This commit makes sure that no loop variables or other temporary
variables are accessed directly in a goroutine but are instead passed
into the goroutine through a parameter. This makes sure a copy of the
value is put on the stack and is not changed while the outside loop
continues.
In this commit, we add a new option for the existing confirmation
notification system that optionally allows the caller to specify that a
block should be included as well.
The only quirk w/ the implementation here is the neutrino backend:
usually we get filtered blocks, we so need to first fetch the block
again so we can deliver the full block to the notifier. On the notifier
end, it'll only be checking for the transactions we care about, to
sending a full block doesn't affect the correctness.
We also extend the `testBatchConfirmationNotification` test to assert
that a block is only included if the caller specifies it.
This commit was previously split into the following parts to ease
review:
- 2d746f68: replace imports
- 4008f0fd: use ecdsa.Signature
- 849e33d1: remove btcec.S256()
- b8f6ebbd: use v2 library correctly
- fa80bca9: bump go modules
With go 1.17 a change to the build flags was implemented:
https://go.googlesource.com/proposal/+/master/design/draft-gobuild.md
The formatter now automatically adds the forward-compatible build tag
format and the linter checks for them, so we need to include them in our
code.
After the error is received on the filter update errChan, update the
EndHeight if we're performing a historical scan. If a block was mined
after the call to RegisterConf/RegisterSpend but before the filter was
updated, then the block would not have the filter applied. This means
that a block containing the desired conf/spend parameters would be
undetected. Fix this by ensuring the historical scan also includes this
height, as it would previously not be included.
Moves filter handling logic for connecting blocks to the
connectFilteredBlock method. The disconnect logic now lives in
disconnectFilteredBlock. After updating the filter, drainChainUpdates
is called which will drain everything from the chainUpdates chan and
apply all updates by calling either connectFilteredBlock or
disconnectFilteredBlock. This will allow callers to update their
EndHeight if performing a historical dispatch, as blocks up to this
height may not have had the filter applied.
ConcurrentQueue has internal structures so if a filterUpdate exists
in it, the idea of draining the queue may not work reliably. The
update may exist in the ConcurrentQueue but may not be available via
ChanOut() when we're ready to drain the ConcurrentQueue. Fix this by
using a regular buffered chan, which will either have the update or
not have the update. Its size is set to 100 as our tests may generate
quite a bit of updates.
This commit adds gives BtcdNotifier access to the block cache and wraps
its GetBlock method so that the block cache's mutex map for the specific
hash is used.
Adding persistency to neutrino re-scan progress. In case the re-scan
failed in the middle or the node was restarted before the re-scan
has been completed this fix will start from the last point instead
of the beginning.
On long re-scan , such as old channels on mobile devices this is
crucial.
This commit introduces an optimization for the chain scanning
used in historical confirmations notifications.
It now uses batch request instead of requesting filters one by one.
Earlier GetCFilter could return a nil-error along with a nil-filter in
cases where we failed to fetch the filter. We would just ignore the
block causing us to miss potential crucial information.
Now that GetCFilter will return an error in cases where the fetch
failed, the filter will never be nil (even for blocks with only coinbase
transactions), and we'll instead return an error.
We also increase the number of retries for the filter from the default 2
to 5.
Since GetUtxo is a potentially long running call, we would see
RegisterSpendNtfn block in some cases, in particular on starting the
chain watcher, causing lnd to hang on startup.
This commit makes the call to GetUtxo in a go routine, letting
RegisterSpendNtfn return immediately when the notification events are
created.
In this commit, we update the build to point to the latest version of
neutrino and btcwallet. The latest version of neutrino includes a number
of bug fixes, and new features like reliably transaction broadcast. The
latest version of btcwallet contains a number of bug fixes related to
properly remove invalid transactions from its database.
In this commit, we extend the NeutrinoNotifier to support registering
scripts for spends notifications. Once the script has been detected as
spent within the chain, a spend notification will be dispatched through
the Spend channel of the SpendEvent returned upon registration.
For scripts that have been spent in the past, the rescan logic has been
modified to match on the script rather than the outpoint. A concurrent
queue for relevant transactions has been added to proxy notifications
from the underlying rescan to the txNotifier. This is needed for
scripts, as we cannot perform a historical rescan for scripts through
`GetUtxo`, like we do with outpoints.
For scripts that are unspent, a filter update is sent to the underlying
rescan to ensure that we match and dispatch on the script when
processing new blocks.
Along the way, we also address an issue where we'd miss detecting that
an outpoint/script has been spent in the future due to not receiving a
historical dispatch request from the underlying txNotifier. To fix this,
we ensure that we always request the backend to notify us of the spend
once it detects it at tip, regardless of whether a historical rescan was
detected or not.
In this commit, we extend the NeutrinoNotifier to support registering
scripts for confirmation notifications. Once the script has been
detected as confirmed within the chain, a confirmation notification will
be dispatched to through the Confirmed channel of the ConfirmationEvent
returned upon registration.
For scripts that have confirmed in the past, the `historicalConfDetails`
method has been modified to determine whether the script has been
confirmed by locating the script in an output of a confirmed
transaction.
For scripts that have yet to confirm, a filter update is sent to the
underlying rescan to ensure that we match and dispatch on the script
when processing new blocks.
Along the way, we also address an issue where we'd miss detecting that a
transaction/script has confirmed in the future due to not receiving a
historical dispatch request from the underlying txNotifier. To fix this,
we ensure that we always update our filters to detect the confirmation
at tip, regardless of whether a historical rescan was detected or not.
In this commit, we modify all existing historical rescans for
ChainNotifier backends to scan backwards rather than forwards. If we
know that a transaction has been confirmed, or outpoint spent, the it's
likely that the event has recently transpired assuming we've been
offline for a short period of time. Therefore, if we scan backwards
rather than forwards, then we can save potentially hundreds or thousands
of block fetches if the event recently happened close to the tip of the
chain.
We bound this search at the genesis block, to ensure we don't underflow
the uint32 used throughout the package in the main loop.
In this commit, we alter the different ChainNotifier implementations to
dispatch confirmation and spend notifications after blocks. We do this
to ensure the external consistency of our registered clients.
In this commit, we modify the notifier to handle filter updates
synchronously. We do this to prevent race conditions between new block
notifications and filter updates. Otherwise, it's possible for a new
block to come in that should match our filter, but doesn't due to the
filter being updated after.
We also modify their order so that the filter is updated first. We do
this so we can immediately start watching for the event at tip while the
rescan is ongoing.
In this commit, we modify the logic within RegisterSpendNtfn for the
NeutrinoNotifier to account for the recent changes made to the
TxNotifier. Since it is now able to handle spend notification
registration and dispatch, we can bypass all the current logic within
the NeutrinoNotifier and interact directly with the TxNotifier instead.
The most notable change is that now we'll only attempt a historical
rescan if the TxNotifier tells us so.
