Azure-webjobs-sdk: WebJobsOptionsFactory implementation ignores the "validations" parameter

Created on 18 Jun 2020 · 5Comments · Source: Azure/azure-webjobs-sdk

Because the implementation of the WebJobsOptionsFactory ignores the validation, it does not perform the intended validation.

Repro steps

public class Startup : FunctionsStartup
{
    public Startup()
    {
        var config = new ConfigurationBuilder()
            .AddEnvironmentVariables();

        Configuration = config.Build();
    }

    public IConfiguration Configuration { get; }

    public override void Configure(IFunctionsHostBuilder builder)
    {
        builder.Services.AddOptions<SampleOptions>()
               .Bind(Configuration.GetSection("Sample"))
               .ValidateDataAnnotations();
    }
}

public class SampleOptions
{
    [Required]
    public string Value { get; set; }
}

Expected behavior

I expect the validation to run.
Sample:Value key if the application settings are not set and OptionsValidationException is thrown.

Actual behavior

No validation is performed and the property values are not checked.

Known workarounds

public class Startup : FunctionsStartup
{
    public override void Configure(IFunctionsHostBuilder builder)
    {
        // Replace default implementation
        builder.Services.Replace(ServiceDescriptor.Transient(typeof(IOptionsFactory<>), typeof(OptionsFactory<>)));
    }
}