Azure NotificationHubClient 在 Azure 函数上密集使用时抛出 SocketException

Question

我们使用 Azure 函数通过 Azure NotificationHubClient 发送推送通知。这个函数在实时环境的高峰时间被调用很多，结果我们得到了很多从 NotificationHubClient.SendNotificationAsync() 方法抛出的 SocketExceptions。

异常详情：

Microsoft.Azure.NotificationHubs.Messaging.MessagingException: Unexpected exception encountered TimeStamp:2020-03-27T04:14:35.4655705Z ---> System.Net.Http.HttpRequestException: Cannot assign requested address ---> System.Net.Sockets.SocketException: Cannot assign requested address
   at System.Net.Http.ConnectHelper.ConnectAsync(String host, Int32 port, CancellationToken cancellationToken)
   --- End of inner exception stack trace ---
   at System.Net.Http.ConnectHelper.ConnectAsync(String host, Int32 port, CancellationToken cancellationToken)
   at System.Threading.Tasks.ValueTask`1.get_Result()
   at System.Net.Http.HttpConnectionPool.CreateConnectionAsync(HttpRequestMessage request, CancellationToken cancellationToken)
   at System.Threading.Tasks.ValueTask`1.get_Result()
   at System.Net.Http.HttpConnectionPool.WaitForCreatedConnectionAsync(ValueTask`1 creationTask)
   at System.Threading.Tasks.ValueTask`1.get_Result()
   at System.Net.Http.HttpConnectionPool.SendWithRetryAsync(HttpRequestMessage request, Boolean doRequestAuth, CancellationToken cancellationToken)
   at System.Net.Http.RedirectHandler.SendAsync(HttpRequestMessage request, CancellationToken cancellationToken)
   at System.Net.Http.DiagnosticsHandler.SendAsync(HttpRequestMessage request, CancellationToken cancellationToken)
   at System.Net.Http.HttpClient.FinishSendAsyncBuffered(Task`1 sendTask, HttpRequestMessage request, CancellationTokenSource cts, Boolean disposeCts)
   at Microsoft.Azure.NotificationHubs.NotificationHubClient.SendRequestAsync(HttpRequestMessage request, String trackingId, HttpStatusCode[] successfulResponseStatuses, CancellationToken cancellationToken)
   --- End of inner exception stack trace ---
   at Microsoft.Azure.NotificationHubs.ExceptionsUtility.HandleUnexpectedException(Exception ex, String trackingId)
   at Microsoft.Azure.NotificationHubs.ExceptionsUtility.TranslateToMessagingException(Exception ex, Int32 timeoutInMilliseconds, String trackingId)
   at Microsoft.Azure.NotificationHubs.NotificationHubClient.SendRequestAsync(HttpRequestMessage request, String trackingId, HttpStatusCode[] successfulResponseStatuses, CancellationToken cancellationToken)
   at Microsoft.Azure.NotificationHubs.NotificationHubClient.SendNotificationImplAsync(Notification notification, String tagExpression, String deviceHandle, CancellationToken cancellationToken)

我们像这样创建 NotificationHubClient：

new NotificationHubClient(connectionString, hubName, new NotificationHubClientSettings { OperationTimeout = TimeSpan.FromSeconds(10) });

我观察到背后的 Microsoft 实现是在每个新的 NotificationHubClient 实例化上实例化一个新的 HttpClient - 这可能是问题（众所周知的套接字耗尽），但我不知道如何解决这个问题。

有没有人遇到过同样的问题并设法以某种方式解决它？谢谢

Answer 1

最后我们通过注入解决了这个问题

    IHttpMessageHandlerFactory _httpMessageHandlerFactory;

在我们的类中并将其传递给构造函数中的 notificationHubClient：

    return new NotificationHubClient(connectionString, hubName, 
    new NotificationHubClientSettings
    {
       OperationTimeout = TimeSpan.FromSeconds(10),
       MessageHandler = _httpMessageHandlerFactory.CreateHandler()
    });

Answer 2

通知中心有一个 RESTful API。你可以看到它here。如果您想要更多控制，您可以围绕您需要的方法编写自己的包装器，确保将 HttpClient 实例设置为 Azure 函数中的静态成员变量。