Azure IoT Hub DPS custom allocation policies by functions- 在DPS中启用设备自定义分配策略（C#示例）

Azure IoT Hub DPS custom allocation policies by functions- 在DPS中启用设备自定义分配策略

视频介绍：

您可以在B站观看视频介绍：https://www.bilibili.com/video/BV11A411t7TB/

或在本站观看视频：

图文介绍：

本问参考官网文档：https://docs.microsoft.com/zh-cn/azure/iot-dps/how-to-use-custom-allocation-policies

在实际的业务中，可能存在某个DPS服务根据特定的策略将设备分配到不同的Azure IoT Hub 的情况，比如：

1. 大型项目中，将不同客户的设备分配到该客户独有的IoT Hub中；

2. 根据硬件版本号，将V1.1的版本号分配到中国东部2的IoT Hub，将V1.2的分配到中国北部的IoT Hub；

3. 根据硬件种类，将冰箱分配到冰箱专用的IoT Hub, 将空调分配到空调专用的IoT Hub；

4. 其他场景

这时候的这个分配规则，就是自定义规则，通过Azure functions实现，示意图如下：

本例中，

1. 创建了两个IoT Hub，一个是冰箱专用的，Hub名称包含 fridge字样，一个是空调专用的，hub名称包含conditioner字样；

2. 1个DPS服务，链接了上述两个IoT Hub, 配置了一个Function 自定义分配规则；

3. 1个function app，通过http触发，规则如上述图片所示；

4. 使用示例代码(C#)模拟设备进行测试，下载链接：https://codeload.github.com/Azure-Samples/azure-iot-samples-csharp/zip/master

重点步骤：

1.创建两个IoT Hub, 一个是冰箱专用的，Hub名称包含 fridge字样，一个是空调专用的，hub名称包含conditioner字样

2. 创建1个DPS服务

3.链接两个IoT Hub:

4. 准备Functions, Http 触发：

引用如下包：

<PackageReference Include="Microsoft.Azure.Devices.Provisioning.Service" Version="1.5.0" />  
<PackageReference Include="Microsoft.Azure.Devices.Shared" Version="1.16.0" />

代码如下：

using System;
using System.IO;
using System.Threading.Tasks;
using Microsoft.AspNetCore.Mvc;
using Microsoft.Azure.WebJobs;
using Microsoft.Azure.WebJobs.Extensions.Http;
using Microsoft.AspNetCore.Http;
using Microsoft.Extensions.Logging;
using Newtonsoft.Json;
using Microsoft.Azure.Devices.Shared;               // For TwinCollection
using Microsoft.Azure.Devices.Provisioning.Service; // For TwinState

namespace Company.Function
{
    public static class HttpTriggerCSharp1
    {
        [FunctionName("HttpTriggerCSharp1")]
        public static async Task<IActionResult> Run(
            [HttpTrigger(AuthorizationLevel.Anonymous, "get", "post", Route = null)] HttpRequest req,
            ILogger log)
        {
            log.LogInformation("C# HTTP trigger function processed a request.");

    // Get request body
    string requestBody = await new StreamReader(req.Body).ReadToEndAsync();
    dynamic data = JsonConvert.DeserializeObject(requestBody);

    log.LogInformation("Request.Body:...");
    log.LogInformation(requestBody);

    // Get registration ID of the device
    string regId = data?.deviceRuntimeContext?.registrationId;

    string message = "Uncaught error";
    bool fail = false;
    ResponseObj obj = new ResponseObj();

    if (regId == null)
    {
        message = "Registration ID not provided for the device.";
        log.LogInformation("Registration ID : NULL");
        fail = true;
    }
    else
    {
        string[] hubs = data?.linkedHubs.ToObject<string[]>();

        // Must have hubs selected on the enrollment
        if (hubs == null)
        {
            message = "No hub group defined for the enrollment.";
            log.LogInformation("linkedHubs : NULL");
            fail = true;
        }
        else
        {
            // This is a air-conditioner
            if (regId.Contains("-conditioner"))
            {
                //Find the "conditioner" IoT hub configured on the enrollment
                foreach(string hubString in hubs)
                {
                    if (hubString.Contains("-conditioner"))
                        obj.iotHubHostName = hubString;
                }

                if (obj.iotHubHostName == null)
                {
                    message = "No conditioner hub found for the enrollment.";
                    log.LogInformation(message);
                    fail = true;
                }
                else
                {
                    // Specify the initial tags for the device.
                    TwinCollection tags = new TwinCollection();
                    tags["deviceType"] = "conditioner";

                    // Specify the initial desired properties for the device.
                    TwinCollection properties = new TwinCollection();
                    properties["state"] = "code";
                    

                    // Add the initial twin state to the response.
                    TwinState twinState = new TwinState(tags, properties);
                    obj.initialTwin = twinState;
                }
            }
            // This is fridge
            else if (regId.Contains("-fridge"))
            {
                //Find the "-heatpumps-" IoT hub configured on the enrollment
                foreach(string hubString in hubs)
                {
                    if (hubString.Contains("-fridge"))
                        obj.iotHubHostName = hubString;
                }

                if (obj.iotHubHostName == null)
                {
                    message = "No fridge hub found for the enrollment.";
                    log.LogInformation(message);
                    fail = true;
                }
                else
                {
                    // Specify the initial tags for the device.
                    TwinCollection tags = new TwinCollection();
                    tags["deviceType"] = "fridge";

                    // Specify the initial desired properties for the device.
                    TwinCollection properties = new TwinCollection();
                    properties["state"] = "on";
                    properties["temperatureSetting"] = "-18";

                    // Add the initial twin state to the response.
                    TwinState twinState = new TwinState(tags, properties);
                    obj.initialTwin = twinState;
                }
            }
            // Unrecognized device.
            else
            {
                fail = true;
                message = "Unrecognized device registration.";
                log.LogInformation("Unknown device registration");
            }
        }
    }

    log.LogInformation("\nResponse");
    log.LogInformation((obj.iotHubHostName != null) ? JsonConvert.SerializeObject(obj) : message);

    return (fail)
        ? new BadRequestObjectResult(message) 
        : (ActionResult)new OkObjectResult(obj);
      }    
    }
    public class ResponseObj
        {
            public string iotHubHostName {get; set;}
            public TwinState initialTwin {get; set;}
        }
}

发布Function: