如何从 .net 核心应用程序中触发 IotEdge 模块上的计算？

Question

我需要从管理后端应用程序触发 IotEdge 模块的一些计算。

在 https://docs.microsoft.com/en-us/azure/iot-edge/module-development 上显示

Currently, a module cannot receive cloud-to-device messages

所以看起来调用直接方法似乎是可行的方法。如何实现直接方法并从 .NET Core 应用程序中触发它？

Answer 1

在 IotEdge 模块的 Main 或 Init 方法中，您必须创建一个 ModuleClient 并将其连接到 MethodHandler：

AmqpTransportSettings amqpSetting = new AmqpTransportSettings(TransportType.Amqp_Tcp_Only);
ITransportSettings[] settings = { amqpSetting };

ModuleClient ioTHubModuleClient = await ModuleClient.CreateFromEnvironmentAsync(settings);
await ioTHubModuleClient.OpenAsync();

await ioTHubModuleClient.SetMethodHandlerAsync("MyDirectMethodName", MyDirectMethodHandler, null);

然后您必须将 DirectMethodHandler 添加到您的 IotEge 模块：

static async Task<MethodResponse> MyDirectMethodHandler(MethodRequest methodRequest, object userContext)
{
    Console.WriteLine($"My direct method has been called!");
    var payload = methodRequest.DataAsJson;
    Console.WriteLine($"Payload: {payload}");

    try
    {
        // perform your computation using the payload
    }
    catch (Exception e)
    {
         Console.WriteLine($"Computation failed! Error: {e.Message}");
         return new MethodResponse(Encoding.UTF8.GetBytes("{\"errormessage\": \"" + e.Message + "\"}"), 500);
    }

    Console.WriteLine($"Computation successfull.");
    return new MethodResponse(Encoding.UTF8.GetBytes("{\"status\": \"ok\"}"), 200);
}

然后您可以从您的 .Net 核心应用程序中触发直接方法，如下所示：

var iotHubConnectionString = "MyIotHubConnectionString";
var deviceId = "MyDeviceId";
var moduleId = "MyModuleId";
var methodName = "MyDirectMethodName";
var payload = "MyJsonPayloadString";

var cloudToDeviceMethod = new CloudToDeviceMethod(methodName, TimeSpan.FromSeconds(10));
cloudToDeviceMethod.SetPayloadJson(payload);

ServiceClient serviceClient = ServiceClient.CreateFromConnectionString(iotHubConnectionString);

try
{
    var methodResult = await serviceClient.InvokeDeviceMethodAsync(deviceId, moduleId, cloudToDeviceMethod);

    if(methodResult.Status == 200)
    {
        // Handle Success
    }
    else if (methodResult.Status == 500)
    {
        // Handle Failure
    }
 }
 catch (Exception e)
 {
     // Device does not exist or is offline
     Console.WriteLine(e.Message);
 }

如何从 .net 核心应用程序中触发 IotEdge 模块上的计算？

How can computation on an IotEdge module be triggered from within a .net core app?

c#

azure-iot-hub

azure-iot-edge