Ability to query Kademlia peers via behaviour API

[nazar-pc]

Description

Right now there are methods for adding and removing addresses, but no direct API to query addresses. There is get_closest_local_peers that returns PeerIds, but not corresponding addresses. There is find_closest, but it is private.

Motivation

I need to be able to implement a mechanism similar to Kademlia's iterative lookups, but outside Kademlia. get_closest_local_peers is exactly what I need there, except I also need peer addresses to in order to respond to a query.

Requirements

1. get_closest_local_peers to return something like KadPeer at the minimum
2. Ability to query addresses more directly would probably be nice as well
3. Possibly making find_closest public as it seems to be doing the same thing as get_closest_local_peers except it also contains addresses and filters out source peer, which is exactly what I need

Open questions

Not sure what would be the desired API here yet, hence provided a few potential options

Are you planning to do it yourself in a pull request ?

Maybe

[dariusc93]

Hey! It sounds like you might be looking for Behaviour::get_closest_peers, no?

rust-libp2p/protocols/kad/src/behaviour.rs

Lines 730 to 739 in 93ad28c

	/// Initiates an iterative query for the closest peers to the given key.
	///
	/// The result of the query is delivered in a
	/// [`Event::OutboundQueryProgressed{QueryResult::GetClosestPeers}`].
	pub fn get_closest_peers<K>(&mut self, key: K) -> QueryId
	where
	K: Into<kbucket::Key<K>> + Into<Vec<u8>> + Clone,
	{
	self.get_closest_peers_inner(key, None)
	}

[nazar-pc]

No, I specifically want to query local Kademlia view, not doing iterative network lookups. I'll be doing network lookups on a different level in a slightly different way.

[guillaumemichel]

Yes, it makes sense that the addresses stored in the kbuckets are accessible through an API 👍🏻