生产环境调用Bing地图API随机出现连接超时异常求助

背景 #

应用已部署到生产服务器，通过并发调用Bing地图API（地址：https://dev.virtualearth.net/REST/v1/Locations）批量获取位置数据，运行基本正常，但会随机出现连接超时异常，影响稳定性。

调用代码 #

private async Task<BingResponse> GetBingResponse(string argUri)
{
    try
    {
        WebRequest request = HttpWebRequest.Create(new Uri(argUri));
        var response = await request.GetResponseAsync();

        if (((HttpWebResponse)response).StatusCode == HttpStatusCode.OK)
        {
            using (Stream resStream = (response.GetResponseStream()))
            {
                DataContractJsonSerializer jsonData = new DataContractJsonSerializer(typeof(BingResponse));
                return jsonData.ReadObject(resStream) as BingResponse;
            }
        }
        else
            return null;
    }
    catch (Exception ex)
    {
        XLLogger.Write("Exception with BingResponse URL");
        return null;
    }
}

异常详情（含中文翻译） #

原始异常信息 #

{
    "ClassName": "System.Net.WebException",
    "Message": "A connection attempt failed because the connected party did not properly respond after a period of time, or established connection failed because connected host has failed to respond. (dev.virtualearth.net:443)",
    "Data": null,
    "InnerException": {
        "StatusCode": null,
        "Message": "A connection attempt failed because the connected party did not properly respond after a period of time, or established connection failed because connected host has failed to respond. (dev.virtualearth.net:443)",
        "Data": {},
        "InnerException": {
            "ClassName": "System.Net.Sockets.SocketException",
            "Message": "A connection attempt failed because the connected party did not properly respond after a period of time, or established connection failed because connected host has failed to respond.",
            "Data": null,
            "InnerException": null,
            "HelpURL": null,
            "StackTraceString": "   at System.Net.Sockets.Socket.AwaitableSocketAsyncEventArgs.System.Threading.Tasks.Sources.IValueTaskSource.GetResult(Int16 token)\r\n   at System.Net.Sockets.Socket.<ConnectAsync>g__WaitForConnectWithCancellation|277_0(AwaitableSocketAsyncEventArgs saea, ValueTask connectTask, CancellationToken cancellationToken)\r\n   at System.Net.HttpWebRequest.<>c__DisplayClass216_0.<CreateHttpClient>b__1>d.MoveNext()\r\n--- End of stack trace from previous location ---\r\n   at System.Net.Http.HttpConnectionPool.ConnectToTcpHostAsync(String host, Int32 port, HttpRequestMessage initialRequest, Boolean async, CancellationToken cancellationToken)",
            "RemoteStackTraceString": null,
            "RemoteStackIndex": 0,
            "ExceptionMethod": null,
            "HResult": -2147467259,
            "Source": "System.Net.Sockets",
            "WatsonBuckets": null,
            "NativeErrorCode": 10060
        },
        "HelpLink": null,
        "Source": "System.Net.Http",
        "HResult": -2147467259,
        "StackTrace": "   at System.Net.Http.HttpConnectionPool.ConnectToTcpHostAsync(String host, Int32 port, HttpRequestMessage initialRequest, Boolean async, CancellationToken cancellationToken)\r\n   at System.Net.Http.HttpConnectionPool.ConnectAsync(HttpRequestMessage request, Boolean async, CancellationToken cancellationToken)\r\n   at System.Net.Http.HttpConnectionPool.CreateHttp11ConnectionAsync(HttpRequestMessage request, Boolean async, CancellationToken cancellationToken)\r\n   at System.Net.Http.HttpConnectionPool.AddHttp11ConnectionAsync(HttpRequestMessage request)\r\n   at System.Threading.Tasks.TaskCompletionSourceWithCancellation`1.WaitWithCancellationAsync(CancellationToken cancellationToken)\r\n   at System.Net.Http.HttpConnectionPool.GetHttp11ConnectionAsync(HttpRequestMessage request, Boolean async, CancellationToken cancellationToken)\r\n   at System.Net.Http.HttpConnectionPool.SendWithVersionDetectionAndRetryAsync(HttpRequestMessage request, Boolean async, Boolean doRequestAuth, CancellationToken cancellationToken)\r\n   at System.Net.Http.DiagnosticsHandler.SendAsyncCore(HttpRequestMessage request, Boolean async, CancellationToken cancellationToken)\r\n   at System.Net.Http.RedirectHandler.SendAsync(HttpRequestMessage request, Boolean async, CancellationToken cancellationToken)\r\n   at System.Net.Http.HttpClient.<SendAsync>g__Core|83_0(HttpRequestMessage request, HttpCompletionOption completionOption, CancellationTokenSource cts, Boolean disposeCts, CancellationTokenSource pendingRequestsCts, CancellationToken originalCancellationToken)\r\n   at System.Net.HttpWebRequest.SendRequest(Boolean async)\r\n   at System.Net.HttpWebRequest.EndGetResponse(IAsyncResult asyncResult)"
    },
    "HelpURL": null,
    "StackTraceString": "   at System.Net.HttpWebRequest.EndGetResponse(IAsyncResult asyncResult)\r\n   at System.Threading.Tasks.TaskFactory`1.FromAsyncCoreLogic(IAsyncResult iar, Func`2 endFunction, Action`1 endAction, Task`1 promise, Boolean requiresSynchronization)\r\n--- End of stack trace from previous location ---\r\n",
    "RemoteStackTraceString": null,
    "RemoteStackIndex": 0,
    "ExceptionMethod": null,
    "HResult": -2147467259,
    "Source": "System.Net.Requests",
    "WatsonBuckets": null
}

