Question

我想使用Azure App Service从Azure IoT中心获取数据。

我尝试在Application_Start（）函数中向IoT中心注册回调事件。

当我可以在PC上使用Visual Studio 2017运行程序时，通常由Azure IoT中心触发事件并获取数据。

不幸的是，当我部署到作为“ Azure App Service”服务的Azure云时，当App Service在几秒钟内启动时，它只能从Azure IoT中心获取触发事件。

没有数据从Azure IoT中心获取，并且该事件不再触发。

我不知道原因。任何建议都将适用。

这是事件触发代码将在App Service的开头运行。入口点是Main（）函数。



    using Microsoft.ServiceBus.Messaging;
    using System;
    using System.Collections.Generic;
    using System.Configuration;
    using System.Linq;
    using System.Threading.Tasks;
    using System.Web;
    using TelemetryEPHostConsoleApp;

    namespace MCM100_Dashboard.App_Start.TelemetryProcessor
    {
        public class TelemetryMain
        {
            private const string STORAGEACCOUNT_PROTOCOL = "https";// We use HTTPS to access the storage account

            public async static void Main()
            {
                var mainTask = new Task(GetAzureData);
                mainTask.Start();
                await mainTask;
            }
            public static string GetAzureData()
            {
               // IoT Hub
                string iotHubConnectionString = ConfigurationManager.AppSettings["IoTHub.ConnectionString"];
                string eventHubPath = "messages/events";// It's hard-coded for IoT Hub
                string consumerGroupName = "mcmpush";// It's hard-coded for this workshop

                // Storage Account
                string storageAccountName = ConfigurationManager.AppSettings["StorageAccount.Name"];
                string storageAccountKey = ConfigurationManager.AppSettings["StorageAccount.Key"];
                string storageAccountConnectionString = CombineConnectionString(storageAccountName, storageAccountKey);
                string eventProcessorHostName = "eventprocessorhost";
                string leaseName = eventProcessorHostName;

                EventProcessorHost eventProcessorHost = new EventProcessorHost(
                    eventProcessorHostName,
                    eventHubPath,
                    consumerGroupName,
                    iotHubConnectionString,
                    storageAccountConnectionString,
                    leaseName);


                var options = new EventProcessorOptions
                {
                    InitialOffsetProvider = (partitionId) => DateTime.UtcNow
                };
                options.ExceptionReceived += (sender, e) => { Console.WriteLine(e.Exception); };
                re: try
                {
                    eventProcessorHost.RegisterEventProcessorAsync(options).Wait();
                }
                catch (Exception e)
                {
                    System.Threading.Thread.Sleep(1000);
                    goto re;
                }


                eventProcessorHost.UnregisterEventProcessorAsync().Wait();

                return "";

            }

            private static string CombineConnectionString(string storageAccountName, string storageAccountKey)
            {
                return "DefaultEndpointsProtocol=" + STORAGEACCOUNT_PROTOCOL + ";" +
                    "AccountName=" + storageAccountName + ";" +
                    "AccountKey=" + storageAccountKey;
            }
        }
    }



    using Microsoft.ServiceBus.Messaging;
    using System;
    using System.Collections.Generic;
    using System.Diagnostics;
    using System.Linq;
    using System.Text;
    using System.Threading.Tasks;
    using System.Net;
    using System.Configuration;
    using System.IO;
    using System.Web;

    namespace TelemetryEPHostConsoleApp
    {
        class TelemetryEventProcessor :IEventProcessor
        {
            static WebServerConnector _webSC = new WebServerConnector();

            async Task IEventProcessor.CloseAsync(PartitionContext context, CloseReason reason)
            {
                if (reason == CloseReason.Shutdown)
                {
                    await context.CheckpointAsync();
                }
            }

            Task IEventProcessor.OpenAsync(PartitionContext context)
            {
                return Task.FromResult(null);
            }

            async Task IEventProcessor.ProcessEventsAsync(PartitionContext context, IEnumerable messages)
            {
                // hope to trigger event
                foreach (EventData eventData in messages)
                {
                    string data = Encoding.UTF8.GetString(eventData.GetBytes());

                }

                //Call checkpoint every 5 minutes, so that worker can resume processing from 5 minutes back if it restarts.
                if (this.checkpointStopWatch.Elapsed > TimeSpan.FromMinutes(5))
                {
                    await context.CheckpointAsync();
                    this.checkpointStopWatch.Restart();
                }
            }

            private void ProcessMessage(string data)
            {
               return "";
            }

        }
    }

Answer 1

在RegisterEventProcessorAsync之后立即执行UnregisterEventProcessorAsync。这是为什么？您没有太多时间来处理事件。使用连续运行的Web作业从IoT中心读取数据可能会更好。

仅当您想停止监听传入事件时才应呼叫UnregisterEventProcessorAsync。注册事件处理器之后且注销之前，运行时将调用Task IEventProcessor.ProcessEventsAsync(PartitionContext context, IEnumerable messages)任意次。

还有，我见过几次return "";了吗？

Azure应用服务无法从Azure IoT中心获取数据

1 个答案: