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Refactor to allow better Bitcoin fee estimation in the future.

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This commit is contained in:
catbref 2020-08-21 17:37:04 +01:00
parent 9393689037
commit 276c479a5f
2 changed files with 60 additions and 10 deletions
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56
src/main/java/org/qortal/controller/TradeBot.java
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@ -63,7 +63,8 @@ public class TradeBot {
private static final Logger LOGGER = LogManager.getLogger(TradeBot.class);
private static final Random RANDOM = new SecureRandom();
private static final long FEE_AMOUNT = 5000L;
private static final long P2SH_B_OUTPUT_AMOUNT = 1000L; // P2SH-B output amount needs to be higher than the dust threshold (3000 sats/kB).
private static TradeBot instance;
@ -233,7 +234,7 @@ public class TradeBot {
byte[] tradeForeignPublicKeyHash = Crypto.hash160(tradeForeignPublicKey);
byte[] receivingPublicKeyHash = Base58.decode(receivingAddress); // Actually the whole address, not just PKH
// We need to generate lockTime-A: halfway of refundTimeout from now
// We need to generate lockTime-A: add tradeTimeout to now
int lockTimeA = crossChainTradeData.tradeTimeout * 60 + (int) (NTP.getTime() / 1000L);
TradeBotData tradeBotData = new TradeBotData(tradePrivateKey, TradeBotData.State.ALICE_WAITING_FOR_P2SH_A,
@ -246,7 +247,14 @@ public class TradeBot {
// Check we have enough funds via xprv58 to fund both P2SHs to cover expectedBitcoin
String tradeForeignAddress = BTC.getInstance().pkhToAddress(tradeForeignPublicKeyHash);
long totalFundsRequired = crossChainTradeData.expectedBitcoin + FEE_AMOUNT /* P2SH-A */ + FEE_AMOUNT /* P2SH-B */;
Long estimatedFee = BTC.getInstance().estimateFee(lockTimeA * 1000L);
if (estimatedFee == null) {
LOGGER.debug(() -> String.format("Couldn't estimate Bitcoin fees?"));
return ResponseResult.BTC_NETWORK_ISSUE;
}
long totalFundsRequired = crossChainTradeData.expectedBitcoin + estimatedFee /* P2SH-A */
+ P2SH_B_OUTPUT_AMOUNT + estimatedFee /* P2SH-B */;
Transaction fundingCheckTransaction = BTC.getInstance().buildSpend(xprv58, tradeForeignAddress, totalFundsRequired);
if (fundingCheckTransaction == null)
@ -257,7 +265,7 @@ public class TradeBot {
String p2shAddress = BTC.getInstance().deriveP2shAddress(redeemScriptBytes);
// Fund P2SH-A
Transaction p2shFundingTransaction = BTC.getInstance().buildSpend(tradeBotData.getXprv58(), p2shAddress, crossChainTradeData.expectedBitcoin + FEE_AMOUNT);
Transaction p2shFundingTransaction = BTC.getInstance().buildSpend(tradeBotData.getXprv58(), p2shAddress, crossChainTradeData.expectedBitcoin + estimatedFee);
if (p2shFundingTransaction == null) {
LOGGER.warn(() -> String.format("Unable to build P2SH-A funding transaction - lack of funds?"));
return ResponseResult.BTC_BALANCE_ISSUE;
@ -539,9 +547,23 @@ public class TradeBot {
byte[] redeemScript = BTCP2SH.buildScript(aliceForeignPublicKeyHash, lockTimeA, tradeBotData.getTradeForeignPublicKeyHash(), hashOfSecretA);
String p2shAddress = BTC.getInstance().deriveP2shAddress(redeemScript);
Long estimatedFee = BTC.getInstance().estimateFee(lockTimeA * 1000L);
if (estimatedFee == null) {
LOGGER.debug(() -> String.format("Couldn't estimate Bitcoin fees?"));
// Not worth trying other MESSAGEs... give up for now
return;
}
final long minimumBalance = tradeBotData.getBitcoinAmount() + estimatedFee;
Long balance = BTC.getInstance().getBalance(p2shAddress);
if (balance == null || balance < tradeBotData.getBitcoinAmount())
if (balance == null || balance < minimumBalance) {
// P2SH-A has no, or insufficient, balance
if (balance != null && balance > 0)
LOGGER.debug(() -> String.format("P2SH-A %s balance %s lower than expected %s", p2shAddress, BTC.format(balance), BTC.format(minimumBalance)));
// There might be another MESSAGE from someone else with an actually funded P2SH-A...
