feat: add Ready method to Node

[gfanton]

This PR adds a method to Node that returns a channel, which will close when the node receives its first block. The primary purpose of this is to provide a mechanism to check when the node is ready and can start handling requests.

Contributors' checklist...

• Added new tests, or not needed, or not feasible
• Provided an example (e.g. screenshot) to aid review or the PR is self-explanatory
• Updated the official documentation or not needed
• No breaking changes were made, or a BREAKING CHANGE: xxx message was included in the description
• Added references to related issues and PRs
• Provided any useful hints for running manual tests
• Added new benchmarks to generated graphs, if any. More info here.

[codecov]

Codecov Report

Attention: 15 lines in your changes are missing coverage. Please review.

Comparison is base (12b4b45) 56.13% compared to head (170506e) 56.12%.

Files	Patch %	Lines
tm2/pkg/bft/node/node.go	0.00%	14 Missing ⚠️
gno.land/pkg/integration/testing_node.go	50.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #1216      +/-   ##
==========================================
- Coverage   56.13%   56.12%   -0.02%     
==========================================
  Files         438      438              
  Lines       66151    66164      +13     
==========================================
  Hits        37134    37134              
- Misses      26126    26139      +13     
  Partials     2891     2891              

Flag	Coverage Δ
go-1.21.x	∅ <ø> (∅)
misc	∅ <ø> (∅)
misc-_test.genstd	∅ <ø> (∅)

Flags with carried forward coverage won't be shown. Click here to find out more.

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

[zivkovicmilos]

@gfanton

Please don't merge this PR yet, I'm trying to compose some thoughts on this issue

[piux2]

@gfanton Can you provide the use cases with examples why we will need this changes? I thought the integration test supposed to be conducted from outside of tendermint node service instance. Also are we trying to check first block on genesis playback or first block to be committed in consensus?

[zivkovicmilos]

Unblocking this PR, it's been in the freezer long enough

The fact that we can't rely on OnStart ending to say that the node is ready is a bit disturbing. We will tackle this in a future PR, regardless, this PR should be unblocked as it introduces a nice UX moment for tests

[zivkovicmilos]

@gfanton please resolve merge conflicts 🙏

[gfanton]

@zivkovicmilos Done! Perhaps I should rename the method to Ready() or something more explicit to better convey the purpose of this method ?

@piux2 This step is essential for the integration tests to work correctly. Currently, I am using a small external hack (see the code bellow) to ensure that the node is ready and can handle requests properly. With this new method, we provide a more intuitive way to check if the node is ready.
(Apologies for the delayed response.)

gno/gno.land/pkg/gnoland/node_inmemory.go

Lines 156 to 178 in 12b4b45

	func GetNodeReadiness(n *node.Node) <-chan struct{} {
	const listenerID = "first_block_listener"
	var once sync.Once
	nb := make(chan struct{})
	ready := func() {
	close(nb)
	n.EventSwitch().RemoveListener(listenerID)
	}
	n.EventSwitch().AddListener(listenerID, func(ev events.Event) {
	if _, ok := ev.(bft.EventNewBlock); ok {
	once.Do(ready)
	}
	})
	if n.BlockStore().Height() > 0 {
	once.Do(ready)
	}
	return nb
	}