Fix Lightning Node compatibility with testnet3

[Impa10r]

Bitcoin Core now exports APP_BITCOIN_NETWORK as "testnet3", but LND still works with /home/umbrel/umbrel/app-data/lightning/data/lnd/data/chain/bitcoin/testnet folder.

For Lightning Node app to still be compatible with testnet3, it is necessary to export another variable APP_LIGHTNING_NODE_CHAIN_DIR that is equal "testnet" when APP_BITCOIN_NETWORK == "testnet3", and use it in macaroon and backup path instead of APP_BITCOIN_NETWORK:

MACAROON_DIR: "/data/.lnd/data/chain/bitcoin/${APP_LIGHTNING_NODE_CHAIN_DIR}/"
CHANNEL_BACKUP_FILE: "/data/.lnd/data/chain/bitcoin/${APP_LIGHTNING_NODE_CHAIN_DIR}/channel.backup"

[jkuchar]

testnet3 is deprecated, testnet4 should be used. ref: https://mempool.space/testnet

[Impa10r]

testnet3 is deprecated, testnet4 should be used. ref: https://mempool.space/testnet

LND and CLN do not support testnet4 yet. I use them with testnet3 to test things, it still works for my purposes.

[sharknoon]

Thank you @Impa10r for this fix :) @nmfretz @al-lac I am not an expert of lightning, but this looks reasonable to mee. But please also give me your thoughts. Thanks :)

[nmfretz]

Thanks @Impa10r. Taking a look at this now. Looks like LND v0.19.0 (currently an RC) will have testnet4 support, so we can look at adding logic to exports.sh for that when it is released.

[nmfretz]

@Impa10r I was just toying with the idea of waiting until LND 0.19.0-beta is released with testnet4 compatibility so that this problem would go away, but it looks like we're out of luck because LND's /data/chain/bitcoin/<network> directory name for testnet3 will still differ from bitcoind's network name:

https://github.com/guggero/lnd/blob/d757bb51ee992976d3b4dc625ed46d0751909069/lncfg/config.go#L108-L124

// NormalizeNetwork returns the common name of a network type used to create
// file paths. This allows differently versioned networks to use the same path.
func NormalizeNetwork(network string) string {
	// The 4th testnet isn't the "default" yet, so we'll want to explicitly
	// point that to a "testnet4" directory.
	if network == "testnet4" {
		return network
	}


	// We want to collapse "testnet3" and "testnet" to the same "testnet"
	// directory.
	if strings.HasPrefix(network, "testnet") {
		return "testnet"
	}


	return network
}

^ the code above is showing that the testnet3 dir will remain as testnet in 0.19.0-beta

That being said, I think we can actually just solve this upstream in the Bitcoin Node app very simply and it will ensure that all dependent apps work correctly. We can just export APP_BITCOIN_NETWORK as testnet instead of testnet3 and everything will just work without needing any of the changes in this PR. When 0.19.0-beta comes out with testnet4 compatibility everything should continue to work with no changes needed.

I will test and get back to you https://github.com/getumbrel/umbrel-apps/pull/2596

[nmfretz]

@Impa10r can you please test this PR https://github.com/getumbrel/umbrel-apps/pull/2596?

[Impa10r]

This PR https://github.com/getumbrel/umbrel-apps/pull/2596 solves it better, closing.