How to programmatically create an “always enabled” FeatureDefinition?

[ShayMusachanov-dev]

I’m implementing a custom IFeatureDefinitionProvider that reads features from a database or an HTTP service instead of JSON configuration. My goal is to represent a feature that is always enabled, equivalent to this JSON:

"FeatureA": {
    "enabled": true
}

Looking at the source (ConfigurationFeatureDefinitionProvider.ParseMicrosoftSchemaFeatureDefinition), the library seems to convert such JSON into a FeatureDefinition with:

• Status = FeatureStatus.Conditional
• EnabledFor containing a single FeatureFilterConfiguration with Name = "AlwaysOn"

Example based on my understanding:

var featureEnabled = new FeatureDefinition
{
    Name = "FeatureA",
    EnabledFor = new List<FeatureFilterConfiguration>
    {
        new FeatureFilterConfiguration { Name = "AlwaysOn" }
    },
    Status = FeatureStatus.Conditional
};

My questions:

1. Is this the correct/recommended way to create a feature that is always enabled without defining any conditions?
2. Is there an official API or helper for this, so I don’t have to replicate the logic from ConfigurationFeatureDefinitionProvider?
3. Are there any docs explaining this behavior?

I want to make sure my IFeatureDefinitionProvider correctly handles “always enabled” features without relying on JSON files.

Thanks!

[jimmyca15]

1. Yes
2. No
3. It looks like this got lost somewhere along the way. It should be documented here, but it seems it was not added.

[rossgrambo]

If you're interested, here is the full logic chain:

1. A call to IsEnabledAsync("FeatureA") or any other feature eval function
2. Call is routed to the primary "EvaluateFeature"
   a. FeatureDefinition is read from the IFeatureDefinitionProvider (Your implementation)
3. IsEnabledAsync helper is called with the given FeatureDefinition
4. If there are no filters, the flag is always treated as false

[zhiyuanliang-ms]

3. It looks like this got lost somewhere along the way. It should be documented here, but it seems it was not added.

@jimmyca15 The old/classic .NET schema supports the following feature flag declaration:

{"FeatureManagement": { "Beta": true }}

I removed it from the doc.

[rossgrambo]

The .NET schema wouldn't help here though. Since the reason that works is our default IFeatureDefinitionProvider turns it into a feature flag with an "AlwaysOn" filter (same as the microsoft schema enabled: true). In this case, they're using a custom IFeatureDefinitionProvider so they are still stuck re-implementing the transformation from any flag definition to a flag with the "AlwaysOn" filter.

[jimmyca15]

3. It looks like this got lost somewhere along the way. It should be documented here, but it seems it was not added.

@jimmyca15 The old/classic .NET schema supports the following feature flag declaration:

{"FeatureManagement": { "Beta": true }}
I removed it from the doc.

The think I am mentioning that needs to be documented is how to programmatically create a FeatureDefinition that evaluates as a simple on/off switch. This is particularly needed when implementing a custom IFeatureDefinitionProvider.