Previously, when handling a sweep we assumed that if a sweep status
was completed, the parent batch was also finished. However, since the
batch confirmation status depends on three on-chain confirmations, it
is possible that a spend notifier was started for a sweep of an active
batch. The notifier would fetch the parent batch from the database, but
because we incorrectly assumed that the parent was confirmed (when it
was not), the DB call would fail with a 'no rows returned' error.
This failure would cause the sweep to fail and the sweep batcher to
stop, resulting in a permanent failure state.
MinFeeRate is minimum fee rate that must be used by a batch of
the sweep. If it is specified, confTarget is ignored.
This is useful for external source of fees.
This is needed to cover the code of SQLStore with tests.
To achieve compatibility with loopdb (SQLite), the following changes were done:
- DestAddr is filled to avoid crash in SQL layer
- Preimage is filled to avoid uniqueness checks by the DB
- the code working with batch IDs was changed to work correctly
when batch_id starts with 1 instead of 0
- SQL swap store has to have a swap with swap_hash from sweep
to satisfy foreign key constraint of the DB
Provide a wrapped store type, exposing ExecTx method with a subset
interface in the callback argument. BaseDB interfaces in instantout,
reservation and sweepbatcher use ExecTx with their subset Querier
instead of whole sqlc.Querier (*sqlc.Queries).
This is needed to make the packages more reusable, so they don't
depend on methods of *sqlc.Queries they don't use.
A Querier holds the methods of sqlc.Querier interface relevant for a package.
BaseDB has Querier + ExecTx method.
This change is needed to simplify further rework of ExecTx.
The race was detected in CI and locally when running with -race.
It happened between the following calls:
WARNING: DATA RACE
Write at 0x00c0003e6638 by goroutine 1374:
runtime.racewrite()
<autogenerated>:1 +0x1e
github.com/lightninglabs/loop/sweepbatcher.(*batch).Wait()
sweepbatcher/sweep_batch.go:463 +0x6e
github.com/lightninglabs/loop/sweepbatcher.(*Batcher).Run.func1()
sweepbatcher/sweep_batcher.go:272 +0x10e
Previous read at 0x00c0003e6638 by goroutine 1388:
runtime.raceread()
<autogenerated>:1 +0x1e
github.com/lightninglabs/loop/sweepbatcher.(*batch).monitorConfirmations()
sweepbatcher/sweep_batch.go:1144 +0x285
github.com/lightninglabs/loop/sweepbatcher.(*batch).handleSpend()
sweepbatcher/sweep_batch.go:1309 +0x10e4
github.com/lightninglabs/loop/sweepbatcher.(*batch).Run()
sweepbatcher/sweep_batch.go:526 +0xb04
github.com/lightninglabs/loop/sweepbatcher.(*Batcher).spinUpBatch.func1()
sweepbatcher/sweep_batcher.go:455 +0xbd
The race was caused because wg.Add(1) and wg.Wait() were running from different
goroutines (one goroutine was running batch.Run() and another - batcher.Run()).
To avoid this scenario, wg.Wait() call was moved into batch.Run() call, so it
waits itself for its children goroutines, after which the channel b.finished
is closed, and it serves a signal for external waiters (the batcher, calling
batch.Wait()).
Also the channel batch.stopped was renamed to batch.stopping to better reflect
its nature.
Added TestSweepBatcherCloseDuringAdding to make sure adding a sweep during
shutting down does not cause a crash. The test did not catch the original
race condition.