中文翻译 #

• 顶层异常：System.Net.WebException：连接尝试失败，因为连接方在一段时间后未正确响应，或已建立的连接因目标主机未响应而失败。(dev.virtualearth.net:443)
• 内层Socket异常：System.Net.Sockets.SocketException（错误码10060）：连接尝试失败，因为连接方在一段时间后未正确响应，或已建立的连接因目标主机未响应而失败。

解决方案 #

• 添加超时控制：给HttpWebRequest设置合理的超时时间，避免无限制等待。比如在创建请求后加：

  ((HttpWebRequest)request).Timeout = 10000; // 10秒超时
  ((HttpWebRequest)request).ReadWriteTimeout = 15000; // 读写超时15秒
  

• 实现重试策略：针对连接超时这类临时异常，用指数退避法重试，最多3次，间隔依次为1秒、2秒、4秒，避免单次失败直接返回。
• 替换为HttpClient：HttpWebRequest是旧API，HttpClient自带连接池，更适合并发场景，能减少连接资源浪费。示例：

  private static readonly HttpClient _httpClient = new HttpClient();
  private async Task<BingResponse> GetBingResponse(string argUri)
  {
      try
      {
          var response = await _httpClient.GetAsync(argUri);
          if (response.IsSuccessStatusCode)
          {
              var json = await response.Content.ReadAsStringAsync();
              // 用JsonSerializer反序列化，替换DataContractJsonSerializer
              return JsonSerializer.Deserialize<BingResponse>(json);
          }
          return null;
      }
      catch (Exception ex)
      {
          XLLogger.Write($"Exception with BingResponse URL: {ex.Message}");
          return null;
      }
  }
  

• 限制并发量：Bing API有调用配额，并发太高可能被限流或导致自身连接池耗尽。用SemaphoreSlim控制并发数，比如限制同时发送10个请求：

  private static readonly SemaphoreSlim _semaphore = new SemaphoreSlim(10);
  // 在调用GetBingResponse前：
  await _semaphore.WaitAsync();
  try
  {
      var result = await GetBingResponse(uri);
      // 处理结果
  }
  finally
  {
      _semaphore.Release();
  }
  

• 排查网络问题：确认生产服务器到dev.virtualearth.net的网络是否稳定，有无防火墙、代理拦截，可通过ping、telnet测试连通性。

内容的提问来源于stack exchange，提问作者Vignesh Kumar A