I’m trying to add support for subscriptions to AshGraphql and I got a simple subscription working but now I’m a bit stuck.

So far I have added a way to add a new subscription and closed the loop by providing the needed notifications and resolver.

But so far it just works for plain subscriptions without some arguments.

e.g.

subscription {
  bucketCreated {
    id
    name
  }
}

What I’m trying to do is make it possible to add a filter argument to the subscription to allow the subscriber to select which resources he wants to be notified about.

Something like this

subscription {
  bucketCreated(filter: {name: {eq: "test}}}) {
    id
    name
  }
}

Now, I’m a bit stuck on how to configure the topics/context_ids. The problem is at the time a subscription is created, I could potentially serialize the filter and use it as the topic, but then I don’t really have a good way to notify the subscription when a change occurs because there are too many possible filters.

On the other hand, if I use a generic topic, the resolver is called for all the subscriptions. In the resolver, I could potentially check if the resource that triggered the change matches the filter and return in that case, but at that point, I haven’t found a way to stop the resolution without returning a value.

Another thing I looked at was if there was a way to see what subscriptions are currently active in the trigger and use that information to trigger the respective topics, but I also didn’t find a way to do this.

Does someone know of a way to achieve this?