Holochain Forum

PubSub feature

So holochain has a websockets implementation in rust which is great…
However as far as I understand it is currently quite simple.
The conductor listens on a websocket port for RPC calls and responds back using the signal mechanism which broadcasts (remote or local) to all clients of a hApp listening.

But imagine you have a holochain conductor (server) hosting many hApps and you want different hApps to get custom (individual or group) signals back. Then you need a publish subscibe pattern. A way to create publish subscriber “topics” such that signals are broadcast only to their relevant client hApps. I believe this feature is in development and look forward to using it.

Currently it seems that the payload of the signal can include differentiating cellID’s so one can filter messages which are not applicable to hApp… however its a workaround and hApp developers should not have to make such filtering in the future. Any news on PubSub work? @thedavidmeister

As far as I’ve been able to gather, that feature would be relatively low on the priority list, even though I know that there is some boilerplate in the underlying code that paves the way for it.

What’s the issue with just filtering signals for relevance for now?

By the way, things I’ve gathered are ‘up’ the list are

  • release process and cycle
  • deepkey
  • sqllite integration

new wasmer is also up on the list so we can use the singlepass backend without nightly rust

pubsub will happen when the time comes :slight_smile:

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Excellent @thedavidmeister hows that coming along?

um broadly i have all the tests passing and benchmarks are looking good

bit blocked atm on a memory leak upstream in wasmer that will definitely impact us

i got about 1/3rd through pulling it into the conductor

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