[FEATURE] Options do not follow .Net standard pattern

[TibbsTerry]

Problem

Configuration of options do not follow the standard .Net options pattern
Options cannot be set via configuration and have to be 'hard-coded'

services.AddFusionCache()
    .WithOptions(o =>
    {
        // Can not access other dependencies eg IConfiguration here!
        o.DefaultEntryOptions.Duration = duration;
    });

[Test]
public void Test_WithOptions()
{
    var duration = TimeSpan.FromMinutes(50);
    var services = new ServiceCollection();
    services.AddFusionCache()
        .WithOptions(o => o.DefaultEntryOptions.Duration = duration);
    var serviceProvider = services.BuildServiceProvider();
    var fusionCache = serviceProvider.GetRequiredService<IFusionCache>();
    Assert.AreEqual(duration, fusionCache.DefaultEntryOptions.Duration);  // PASS
}

[Test]
public void Test_WithConfiguration()
{
    var duration = TimeSpan.FromMinutes(50);
    var configuration = new ConfigurationBuilder()
        .AddInMemoryCollection(new Dictionary<string, string?>  { { "DefaultDurationMinutes", duration.TotalMinutes.ToString()} })
        .Build();
    var services = new ServiceCollection();
    services.AddSingleton<IConfiguration>(configuration);
    services.AddFusionCache();
    services.AddOptions<FusionCacheOptions>()
        .Configure<IConfiguration>((options, config) =>
        {
            var durationMinutes = long.Parse(config["DefaultDurationMinutes"]!);
            options.DefaultEntryOptions.Duration = TimeSpan.FromMinutes(durationMinutes);
        });
    var serviceProvider = services.BuildServiceProvider();
    var fusionCache = serviceProvider.GetRequiredService<IFusionCache>();
    Assert.AreEqual(duration, fusionCache.DefaultEntryOptions.Duration); // FAIL
}

Solution

Confguration/Options should follow standards for .NET
ie should use
Microsoft.Extensions.DependencyInjection.OptionsServiceCollectionExtensions.Configure

Microsoft.Extensions.DependencyInjection.MemoryCacheServiceCollectionExtensions.AddDistributedMemoryCache
https://github.com/dotnet/runtime/blob/a5af0ab77caa5ed7a6844fc5f4f459e5edfe23d3/src/libraries/Microsoft.Extensions.Caching.Memory/src/MemoryCacheServiceCollectionExtensions.cs#L93
is probably a good example of how to do it.

or (less preferable solution)
change FusionCacheBuilder.SetupOptionsAction
to
Action<IServiceProvider, FusionCacheOptions>? SetupOptionsAction { get; set; }

[TibbsTerry]

Also add IValidateOptions<FusionCacheOptions>

[jodydonetti]

Hi @TibbsTerry , I tried reproducing your test locally, here it is:

[Fact]
public void _AAA()
{
var duration = TimeSpan.FromMinutes(50);
var configuration = new ConfigurationBuilder()
	.AddInMemoryCollection(new Dictionary<string, string?> { { "DefaultDurationMinutes", duration.TotalMinutes.ToString() } })
	.Build();
var services = new ServiceCollection();
services.AddSingleton<IConfiguration>(configuration);
services.AddFusionCache();
services.AddOptions<FusionCacheOptions>()
	.Configure<IConfiguration>((options, config) =>
	{
		var durationMinutes = long.Parse(config["DefaultDurationMinutes"]!);
		options.DefaultEntryOptions.Duration = TimeSpan.FromMinutes(durationMinutes);
	});
var serviceProvider = services.BuildServiceProvider();
var fusionCache = serviceProvider.GetRequiredService<IFusionCache>();
Assert.Equal(duration, fusionCache.DefaultEntryOptions.Duration); // SUCCESS
}

I did not change anything, except for adapting it to use xUnit:

• [Fact] instead of [Test]
• Assert.Equal() instead of Assert.AreEqual()

that's all, and here is the result:

Can you give me more info?

Thanks.

[TibbsTerry]

@jodydonetti
it works with
Version="2.0.0-preview-4"
but not
Version="1.4.1"

[jodydonetti]

Ah, I think I know why that is!
It's a consequence of this, which is now solved.

Can you add more details about the options validation?

Thanks!

[TibbsTerry]

https://learn.microsoft.com/en-us/aspnet/core/fundamentals/configuration/options?view=aspnetcore-9.0#options-validation
in particular
https://learn.microsoft.com/en-us/aspnet/core/fundamentals/configuration/options?view=aspnetcore-9.0#ivalidateoptionstoptions-and-ivalidatableobject

How OptionsFactory builds the options:
https://github.com/dotnet/runtime/blob/9d5a6a9aa463d6d10b0b0ba6d5982cc82f363dc3/src/libraries/Microsoft.Extensions.Options/src/OptionsFactory.cs#L55
Calling IConfigureOptions.Configure or IConfigureNamedOptions.Configure, and then IValidateOptions.Validate

[jodydonetti]

Hi @TibbsTerry thanks for the links, I'll try to see what I can do for v2.

[jodydonetti]

Hi @TibbsTerry , getting back to this.

I read the docs, and made some tests with the v2 preview.

I created this:

public class MyOptionsValidation
  : IValidateOptions<FusionCacheOptions>
{
  public ValidateOptionsResult Validate(string name, FusionCacheOptions options)
  {
    if (name == "Foo" && options.CacheName == "/")
      return ValidateOptionsResult.Fail("Oh no!");

    return ValidateOptionsResult.Success;
  }
}

Then this:

var builder = Host.CreateDefaultBuilder();
builder.ConfigureServices(services =>
{
  services
    .AddOptions<FusionCacheOptions>("Foo")
    .Configure(options =>
    {
      options.CacheName = "/";
    })
    .ValidateOnStart();

  services.AddSingleton<IValidateOptions<FusionCacheOptions>, MyOptionsValidation>();
});

var app = builder.Build();
app.Run();

This was the result:

It seems to me that v2 is aligned with all the standard patterns, so I'll close this when v2 will be released.

If you find anything else please let me know.

Thanks!

[jodydonetti]

Hi all, I still can't believe it but v2.0.0 is finally out 🎉
Now I can rest.

[TibbsTerry]

@jodydonetti I'm not too sure that you followed what I meant. Fusion cache should have its own built in Validator (that implements IValidateOptions<FusionCacheOptions> like above). This will stop users doing stupid things (like configuring negative values for timespans or other options). If its done in the correct pattern users can write their own to add to or override the existing validation.

[jodydonetti]

Hi @TibbsTerry , thanks for the clarification.
In general the options are already self validating, but I see your point: I'll try to come up with some cases where an explicit validator can make sense and proceed with the implementation.
Will update you asap.