Correct the metrics for topic subscriptions

[AgeManning]

Some topic subscription metrics were not being registered as a safety mechanism to prevent us from recording metrics for unbounded number of topics.

The safety mechanism was too strict.

This PR increases the number of topics we store metrics for, and registers all the subnets and sync committees specifically to ensure these topics are always correctly accounted for.

[ackintosh]

I think gossipsub.register_topics_for_metrics should be called not only at the time of node startup but also when a fork occurs, to ensure the metrics remain accurate for a topic with the new fork digest. If I understand the code correctly, the appropriate place for this additional call would be around here:

lighthouse/beacon_node/network/src/service.rs

Lines 480 to 491 in ee6f667

	Some(_) = &mut self.next_fork_subscriptions => {
	if let Some((fork_name, _)) = self.beacon_chain.duration_to_next_fork() {
	let fork_version = self.beacon_chain.spec.fork_version_for_name(fork_name);
	let fork_digest = ChainSpec::compute_fork_digest(fork_version, self.beacon_chain.genesis_validators_root);
	info!(self.log, "Subscribing to new fork topics");
	self.libp2p.subscribe_new_fork_topics(fork_name, fork_digest);
	self.next_fork_subscriptions = Box::pin(None.into());
	}
	else {
	error!(self.log, "Fork subscription scheduled but no fork scheduled");
	}
	}

[AgeManning]

I think gossipsub.register_topics_for_metrics should be called not only at the time of node startup but also when a fork occurs, to ensure the metrics remain accurate for a topic with the new fork digest. If I understand the code correctly, the appropriate place for this additional call would be around here:

lighthouse/beacon_node/network/src/service.rs

Lines 480 to 491 in ee6f667

	Some(_) = &mut self.next_fork_subscriptions => {
	if let Some((fork_name, _)) = self.beacon_chain.duration_to_next_fork() {
	let fork_version = self.beacon_chain.spec.fork_version_for_name(fork_name);
	let fork_digest = ChainSpec::compute_fork_digest(fork_version, self.beacon_chain.genesis_validators_root);
	info!(self.log, "Subscribing to new fork topics");
	self.libp2p.subscribe_new_fork_topics(fork_name, fork_digest);
	self.next_fork_subscriptions = Box::pin(None.into());
	}
	else {
	error!(self.log, "Fork subscription scheduled but no fork scheduled");
	}
	}

I did consider this. I originally wanted to avoid the complexity, but now that you raise it, we probably should handle this case too. I'll update this PR. Thanks @ackintosh

[ackintosh]

Thanks for the update. Looks good to me. ✨

[pawanjay176]

@Mergifyio queue

[mergify]

queue

✅ The pull request has been merged automatically

The pull request has been merged automatically at 85c3204