In this commit, we modify our TxConfNotifier struct to allow handling
notification registrations asynchronously. The Register method has been
refactored into two: Register and UpdateConfDetails. In the case that a
transaction we registered for notifications on has already confirmed,
we'll need to determine its confirmation details on our own. Once done,
this can be provided within UpdateConfDetails.
This change will pave down the road for our different chain notifiers to
handle potentially long rescans asynchronously to prevent blocking the
caller.
In this commit, we modify the way to handle historical spend dispatches
to ensure that we don't block the client for very old rescans. Rather
than blocking and waiting for the rescan to finish (which may take
minutes in the worst case), we'll now instead launch a goroutine to
handle the async response of the rescan.
This commit increases the time we wait for a spend client to notify a
mempool spend from 50ms to 10s. This is done to catch the case where
bitcoind would use up to 7 seconds before notifying about a mempool
spend, which wasn't caught by the test.
This commit fix a bug within the bitcoind notifier logic, which would
ignore the passed mempool argument, and notify spentness whether the
spending transaction was confirmed or not. The logic used to fix this is
similar to what is already done for the btcd backend.
In this commit, we fix a recently introduced bug which can result in a
panic when bitcoind nodes without a txindex active are started. The
issue was that we would still defence the transaction's blockhash, which
would be nil if we detected that the backend didn't have the txindex
active.
Before this commit, we relied on the need of full nodes to enable the
transaction index. This allowed us to fetch historical details about
transactions in order to register and dispatch confirmation and spend
notifications.
This commit allows us to drop that requirement by providing a fallback
method to use when the transaction index is not enabled. This fallback
method relies on manually scanning blocks for the transactions
requested, starting from the earliest height the transactions could have
been included in, to the current height in the chain.
This commit extends the test to exercise a scanario that wasn't properly
covered, by registering for a confirmed spend notification for a
historical spend. We also extend the test to make sure it handles buried
spends properly.
This commit fixes a recently introduced bug in the btcdnotifier, where
we would skip all spend clients waiting for a confirmed spend in
txUpdates. The regular case where a spend is included in a new block was
correctly handled in onBlockConnected, but the txUpdates queue is also
used for confirmed spends during rescans, which we would miss. This
commit fixes that by checking if the tx update is confirmed or
unconfirmed, and acts accordingly.
In this commit, we introduce the ability for the different ChainNotifier
implements to send incremental updates to the subscribers of transaction
confirmations. These incremental updates represent how many
confirmations are left for the transaction to be confirmed. They are
sent to the subscriber at every new height of the chain.
In this commit, we avoid storing extra copies of a transaction when
multiple clients register to be notified for the same transaction. We do
this by using a set, which only stores unique elements.
In this commit, we add a new Updates channel to our ConfirmationEvent
struct. This channel will be used to deliver updates to a subscriber of
a confirmation notification. Updates will be delivered at every
incremental height of the chain with the number of confirmations
remaining for the transaction to be considered confirmed by the
subscriber.
This commit changes the chainntnfs tests to adhere to the new
RegisterSpendNtfn signature. It also makes sure that for the test
testSpendNotification, we are only getting notified when a spend is
mined, as previously btcd would notify on mempool inclusion, while
neutrino and bitcoind would notify only on confirmation, and the test
wouldn't catch this.
This commit adds a boolean to RegisterSpendNtfn, giving the caller the
option to only register for notifications on confirmed spends. This is
implemented for the btcd backend using logic similar to what is in used
for Neutrino, paving the way for later unifying them.
This commit moves the call to the bitcoind backend to start watching an
outpoint for spentness to after we have recorded the outpoint in our
list of clients. This is done to avoid a race that we saw using the btcd
backend, and it is probable that it can also happen using bitcoind.
This commit moves the call to the btcd backend to start watching an
outpoint for spentness to after we have recorded the outpoint in our
list of clients. This is done to avoid a race that could occur if btcd
quicly sent a spend notification before we had been able to record it in
our map, essentially losing it.
In this commit, we fix a lingering bug related to the way that we
deliver block epoch notifications to end users. Before this commit, we
would launch a new goroutine for *each block*. This was done in order
to ensure that the notification dispatch wouldn’t block the main
goroutine that was dispatching the notifications. This method archived
the goal, but had a nasty side effect that the goroutines could be
re-ordered during scheduling, meaning that in the case of fast
successive blocks, then notifications would be delivered out of order.
Receiving out of order notifications is either disallowed, or can cause
sub-systems that rely on these notifications to get into weird states.
In order to fix this issue, we’ll no longer launch a new goroutine to
deliver each notification to an awaiting client. Instead, each client
will now gain a concurrent in-order queue for notification delivery.
Due to the internal design of chainntnfs.ConcurrentQueue, the caller
should never block, yet the receivers will receive notifications in
order. This change solves the re-ordering issue and also minimizes the
number of goroutines that we’ll create in order to deliver block epoch
notifications.
In this commit, we fix an issue that was recently introduced to the way
we handle historical dispatches for the neutrino notifier. In a recent
change, we no return an error if we’re unable to actually find the
transaction that spends an outpoint. If this is the case, then the
outpoint is actually unspent, and we should proceed as normal.
In this commit, we fix a race condition related to the way we attempt
to query to see if an outpoint has already been spent by the time it’s
registered within the ChainNotifier. If the transaction creating the
outpoint hasn’t made it into the mempool by the time we execute the
GetTxOut call, then we’ll attempt to query for the transaction itself.
In this case, if we query for the transaction, then the block hash
field will be empty as it hasn’t yet made it into a block. Under the
previous logic, we’d then attempt to force a rescan. This is an issue
as the forced rescan will fail since it’ll try to fetch the block hash
of all zeroes.
In this commit, we fix this issue by only entering this “fallback to
rescan” logic iff, the transaction has actually been mined.