continue;
}
// Good to go - send MESSAGE to AT
@ -694,7 +716,13 @@ public class TradeBot {
byte[] redeemScriptBytes = BTCP2SH.buildScript(tradeBotData.getTradeForeignPublicKeyHash(), lockTimeB, crossChainTradeData.creatorBitcoinPKH, crossChainTradeData.hashOfSecretB);
String p2shAddress = BTC.getInstance().deriveP2shAddress(redeemScriptBytes);
Transaction p2shFundingTransaction = BTC.getInstance().buildSpend(tradeBotData.getXprv58(), p2shAddress, FEE_AMOUNT);
Long estimatedFee = BTC.getInstance().estimateFee(lockTimeA * 1000L);
if (estimatedFee == null) {
LOGGER.debug(() -> String.format("Couldn't estimate Bitcoin fees?"));
return;
}
Transaction p2shFundingTransaction = BTC.getInstance().buildSpend(tradeBotData.getXprv58(), p2shAddress, P2SH_B_OUTPUT_AMOUNT + estimatedFee);
if (p2shFundingTransaction == null) {
LOGGER.warn(() -> String.format("Unable to build P2SH-B funding transaction - lack of funds?"));
return;
@ -757,16 +785,24 @@ public class TradeBot {
byte[] redeemScriptBytes = BTCP2SH.buildScript(crossChainTradeData.partnerBitcoinPKH, crossChainTradeData.lockTimeB, crossChainTradeData.creatorBitcoinPKH, crossChainTradeData.hashOfSecretB);
String p2shAddress = BTC.getInstance().deriveP2shAddress(redeemScriptBytes);
int lockTimeA = tradeBotData.getLockTimeA();
Long estimatedFee = BTC.getInstance().estimateFee(lockTimeA * 1000L);
if (estimatedFee == null) {
LOGGER.debug(() -> String.format("Couldn't estimate Bitcoin fees?"));
return;
}
final long minimumBalance = P2SH_B_OUTPUT_AMOUNT + estimatedFee;
Long balance = BTC.getInstance().getBalance(p2shAddress);
if (balance == null || balance < FEE_AMOUNT) {
if (balance == null || balance < minimumBalance) {
if (balance != null && balance > 0)
LOGGER.debug(() -> String.format("P2SH-B balance %s lower than expected %s", BTC.format(balance), BTC.format(FEE_AMOUNT)));
LOGGER.debug(() -> String.format("P2SH-B %s balance %s lower than expected %s", p2shAddress, BTC.format(balance), BTC.format(minimumBalance)));
return;
}
// Redeem P2SH-B using secret-B
Coin redeemAmount = Coin.ZERO; // The real funds are in P2SH-A
Coin redeemAmount = Coin.valueOf(P2SH_B_OUTPUT_AMOUNT); // An actual amount to avoid dust filter, remaining used as fees. The real funds are in P2SH-A.
ECKey redeemKey = ECKey.fromPrivate(tradeBotData.getTradePrivateKey());
List<TransactionOutput> fundingOutputs = BTC.getInstance().getUnspentOutputs(p2shAddress);
byte[] receivingAccountInfo = tradeBotData.getReceivingAccountInfo();
@ -976,7 +1012,7 @@ public class TradeBot {
byte[] redeemScriptBytes = BTCP2SH.buildScript(tradeBotData.getTradeForeignPublicKeyHash(), crossChainTradeData.lockTimeB, crossChainTradeData.creatorBitcoinPKH, crossChainTradeData.hashOfSecretB);
String p2shAddress = BTC.getInstance().deriveP2shAddress(redeemScriptBytes);
Coin refundAmount = Coin.ZERO;
Coin refundAmount = Coin.valueOf(P2SH_B_OUTPUT_AMOUNT); // An actual amount to avoid dust filter, remaining used as fees.
ECKey refundKey = ECKey.fromPrivate(tradeBotData.getTradePrivateKey());
List<TransactionOutput> fundingOutputs = BTC.getInstance().getUnspentOutputs(p2shAddress);

14
src/main/java/org/qortal/crosschain/BTC.java
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@ -158,6 +158,20 @@ public class BTC {
return blockTimestamps.get(5);
}
/**
* Returns estimated BTC fee, in sats per 1000bytes, optionally for historic timestamp.
*
* @param timestamp optional milliseconds since epoch
* @return sats per 1000bytes, or null if something went wrong
*/
public Long estimateFee(Long timestamp) {
// TODO: This will need to be replaced with something better in the near future!
if (timestamp != null && timestamp < 1598280000000L)
return 4000L;
return 10_000L;
}
public Long getBalance(String base58Address) {
return this.electrumX.getBalance(addressToScript(base58Address));
}