Beat [3/4]: prepare resolvers to handle the blockbeat

contractcourt/anchor_resolver.go

@@ -2,6 +2,7 @@ package contractcourt
 
 import (
 	"errors"
+	"fmt"
 	"io"
 	"sync"
 
@@ -23,9 +24,6 @@ type anchorResolver struct {
 	// anchor is the outpoint on the commitment transaction.
 	anchor wire.OutPoint
 
-	// resolved reflects if the contract has been fully resolved or not.
-	resolved bool
-
 	// broadcastHeight is the height that the original contract was
 	// broadcast to the main-chain at. We'll use this value to bound any
 	// historical queries to the chain for spends/confirmations.
@@ -71,7 +69,7 @@ func newAnchorResolver(anchorSignDescriptor input.SignDescriptor,
 		currentReport:        report,
 	}
 
-	r.initLogger(r)
+	r.initLogger(fmt.Sprintf("%T(%v)", r, r.anchor))
 
 	return r
 }
@@ -83,49 +81,12 @@ func (c *anchorResolver) ResolverKey() []byte {
 	return nil
 }
 
-// Resolve offers the anchor output to the sweeper and waits for it to be swept.
+// Resolve waits for the output to be swept.
 func (c *anchorResolver) Resolve() (ContractResolver, error) {
-	// Attempt to update the sweep parameters to the post-confirmation
-	// situation. We don't want to force sweep anymore, because the anchor
-	// lost its special purpose to get the commitment confirmed. It is just
-	// an output that we want to sweep only if it is economical to do so.
-	//
-	// An exclusive group is not necessary anymore, because we know that
-	// this is the only anchor that can be swept.
-	//
-	// We also clear the parent tx information for cpfp, because the
-	// commitment tx is confirmed.
-	//
-	// After a restart or when the remote force closes, the sweeper is not
-	// yet aware of the anchor. In that case, it will be added as new input
-	// to the sweeper.
-	witnessType := input.CommitmentAnchor
-
-	// For taproot channels, we need to use the proper witness type.
-	if c.chanType.IsTaproot() {
-		witnessType = input.TaprootAnchorSweepSpend
-	}
-
-	anchorInput := input.MakeBaseInput(
-		&c.anchor, witnessType, &c.anchorSignDescriptor,
-		c.broadcastHeight, nil,
-	)
-
-	resultChan, err := c.Sweeper.SweepInput(
-		&anchorInput,
-		sweep.Params{
-			// For normal anchor sweeping, the budget is 330 sats.
-			Budget: btcutil.Amount(
-				anchorInput.SignDesc().Output.Value,
-			),
-
-			// There's no rush to sweep the anchor, so we use a nil
-			// deadline here.
-			DeadlineHeight: fn.None[int32](),
-		},
-	)
-	if err != nil {
-		return nil, err
+	// If we're already resolved, then we can exit early.
+	if c.IsResolved() {
+		c.log.Errorf("already resolved")
+		return nil, nil
 	}
 
 	var (
@@ -134,7 +95,7 @@ func (c *anchorResolver) Resolve() (ContractResolver, error) {
 	)
 
 	select {
-	case sweepRes := <-resultChan:
+	case sweepRes := <-c.sweepResultChan:
 		switch sweepRes.Err {
 		// Anchor was swept successfully.
 		case nil:
@@ -160,6 +121,8 @@ func (c *anchorResolver) Resolve() (ContractResolver, error) {
 		return nil, errResolverShuttingDown
 	}
 
+	c.log.Infof("resolved in tx %v", spendTx)
+
 	// Update report to reflect that funds are no longer in limbo.
 	c.reportLock.Lock()
 	if outcome == channeldb.ResolverOutcomeClaimed {
@@ -171,7 +134,7 @@ func (c *anchorResolver) Resolve() (ContractResolver, error) {
 	)
 	c.reportLock.Unlock()
 
-	c.resolved = true
+	c.resolved.Store(true)
 	return nil, c.PutResolverReport(nil, report)
 }
 
@@ -180,15 +143,10 @@ func (c *anchorResolver) Resolve() (ContractResolver, error) {
 //
 // NOTE: Part of the ContractResolver interface.
 func (c *anchorResolver) Stop() {
-	close(c.quit)
-}
+	c.log.Debugf("stopping...")
+	defer c.log.Debugf("stopped")
 
-// IsResolved returns true if the stored state in the resolve is fully
-// resolved. In this case the target output can be forgotten.
-//
-// NOTE: Part of the ContractResolver interface.
-func (c *anchorResolver) IsResolved() bool {
-	return c.resolved
+	close(c.quit)
 }
 
