onchain fees are weird at channel close because:
- you may be missing an trimmed htlc (which went to fees)
- the balance from close may have been rounded (msats cant land on
chain)
- the close might have been a past state and you've actually
ended up with more money onchain than you had in the channel. wut
This commit accounts for all of this appropriately, with some tests.
channel_close.debit should equal onchain_fee.credit (for that txid)
plus sum(chain_event.credit [wallet/channel_acct]).
In the penalty case, channel_close.debit becomes channel_close.debit +
penalty_adj.debit, i.e.
channel-close.debit + (penalty_adj.debit) =
onchain_fee.credit
+ sum(chain_event.credit [wallet/channel_acct])
Due to the way that onchain channel closes work, there is often a delay
between when the funding output is spent and the channel is considered
'closed'.
Once *every* downstream utxo of a channel has landed on chain, we
annotate the account with the resolving blockheight.
This gives us some insight into whether or not the chain fees etc of a
channel are going to update further and allows for a natural marker to
prune data (at a later date)
Pass in an account id, get out a utxo chain of the channel open and
close (and any other related htlc txs etc).
Note that this prints all wallet deposits that occurred in any of the
tx's that touched this channel.
This is fine and expected for any tx that's not the open; when
considerig the tx open event, the wallet deposit that's present is
typically the change. If there were other channels opened in the same tx
then the change won't match up exactly...
Also note that we might have ignored/missed fees for the channel
closed's spending txid, so we attempt to update those as well.
Backfilling for missed events is a beast.
We need the total output_value, and we can figure this out if we look at
the remote amount also.
We also need to account for the pushed/leased amount, as for leased
channels this really messes with onchain fee calculations.
We copy basically the events that lightningd emits for leased channels:
an open event with the 'lease fee' (pushed?) amount credited to the side
that made the lease/push; then an in-channel event to effectively push
the pushed/leased amount over to the peer it was paid to.
We run the journal entry info after this, so the journal snapshot will
take the pushed amount into account when figuring out what the further
missed in-channel payments were (if any)
Because we update the onchain_fee table every time a new event comes in,
it's possible (and in fact happens) that we get a wallet
withdraw/deposit event and then the channel open output event.
What we'd expect in this case is that the fees for the tx were credited
to the channel's account, not the wallet. But since we got the two
in/out events first, the fees were accumulated there first.
Our existing logic will add the channel's fees correctly, but we weren't
zeroing out the wallet's balance once it'd been determined that they
were 'ineligble' so to speak, for being included in the fees that round.
We now add chain events for starting channel balances, so print these
out with chain first then channel events.
Makes it less confusing for channel lease fee events.
Prints all the events for the requested account. If no account
requested, prints out all the events. Ordered by timestamp.
Changelog-Added: bookkeeper: new command `listaccountevents`
There's two situations where we're missing info.
One is we get a 'channel_closed' event (but there's no 'channel_open')
The other is a balance_snapshot arrives with information about accounts
that doesn't match what's already on disk. (For some of these cases, we
may be missing 'channel_open' events..)
In the easy case (no channel_open missing), we just figure out what the
When we print events out, we need to know the account name. This makes
our lookup a lot easier, since we just pull it out from the database
every time we query for these.
One really rough thing about how we did onchain fees is that the records update
every time a new event comes in.
The better way to do this is to create new entries for every adjustment,
so that reconciliation between printouts isn't a misery.
We add a timestamp and `update_count` to these records, so you can
roughly order them now (and have a good idea of the last time an event
that updated an onchain_fee occurred).
When the node starts up, it records missing/updated account balances
to the 'channel' events... which is kinda fucked for wallet + external
events now that i think about it but these are all treated the same
anyway so it's fine.
This is the magic piece that lets your bookkeeping data startup ok on an
already running/established node.
clightning doesn't give us any info about onchain fees (how could it?
it only knows about utxo object levels, and doesn't keep track of
how/when those are all related)
Instead, we keep running totals of the onchain fees for utxos. This
implements the master method for accounting for them, plus includes
tests to account for channel opens (across two accounts) as well as a
htlc-tx channel close.
Missing: we don't currently emit an event from cln for `withdraw`
initiated removal of funds, so the accounting for wallet -> external
funds is a bit janky. We don't account for the fees on these
transactions since we don't have the resulting 'external' event to
register them against!
niftynei
Rusty Russell