discovery: deterministic bootstrapping for local test networks by ellemouton · Pull Request #10003 · lightningnetwork/lnd

ellemouton · 2025-06-29T14:39:50Z

Follow-up from #9967
Fixes #9998

In the issue above, an itest flake appeared in the peer bootstrapping itest where a peer would not connect to 3 nodes within the itest timeout. This can happen if the ChannelGraphBootstrapper is initialised with a hashAccumulator value that would result in any of the nodes in the test node's DB being skipped on the initial or even second sampling attempt.

To fix this, we create a deterministic hash accumulator that is used in local test environments so that we can properly test the behaviour of peer bootstrapping.

coderabbitai · 2025-06-29T14:40:23Z

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yyforyongyu

LGTM🙏

discovery/bootstrapper.go

ziggie1984

LGTM 🙏

chainreg/chainregistry.go

ziggie1984 · 2025-07-01T08:50:10Z

server.go

+	// seeds.
+	if !s.cfg.Bitcoin.IsLocalNetwork() {
+		//nolint:ll
 		dnsSeeds, ok := chainreg.ChainDNSSeeds[*s.cfg.ActiveNetParams.GenesisHash]


I wonder if we update the DNSSeeds. I checked and it seems like dig ln.signet.secp.tech is down ? Not part of this PR but still wonder if you should keep those DNS seeds monitored.

probs something we should check occasionally yeah

That was my domain at some point. But a very long time ago 😅
We now have a proper seed though: https://github.com/lightningnetwork/lnd/blob/master/chainreg/chainregistry.go#L903

discovery/bootstrapper.go

docs/release-notes/release-notes-0.20.0.md

It returns true for Signet and Regtest networks.

It should be ok to use IsLocalNetwork here since the chainreg.ChainDNSSeeds map does not have an entry for either simnet or regtest.

Create an abstract hashAccumulator interface for the Channel graph bootstrapper so that we can later introduce a deterministic accumulator to be used during testing.

If LND is running on a local network, then use deterministic sampling so that we can have deterministic peer bootstrapping.

ellemouton

thanks for the reviews yall 🙏 updated

chainreg/chainregistry.go

ellemouton · 2025-07-01T09:24:36Z

server.go

+	// seeds.
+	if !s.cfg.Bitcoin.IsLocalNetwork() {
+		//nolint:ll
 		dnsSeeds, ok := chainreg.ChainDNSSeeds[*s.cfg.ActiveNetParams.GenesisHash]


probs something we should check occasionally yeah

docs/release-notes/release-notes-0.20.0.md

guggero

Very nice!

guggero · 2025-07-01T10:51:33Z

server.go

+	// seeds.
+	if !s.cfg.Bitcoin.IsLocalNetwork() {
+		//nolint:ll
 		dnsSeeds, ok := chainreg.ChainDNSSeeds[*s.cfg.ActiveNetParams.GenesisHash]


That was my domain at some point. But a very long time ago 😅
We now have a proper seed though: https://github.com/lightningnetwork/lnd/blob/master/chainreg/chainregistry.go#L903

ellemouton self-assigned this Jun 29, 2025

ellemouton added advanced Issues suitable for very experienced developers flake fix and removed advanced Issues suitable for very experienced developers labels Jun 29, 2025

ellemouton force-pushed the fixPeerBootstrappingFlake branch from aa4ed86 to 096fc03 Compare June 29, 2025 14:40

ellemouton requested review from yyforyongyu and ziggie1984 June 30, 2025 07:27

ellemouton mentioned this pull request Jun 30, 2025

graph/db: let FetchChannelEdgesByID behave as promised #10006

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yyforyongyu approved these changes Jun 30, 2025

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ellemouton force-pushed the fixPeerBootstrappingFlake branch from 096fc03 to 3f94a37 Compare June 30, 2025 11:03

This was referenced Jul 1, 2025

refactor+graph/db: refactor preparations required for incoming SQL migration code #10011

Merged

graph/db: various misc updates #10010

Merged

ziggie1984 approved these changes Jul 1, 2025

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ellemouton added 4 commits July 1, 2025 11:23

lncfg: add IsLocalNetwork helper

0456497

It returns true for Signet and Regtest networks.

server: use IsLocalNetwork check for DNS bootstrapper decision

bca6c0d

It should be ok to use IsLocalNetwork here since the chainreg.ChainDNSSeeds map does not have an entry for either simnet or regtest.

discovery: introduce hashAccumulator interface

339dd0c

Create an abstract hashAccumulator interface for the Channel graph bootstrapper so that we can later introduce a deterministic accumulator to be used during testing.

discovery: use a no-op hash accumluator for local networks

37d6390

If LND is running on a local network, then use deterministic sampling so that we can have deterministic peer bootstrapping.

ellemouton force-pushed the fixPeerBootstrappingFlake branch from 3f94a37 to 37d6390 Compare July 1, 2025 09:27

ellemouton commented Jul 1, 2025

View reviewed changes

ellemouton mentioned this pull request Jul 1, 2025

graph/db: explicitly store bitfields for channel_update message & channel flags #10007

Merged

guggero approved these changes Jul 1, 2025

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ellemouton merged commit cd7fa63 into lightningnetwork:master Jul 1, 2025
74 of 75 checks passed

ellemouton deleted the fixPeerBootstrappingFlake branch July 1, 2025 11:01

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ellemouton commented Jun 29, 2025 •

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