 // SupplementState allows the user of a ContractResolver to supplement it with
@@ -215,3 +173,68 @@ func (c *anchorResolver) Encode(w io.Writer) error {
 // A compile time assertion to ensure anchorResolver meets the
 // ContractResolver interface.
 var _ ContractResolver = (*anchorResolver)(nil)
+
+// Launch offers the anchor output to the sweeper.
+func (c *anchorResolver) Launch() error {
+	if c.launched.Load() {
+		c.log.Tracef("already launched")
+		return nil
+	}
+
+	c.log.Debugf("launching resolver...")
+	c.launched.Store(true)
+
+	// If we're already resolved, then we can exit early.
+	if c.IsResolved() {
+		c.log.Errorf("already resolved")
+		return nil
+	}
+
+	// Attempt to update the sweep parameters to the post-confirmation
+	// situation. We don't want to force sweep anymore, because the anchor
+	// lost its special purpose to get the commitment confirmed. It is just
+	// an output that we want to sweep only if it is economical to do so.
+	//
+	// An exclusive group is not necessary anymore, because we know that
+	// this is the only anchor that can be swept.
+	//
+	// We also clear the parent tx information for cpfp, because the
+	// commitment tx is confirmed.
+	//
+	// After a restart or when the remote force closes, the sweeper is not
+	// yet aware of the anchor. In that case, it will be added as new input
+	// to the sweeper.
+	witnessType := input.CommitmentAnchor
+
+	// For taproot channels, we need to use the proper witness type.
+	if c.chanType.IsTaproot() {
+		witnessType = input.TaprootAnchorSweepSpend
+	}
+
+	anchorInput := input.MakeBaseInput(
+		&c.anchor, witnessType, &c.anchorSignDescriptor,
+		c.broadcastHeight, nil,
+	)
+
+	resultChan, err := c.Sweeper.SweepInput(
+		&anchorInput,
+		sweep.Params{
+			// For normal anchor sweeping, the budget is 330 sats.
+			Budget: btcutil.Amount(
+				anchorInput.SignDesc().Output.Value,
+			),
+
+			// There's no rush to sweep the anchor, so we use a nil
+			// deadline here.
+			DeadlineHeight: fn.None[int32](),
+		},
+	)
+
+	if err != nil {
+		return err
+	}
+
+	c.sweepResultChan = resultChan
+
+	return nil
+}

contractcourt/breach_resolver.go

@@ -2,6 +2,7 @@ package contractcourt
 
 import (
 	"encoding/binary"
+	"fmt"
 	"io"
 
 	"github.com/lightningnetwork/lnd/channeldb"
@@ -11,9 +12,6 @@ import (
 // future, this will likely take over the duties the current BreachArbitrator
 // has.
 type breachResolver struct {
-	// resolved reflects if the contract has been fully resolved or not.
-	resolved bool
-
 	// subscribed denotes whether or not the breach resolver has subscribed
 	// to the BreachArbitrator for breach resolution.
 	subscribed bool
@@ -32,7 +30,7 @@ func newBreachResolver(resCfg ResolverConfig) *breachResolver {
 		replyChan:           make(chan struct{}),
 	}
 
-	r.initLogger(r)
+	r.initLogger(fmt.Sprintf("%T(%v)", r, r.ChanPoint))
 
 	return r
 }
@@ -59,7 +57,7 @@ func (b *breachResolver) Resolve() (ContractResolver, error) {
 		// If the breach resolution process is already complete, then
 		// we can cleanup and checkpoint the resolved state.
 		if complete {
-			b.resolved = true
+			b.resolved.Store(true)
 			return nil, b.Checkpoint(b)
 		}
 
@@ -72,7 +70,7 @@ func (b *breachResolver) Resolve() (ContractResolver, error) {
 		// The replyChan has been closed, signalling that the breach
 		// has been fully resolved. Checkpoint the resolved state and
 		// exit.
-		b.resolved = true
+		b.resolved.Store(true)
 		return nil, b.Checkpoint(b)
 	case <-b.quit:
 	}
@@ -82,13 +80,14 @@ func (b *breachResolver) Resolve() (ContractResolver, error) {
 
 // Stop signals the breachResolver to stop.
 func (b *breachResolver) Stop() {
+	b.log.Debugf("stopping...")
 	close(b.quit)
 }
 
 // IsResolved returns true if the breachResolver is fully resolved and cleanup
 // can occur.
 func (b *breachResolver) IsResolved() bool {
-	return b.resolved
+	return b.resolved.Load()
 }
 
 // SupplementState adds additional state to the breachResolver.
@@ -97,7 +96,7 @@ func (b *breachResolver) SupplementState(_ *channeldb.OpenChannel) {
 
 // Encode encodes the breachResolver to the passed writer.
 func (b *breachResolver) Encode(w io.Writer) error {
-	return binary.Write(w, endian, b.resolved)
+	return binary.Write(w, endian, b.resolved.Load())
 }
 
 // newBreachResolverFromReader attempts to decode an encoded breachResolver
@@ -110,15 +109,30 @@ func newBreachResolverFromReader(r io.Reader, resCfg ResolverConfig) (
 		replyChan:           make(chan struct{}),
 	}
 
-	if err := binary.Read(r, endian, &b.resolved); err != nil {
+	var resolved bool
+	if err := binary.Read(r, endian, &resolved); err != nil {
 		return nil, err
 	}
+	b.resolved.Store(resolved)
 
-	b.initLogger(b)
+	b.initLogger(fmt.Sprintf("%T(%v)", b, b.ChanPoint))
 
 	return b, nil
 }
 
 // A compile time assertion to ensure breachResolver meets the ContractResolver
 // interface.
 var _ ContractResolver = (*breachResolver)(nil)
+
+// TODO(yy): implement it once the outputs are offered to the sweeper.
+func (b *breachResolver) Launch() error {
+	if b.launched.Load() {
+		b.log.Tracef("already launched")
+		return nil
+	}
+
+	b.log.Debugf("launching resolver...")
+	b.launched.Store(true)
+
+	return nil
+}