Add param to prevent overpriced ticket purchases

config.go

@@ -65,6 +65,8 @@ const (
 	// ticket buyer options
 	defaultBalanceToMaintainAbsolute = 0
 	defaultTicketbuyerLimit          = 1
+	// If max ticket price is set to 0, purchase will still be made even if ticket price is too high
+	defaultMaxTicketPrice = 0
 
 	walletDbName = "wallet.db"
 )
@@ -187,6 +189,7 @@ type ticketBuyerOptions struct {
 	BalanceToMaintainAbsolute *cfgutil.AmountFlag `long:"balancetomaintainabsolute" description:"Amount of funds to keep in wallet when purchasing tickets"`
 	Limit                     uint                `long:"limit" description:"Buy no more than specified number of tickets per block"`
 	VotingAccount             string              `long:"votingaccount" description:"Account used to derive addresses specifying voting rights"`
+	MaxTicketPrice            *cfgutil.AmountFlag `long:"maxticketprice" description:"Don't buy when the price is too high"`
 }
 
 type vspOptions struct {
@@ -382,6 +385,7 @@ func loadConfig(ctx context.Context) (*config, []string, error) {
 		TBOpts: ticketBuyerOptions{
 			BalanceToMaintainAbsolute: cfgutil.NewAmountFlag(defaultBalanceToMaintainAbsolute),
 			Limit:                     defaultTicketbuyerLimit,
+			MaxTicketPrice:            cfgutil.NewAmountFlag(defaultMaxTicketPrice),
 		},
 
 		VSPOpts: vspOptions{
@@ -573,6 +577,14 @@ func loadConfig(ctx context.Context) (*config, []string, error) {
 		return loadConfigError(err)
 	}
 
+	// Check valid Maxticketprice param
+	if cfg.TBOpts.MaxTicketPrice.ToCoin() < 0 {
+		str := "%s: maxticketprice cannot be negative: %v"
+		err := errors.Errorf(str, funcName, cfg.TBOpts.MaxTicketPrice)
+		fmt.Fprintln(os.Stderr, err)
+		return loadConfigError(err)
+	}
+
 	// Exit if you try to use a simulation wallet with a standard
 	// data directory.
 	if !cfg.AppDataDir.ExplicitlySet() && cfg.CreateTemp {

dcrwallet.go

@@ -335,6 +335,7 @@ func run(ctx context.Context) error {
 				BuyTickets:         cfg.EnableTicketBuyer,
 				Account:            purchaseAccount,
 				Maintain:           cfg.TBOpts.BalanceToMaintainAbsolute.Amount,
+				MaxTicketPrice:     cfg.TBOpts.MaxTicketPrice.Amount,
 				Limit:              int(cfg.TBOpts.Limit),
 				VotingAccount:      votingAccount,
 				Mixing:             cfg.Mixing,

sample-dcrwallet.conf

@@ -238,6 +238,7 @@
 
 ; Amount of funds to keep in wallet when stake mining
 ; ticketbuyer.balancetomaintainabsolute=0
+; ticketbuyer.maxticketprice=0
 
 [VSP Options]
 

ticketbuyer/tb.go

@@ -30,6 +30,9 @@ type Config struct {
 	// Minimum amount to maintain in purchasing account
 	Maintain dcrutil.Amount
 
+	// Maximum ticket price allowed to be purchased
+	MaxTicketPrice dcrutil.Amount
+
 	// Limit maximum number of purchased tickets per block
 	Limit int
 
@@ -282,11 +285,11 @@ func (tb *TB) buy(ctx context.Context, passphrase []byte, tip *wire.BlockHeader,
 	}
 
 	purchaseTicketReq := &wallet.PurchaseTicketsRequest{
-		Count:         buy,
-		SourceAccount: account,
-		MinConf:       minconf,
-		Expiry:        expiry,
-
+		Count:          buy,
+		SourceAccount:  account,
+		MinConf:        minconf,
+		Expiry:         expiry,
+		MaxTicketPrice: cfg.MaxTicketPrice,
 		// CSPP
 		Mixing:             mixing,
 		VotingAccount:      votingAccount,

wallet/createtx.go

@@ -1204,6 +1204,11 @@ func (w *Wallet) purchaseTickets(ctx context.Context, op errors.Op,
 		return nil, err
 	}
 
+	// If the ticket price exceeds the max ticket price, skipping purchase
+	if req.MaxTicketPrice > 0 && ticketPrice > req.MaxTicketPrice {
+		return nil, errors.E(op, errors.Invalid, "Skipping purchase: Ticket price exceeds max ticket price.")
+	}
+
 	const stakeSubmissionPkScriptSize = txsizes.P2PKHPkScriptSize + 1
 
 	// Make sure that we have enough funds. Calculate different

wallet/wallet.go

@@ -1552,6 +1552,7 @@ type PurchaseTicketsRequest struct {
 	SourceAccount    uint32
 	MinConf          int32
 	Expiry           int32
+	MaxTicketPrice   dcrutil.Amount
 	VotingAccount    uint32 // Used when Mixing == true || UseVotingAccount == true
 	UseVotingAccount bool   // Forces use of supplied voting account.
 	DontSignTx       bool