在 .NET Core 中使用不同的構造函數參數（DI 和非 DI）注冊多個 IHostedService 實例

Question

我有一個包含 4 個相同設備的環境，我必須連接到這些設備並通過 TCP 連接請求一些參數（每個設備都有其 IP 地址）。 我已經為需要一些參數（如 IP 地址、端口、輪詢間隔等）的單個設備實現了 class

class 實現了BackgroundService接口，並具有如下構造函數：

public RemoteDevice(RemoteDeviceConfig config, ILogger<RemoteDevice> logger)

在 class 內部有一個ExecuteAsync方法的實現，里面有一個while{}循環，它完成了所有的邏輯。

我想基於配置文件（例如，帶有設備數組的配置文件）構建一個 Worker 服務來處理 class 的多個實例

在 Program.cs 我會做：

public static void Main(string[] args)
{
    CreateHostBuilder(args).Build().Run();
}

public static IHostBuilder CreateHostBuilder(string[] args) =>
    Host.CreateDefaultBuilder(args)
        .UseSystemd()
        .ConfigureServices((hostContext, services) =>
        {
            services.AddHostedService<RemoteDevice>(); //First device
            services.AddHostedService<RemoteDevice>(); //Second device
            ...
            services.AddHostedService<RemoteDevice>(); //n-th device

        });
...
//Methods to load configuration 
...

如果沒有RemoteDeviceConfig構造函數參數，則會注入ILogger ，但如果我添加它，我不知道如何注入RemoteDeviceConfig class

我怎么了？

我將 .NET Core 3.0 與 VS2019 和 Worker Service Template 項目一起使用。

更新 - 接受的答案

我已經接受了@gldraphael answer ，並且我會添加一些有關答案評論中指定的日志記錄部分的詳細信息。

問題：在主 Worker class 中實例化的類中使用 ILogger 實現。

解決方案：在 Worker class 中注入 ILoggerFactory 並使用它為子類創建記錄器

DeviceMainClass和DeviceConfig分別是通用設備管理器及其配置。

工人.cs

List<DeviceMainClass> devices;
//Pass ILoggerFactory to worker constructor for Dependency Injection
//On worker start, instantiate all subclasses and create logger for each class
public Worker(IOptions<List<DeviceConfig>> options, ILogger<Worker> logger, ILoggerFactory loggerFactory)
{
    devices = new List<DeviceMainClass>();
    foreach(var device in _config)
    {
        devices.Add(new DeviceMainClass(_loggerFactory.CreateLogger<DeviceMainClass>(),...other parameters));
    }

    _logger = logger;
    _loggerFactory = loggerFactory;
    _config = options.Value;
}

...

protected override async Task ExecuteAsync(CancellationToken stoppingToken)
{
    while (!stoppingToken.IsCancellationRequested)
    {


        //***for testing purposes only, repeats every second***
        _logger.LogInformation("Worker running at: {time}", DateTimeOffset.Now);
        await Task.Delay(1000, stoppingToken);
    }
}

設備主類

private readonly ILogger<DeviceMainClass> _logger;

//Use
public DeviceMainClass(ILogger<DeviceMainClass> logger, ...other parameters)
{
    _logger = logger;
    ...
}

Answer 1

你想做這樣的事情：

appsettings.json

{
  "Devices": [
    { "Name": "D1" },
    { "Name": "D2" },
    { "Name": "D3" },
    { "Name": "D4" }
  ]
}

CreateHostBuilder() ：

public static IHostBuilder CreateHostBuilder(string[] args) =>
    Host.CreateDefaultBuilder(args)
        .ConfigureServices((hostContext, services) =>
        {
            services.Configure<List<DeviceConfig>>(hostContext.Configuration.GetSection("Devices"));
            services.AddHostedService<Worker>();
        });

工人：

public class Worker : BackgroundService
    {
        private readonly ILogger<Worker> _logger;
        private readonly List<DeviceConfig> config;

        public Worker(IOptions<List<DeviceConfig>> options, ILogger<Worker> logger)
        {
            config = options.Value;
            _logger = logger;
        }

        protected override async Task ExecuteAsync(CancellationToken stoppingToken)
        {
            while (!stoppingToken.IsCancellationRequested)
            {

                foreach(var device in config)
                {
                    // TODO: Process each device here
                    _logger.LogInformation("Processing device {name}", device.Name);
                }


                await Task.Delay(1000, stoppingToken);
            }
        }
    }

---

如果您當前的RemoteDevice class 有 state 信息，請在 worker 中創建List<RemoteDevice>並從配置中初始化。

Answer 2

因為我最近遇到了類似的問題 - 我遇到了這個老問題。

考慮使用任何成熟的 DI 容器，而不是默認的默認容器。 用Autofac說，它看起來像：

public class Program {
    public static void Main(string[] args) {
        Host.CreateDefaultBuilder(args)
            .UseServiceProviderFactory(new AutofacServiceProviderFactory())
            .ConfigureContainer<ContainerBuilder>(builder => { builder.RegisterType<DeviceMainClass>(); })
            .ConfigureServices(services => { services.AddHostedService<Worker>(); })
            //...
            .Build()
            .Run();
    }
}

public class DeviceConfig {
    //...
}

public class DeviceMainClass {
    private readonly ILogger<DeviceMainClass> _logger;
    private readonly DeviceConfig _deviceConfig;

    public DeviceMainClass(ILogger<DeviceMainClass> logger, DeviceConfig deviceConfig) {
        _logger = logger;
        _deviceConfig = deviceConfig;
    }
}

public class Worker : BackgroundService {
    List<DeviceMainClass> devices;

    private readonly ILogger<Worker> _logger;
    private readonly List<DeviceConfig> _config;

    public Worker(IOptions<List<DeviceConfig>> options, Func<DeviceConfig, DeviceMainClass> deviceFactory, ILogger<Worker> logger) {
        _logger = logger;
        _config = options.Value;
        devices = new List<DeviceMainClass>();
        foreach (var deviceConfig in _config) {
            //autofac automatically adds appropriate logger when calling DeviceMainClass constructor                
            devices.Add(deviceFactory(deviceConfig)); 
        }

    }
}

在此處和此處查看更多詳細信息。