print a few logs to debug fees and make sure gasPrice get increased a…

…t least by 1 sat per byte

zetaclient/btc_signer.go

@@ -274,7 +274,7 @@ func (signer *BTCSigner) TryProcessOutTx(send *types.CrossChainTx, outTxMan *Out
 
 	sizelimit := params.OutboundTxGasLimit
 	gasprice, ok := new(big.Int).SetString(params.OutboundTxGasPrice, 10)
-	if !ok || gasprice.Cmp(big.NewInt(0)) < 0 {
+	if !ok || gasprice.Cmp(big.NewInt(0)) <= 0 {
 		logger.Error().Msgf("cannot convert gas price  %s ", params.OutboundTxGasPrice)
 		return
 	}
@@ -295,9 +295,15 @@ func (signer *BTCSigner) TryProcessOutTx(send *types.CrossChainTx, outTxMan *Out
 	networkInfo, err := signer.rpcClient.GetNetworkInfo()
 	if err != nil {
 		logger.Error().Err(err).Msgf("cannot get bitcoin network info")
+	} else {
+		satPerByte := feeRateToSatPerByte(networkInfo.RelayFee)
+		if satPerByte.Cmp(big.NewInt(0)) == 0 {
+			logger.Info().Msgf("relayFee is less than 1 sat/byte; use 1 sat/byte")
+			satPerByte = big.NewInt(1)
+		}
+		logger.Info().Msgf("increase gasprice %s by %s, relayFee %f", gasprice.String(), satPerByte.String(), networkInfo.RelayFee)
+		gasprice.Add(gasprice, satPerByte)
 	}
-	satPerByte := feeRateToSatPerByte(networkInfo.RelayFee)
-	gasprice.Add(gasprice, satPerByte)
 
 	logger.Info().Msgf("SignWithdrawTx: to %s, value %d sats", addr.EncodeAddress(), params.Amount.Uint64())
 	logger.Info().Msgf("using utxos: %v", btcClient.utxos)