INFO NOTIFY_WO_OUT 7 Stop request
2018-04-18 09:05:49.3017 INFO NOTIFY_WO_OUT 2 Stop request

2018-04-18 09:05:38.7660 INFO Begin Request 6
2018-04-18 09:05:38.7850 INFO message 6 received
2018-04-18 09:05:38.8150 INFO End Request 6
2018-04-18 09:05:39.4036 INFO Begin Request 9
2018-04-18 09:05:39.4231 INFO message 9 received
2018-04-18 09:05:39.4551 INFO End Request 9
2018-04-18 09:05:39.7172 INFO Begin Request 10
2018-04-18 09:05:39.7512 INFO message 10 received
2018-04-18 09:05:39.7512 INFO Begin Request 8
2018-04-18 09:05:39.7812 INFO End Request 10
2018-04-18 09:05:39.8132 INFO message 8 received
2018-04-18 09:05:39.8302 INFO End Request 8
2018-04-18 09:05:40.0722 INFO Begin Request 1
2018-04-18 09:05:40.1097 INFO message 1 received
2018-04-18 09:05:40.1097 INFO Begin Request 5
2018-04-18 09:05:40.1413 INFO message 5 received
2018-04-18 09:05:40.1703 INFO End Request 1
2018-04-18 09:05:40.1913 INFO End Request 5
2018-04-18 09:05:40.4033 INFO Begin Request 3
2018-04-18 09:05:40.4403 INFO message 3 received
2018-04-18 09:05:40.4563 INFO End Request 3
2018-04-18 09:05:40.5173 INFO Begin Request 7
2018-04-18 09:05:40.5508 INFO message 7 received
2018-04-18 09:05:40.5663 INFO End Request 7
2018-04-18 09:05:41.0100 INFO Begin Request 4
2018-04-18 09:05:41.0470 INFO message 4 received
2018-04-18 09:05:41.0630 INFO End Request 4
2018-04-18 09:05:41.3535 INFO Begin Request 2
2018-04-18 09:05:41.3740 INFO message 2 received
2018-04-18 09:05:41.4080 INFO End Request 2