You should be able to accomplish this by programmatically turning the feature on for Individual Actors until an upper limit is reached.
IMPORTANT NOTE: according to the documentation:
The individual actor gate is typically not designed for hundreds or
thousands of actors to be enabled. This is an explicit choice to make
it easier to batch load data from the adapters instead of performing
individual checks for actors over and over. If you need to enable
something for more than 20 individual people, I would recommend using
a group.
Now that we've agreed that we want to move forward with this anyways.. Let's talk about implementation.
Enabling the feature for an actor
The first thing you need to do is to ensure that the actor (probably a User) responds to flipper_id and that the flipper_id is unique for every actor. Once that is set up, you should be able to simply do enable the feature for a user when they see the banner like this:
flipper[:stats].enable_actor user
Counting actors enrolled in a feature
Now, in order to determine if we should enable the feature for a user, we need to determine how many users have been enrolled in the feature.
To do this we can query the Gate directly:
Flipper::Adapters::ActiveRecord::Gate.where(
feature_key: "stats",
key: "actors"
).count
This will return a count of the number of actors enrolled in a feature.
How do we know that works?
Well, let's take a look at the gem.
flipper[:stats].enable_actor actually calls Feature#enable_actor with the user we passed in earlier (that responds to flipper_id) being passed in as the actor.
Next, Feature#enable_actor passes the actor into Types::Actor.wrap which creates a new instance of Types::Actor which checks to make sure the actor isn't nil and that it has a flipper_id and then sets two instance variables, thing which is set to the actor, and value which is set to the flipper_id of the actor.
Now that we have an instance of Types::Actor, we pass it into Feature#enable which looks up the gate which in our case would be a Gates::Actor instance. Finally we call enable on the adaptor (which in your case is ActiveRecord).
In Adapters::ActiveRecord.enable we first look at gate.data_type which in our case, is :set. From there we do:
@gate_class.create! do |g|
g.feature_key = feature.key
g.key = gate.key
g.value = thing.value.to_s
end
Where, as mentioned earlier, thing.value is the flipper_id. Bingo! @gate_class is the active record class responsible for the gates table and the default table name is "flipper_gates".
Now we know exactly what to query to get a count of the actors enrolled in the feature!
number_of_actors_enrolled_in_stats_feature = Flipper::Adapters::ActiveRecord::Gate.where(
feature_key: "stats",
key: "actors"
).count
