feat: expose locally discovered node id and addresses

[ramfox]

Description

We've had multiple requests for user to get a list of nodes that have been discovered on the local network when using local-swarm-discovery. This is my attempt.

Breaking Changes

Adds locally_discovered_nodes method to Discovery trait

Adds locally_discovered_nodes method to the Endpoint

Adds rpc structs and a locally_discovered_nodes method on the client.

Notes & open questions

This may be a tragic addition to the Discovery trait, but wanted to get feedback.

Essentially, this adds a locally_discovered_nodes method to the Discovery trait, that returns None, unless your discovery mechanism discovers nodes locally.

I'm not sure how else we would expose this, without a large Discovery refactor.

Change checklist

• Self-review.
• Documentation updates following the style guide, if relevant.
• Tests if relevant.
• All breaking changes documented.

[github-actions]

Documentation for this PR has been generated and is available at: https://n0-computer.github.io/iroh/pr/2612/docs/iroh/

Last updated: 2024-08-12T01:08:18Z

[rklaehn]

Not sure if having a separate fn in Discovery is the way to go. We already have a provenance field in DiscoveryItem that is as yet mostly unused but can be used to distinguish between different discovery mechanisms.

Why not lean on that? People can just call discovery and filter out all items that don't have the right provenance. And for the address book or whatever, we should track provenance.

Maybe provenance should be an open enum instead of just a 'static str for more type safety, but that's another question.

enum Provenance {
  Local,
  Dns,
  Pkarr,
  Ticket,
   Other(&'static str),
}

or something...

[matheus23]

I'm not sure how else we would expose this, without a large Discovery refactor.

Thoughts on putting this information into Endpoint::connection_info? I.e. reusing Endpoint::add_node_addr in the LocalSwarmDiscovery task.
(See this comment)

[ramfox]

replaced by #2656