xmr-btc-swap/swap/src/bitcoin/wallet.rs

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use crate::bitcoin::timelocks::BlockHeight;
use crate::bitcoin::{Address, Amount, Transaction};
use crate::execution_params::ExecutionParams;
use ::bitcoin::util::psbt::PartiallySignedTransaction;
use ::bitcoin::Txid;
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use anyhow::{anyhow, bail, Context, Result};
use backoff::backoff::Constant as ConstantBackoff;
use backoff::future::retry;
use bdk::blockchain::{noop_progress, Blockchain, ElectrumBlockchain};
use bdk::descriptor::Segwitv0;
use bdk::electrum_client::{self, Client, ElectrumApi};
use bdk::keys::DerivableKey;
use bdk::{FeeRate, KeychainKind};
use bitcoin::Script;
use reqwest::{Method, Url};
use serde::{Deserialize, Serialize};
use std::path::Path;
use std::sync::Arc;
use std::time::Duration;
use tokio::sync::Mutex;
use tokio::time::interval;
const SLED_TREE_NAME: &str = "default_tree";
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#[derive(Debug, thiserror::Error)]
enum Error {
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#[error("Sending the request failed")]
Io(reqwest::Error),
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#[error("Conversion to Integer failed")]
Parse(std::num::ParseIntError),
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#[error("The transaction is not minded yet")]
NotYetMined,
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#[error("Deserialization failed")]
JsonDeserialization(reqwest::Error),
#[error("Electrum client error")]
ElectrumClient(electrum_client::Error),
}
pub struct Wallet {
inner: Arc<Mutex<bdk::Wallet<ElectrumBlockchain, bdk::sled::Tree>>>,
http_url: Url,
rpc_url: Url,
}
impl Wallet {
pub async fn new(
electrum_rpc_url: Url,
electrum_http_url: Url,
network: bitcoin::Network,
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wallet_dir: &Path,
key: impl DerivableKey<Segwitv0> + Clone,
) -> Result<Self> {
// Workaround for https://github.com/bitcoindevkit/rust-electrum-client/issues/47.
let config = electrum_client::ConfigBuilder::default().retry(2).build();
let client = Client::from_config(electrum_rpc_url.as_str(), config)
.map_err(|e| anyhow!("Failed to init electrum rpc client: {:?}", e))?;
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let db = bdk::sled::open(wallet_dir)?.open_tree(SLED_TREE_NAME)?;
let bdk_wallet = bdk::Wallet::new(
bdk::template::BIP84(key.clone(), KeychainKind::External),
Some(bdk::template::BIP84(key, KeychainKind::Internal)),
network,
db,
ElectrumBlockchain::from(client),
)?;
Ok(Self {
inner: Arc::new(Mutex::new(bdk_wallet)),
http_url: electrum_http_url,
rpc_url: electrum_rpc_url,
})
}
pub async fn balance(&self) -> Result<Amount> {
let balance = self
.inner
.lock()
.await
.get_balance()
.context("Failed to calculate Bitcoin balance")?;
Ok(Amount::from_sat(balance))
}
pub async fn new_address(&self) -> Result<Address> {
let address = self
.inner
.lock()
.await
.get_new_address()
.context("Failed to get new Bitcoin address")?;
Ok(address)
}
pub async fn get_tx(&self, txid: Txid) -> Result<Option<Transaction>> {
let tx = self.inner.lock().await.client().get_tx(&txid)?;
Ok(tx)
}
pub async fn transaction_fee(&self, txid: Txid) -> