is there an example of using SSE for yoga subscriptions with cloudflare?

[jb747]

The possibility of using SSE to implement Yoga subscriptions in a cloudflare environment is mentioned in the Cloudflare integration docs. I'm curious - is there an example of this? I gave it a quick try, but ran into a problem because Cloudflare worker requests run in separate v8 isolates and Cloudflare's worker runtime does not allow I/O between isolates i.e.

1. a grapqhl subscription request establishes an SSE connection to a yoga server running on a durable object. The resolver waits on a pubsub.subscribe(). It is a streaming connection so the request isolate persists.
2. a graphql mutation request, running in a new isolate, is handled by the same server. The resolver invokes pubsub.publish(). This causes an error when the corresponding pubsub.subscribe() tries to send an event over the SSE subscription connection since it is running in a separate request isolate.

Perhaps I'm missing something.. is there a demo?

[EmrysMyrddin]

Hi, Thank you for reaching out!
In this case, you probably need an external PubSub service. This way, you will be able to comunicate between isolates.
It is in private beta for now, but CloudFlare is working on their own distributed and Worker compliant PubSub , but any other services like this one should do the trick.

[jb747]

thanks, EM. I was able to do this by switching to a datastore which can send change events over HTTP to the Cloudflare worker.