Fix some strange vsp package bugs

Unexport the Queue method, so that external callers are less likely to
abuse it.  It will panic if the queue channel has already closed.

Use returns instead of breaks when inside of a select statement and
the goal was to break out of an outer loop.  The break statement will
break out of the switch statement, not the loop.

Do not queue items from Process.  This was needlessly recursive
(Process -> queue -> Process) and caused the first Process call to
return the original error before attempting the second process
(despite waiting for 2 minutes in the foreground), by which time the
second Process call could fail due to the wallet locking after the
first Process call returned.

Remove a log of expected context cancellation errors.

internal/vsp/vsp.go

@@ -4,6 +4,7 @@ import (
 	"context"
 	"crypto/ed25519"
 	"encoding/base64"
+	"errors"
 	"fmt"
 	"net"
 	"net/http"
@@ -99,7 +100,9 @@ func New(ctx context.Context, vspURL, pubKeyStr string, purchaseAccount, changeA
 		for {
 			ntfns, err := c.Recv()
 			if err != nil {
-				log.Errorf("Recv failed: %v", err)
+				if !errors.Is(err, context.Canceled) {
+					log.Errorf("Recv failed: %v", err)
+				}
 				break
 			}
 			watch := make(map[chainhash.Hash]chainhash.Hash)
@@ -134,7 +137,7 @@ func New(ctx context.Context, vspURL, pubKeyStr string, purchaseAccount, changeA
 						log.Infof("VSP has successfully confirmed the fee tx for %v", txHash)
 					case "error":
 						log.Warnf("VSP failed to broadcast feetx for %v -- restarting process", txHash)
-						v.Queue(ctx, *txHash, nil)
+						v.queueItem(ctx, *txHash, nil)
 					default:
 						log.Warnf("VSP responded with %v for %v", ticketStatus.FeeTxStatus, txHash)
 						continue
@@ -180,7 +183,7 @@ func New(ctx context.Context, vspURL, pubKeyStr string, purchaseAccount, changeA
 		for {
 			select {
 			case <-ctx.Done():
-				break
+				return
 			case added := <-t.C:
 				v.outpointsMu.Lock()
 				for _, addedHash := range added.UnminedTransactionHashes {
@@ -214,7 +217,7 @@ func New(ctx context.Context, vspURL, pubKeyStr string, purchaseAccount, changeA
 			select {
 			case <-ctx.Done():
 				close(v.queue)
-				break
+				return
 
 			case queuedItem := <-v.queue:
 				feeTx, err := v.Process(ctx, queuedItem.TicketHash, nil)
@@ -243,7 +246,7 @@ type queueEntry struct {
 	FeeTx      *wire.MsgTx
 }
 
-func (v *VSP) Queue(ctx context.Context, ticketHash chainhash.Hash, feeTx *wire.MsgTx) {
+func (v *VSP) queueItem(ctx context.Context, ticketHash chainhash.Hash, feeTx *wire.MsgTx) {
 	queuedTicket := &queueEntry{
 		TicketHash: ticketHash,
 		FeeTx:      feeTx,
@@ -275,7 +278,7 @@ func (v *VSP) Sync(ctx context.Context) {
 				continue
 			}
 			// TODO get unpublished fee txs here and sync them
-			v.Queue(ctx, *ticketSummary.Ticket.Hash, nil)
+			v.queueItem(ctx, *ticketSummary.Ticket.Hash, nil)
 		}
 
 		return false, nil
@@ -288,12 +291,19 @@ func (v *VSP) Sync(ctx context.Context) {
 }
 
 func (v *VSP) Process(ctx context.Context, ticketHash chainhash.Hash, credits []wallet.Input) (*wire.MsgTx, error) {
-	feeAmount, err := v.GetFeeAddress(ctx, ticketHash)
-	if err != nil {
-		if strings.Contains(err.Error(), "ticket transaction could not be broadcast") {
+	var feeAmount dcrutil.Amount
+	var err error
+	for i := 0; i < 2; i++ {
+		feeAmount, err = v.GetFeeAddress(ctx, ticketHash)
+		if err == nil {
+			break
+		}
+		const broadcastMsg = "ticket transaction could not be broadcast"
+		if err != nil && i == 0 && strings.Contains(err.Error(), broadcastMsg) {
 			time.Sleep(2 * time.Minute)
-			v.Queue(ctx, ticketHash, nil)
 		}
+	}
+	if err != nil {
 		return nil, err
 	}