无法使用 IOptionsMonitor 检测 ASP.NET 内核的变化

Question

I am working on Asp.Net Core app

I want to change the configuration settings after running the application

I am using IOptionsMonitor, but it is not detecting changes

In Startup.cs -> Configuration() method I have

services.Configure<Config>(Configuration.GetSection("someConfig"));

In a different class where these config settings are read, I wrote something like

var someConfig= serviceProvider.GetRequiredService<IOptionsMonitor<Config>>();

But when I change the configuration file (Json File), the change is not detected, and someConfig does not change.

Config POCO class:

public class Config
{
    public string name {get; set;}
    //More getters and setters
}

Edit:

services.AddSingleton<ConfigHelpers>;

I am using a singleton object in which I am trying to read the config. It works fine if its not a snigleton. Is there a way to change the config even in a singleton object?

in ConfigHelpers.cs

var someConfig= serviceProvider.GetRequiredService<IOptionsMonitor<Config>();

since it is defined as singleton in Startup.cs, changes made to Config are not reflected.

Answer 1

I am working on Asp.Net Core app

I want to change the configuration settings after running the application

I am using IOptionsMonitor, but it is not detecting changes

In Startup.cs -> Configuration() method I have

services.Configure<Config>(Configuration.GetSection("someConfig"));

In a different class where these config settings are read, I wrote something like

var someConfig= serviceProvider.GetRequiredService<IOptionsMonitor<Config>>();

But when I change the configuration file (Json File), the change is not detected, and someConfig does not change.

Config POCO class:

public class Config
{
    public string name {get; set;}
    //More getters and setters
}

Edit:

services.AddSingleton<ConfigHelpers>;

I am using a singleton object in which I am trying to read the config. It works fine if its not a snigleton. Is there a way to change the config even in a singleton object ?

in ConfigHelpers.cs

var someConfig= serviceProvider.GetRequiredService<IOptionsMonitor<Config>();

since it is defined as singleton in Startup.cs, changes made to Config are not reflected.

Answer 2

I am working on Asp.Net Core app

I want to change the configuration settings after running the application

I am using IOptionsMonitor, but it is not detecting changes

In Startup.cs -> Configuration() method I have

services.Configure<Config>(Configuration.GetSection("someConfig"));

In a different class where these config settings are read, I wrote something like

var someConfig= serviceProvider.GetRequiredService<IOptionsMonitor<Config>>();

But when I change the configuration file (Json File), the change is not detected, and someConfig does not change.

Config POCO class:

public class Config
{
    public string name {get; set;}
    //More getters and setters
}

Edit:

services.AddSingleton<ConfigHelpers>;

I am using a singleton object in which I am trying to read the config. It works fine if its not a snigleton. Is there a way to change the config even in a singleton object ?

in ConfigHelpers.cs

var someConfig= serviceProvider.GetRequiredService<IOptionsMonitor<Config>();

since it is defined as singleton in Startup.cs, changes made to Config are not reflected.

Answer 3

To detect configuration changes, a listener must be registered to the IOptionsMonitor by using its OnChange method.

Example on a BackgroundService :

// ...
using Microsoft.Extensions.Hosting;
using Microsoft.Extensions.Options;
using System.Threading;

public class MySingletonService : BackgroundService
{
    private IDisposable _optionsChangedListener;
    private MyOptions _myCurrentOptions;

    public MySingletonService(IOptionsMonitor<MyOptions> optionsMonitor)
    {
        _optionsChangedListener = optionsMonitor.OnChange(MyOptionsChanged);
        _myCurrentOptions = optionsMonitor.CurrentValue;
    }

    private void MyOptionsChanged(MyOptions newOptions, string arg2)
    {
        _myCurrentOptions = newOptions;
    }

    protected override async Task ExecuteAsync(CancellationToken stoppingToken)
    {
        while (!stoppingToken.IsCancellationRequested)
        {
            Console.WriteLine(_myCurrentOptions.MyProperty);
            await Task.Delay(1000, stoppingToken);
        }
    }

    public override void Dispose()
    {
        _optionsChangedListener.Dispose();
        base.Dispose();
    }
}

public class MyOptions
{
    public const string SectionKey = "MyOptions";

    public string MyProperty { get; set; }
}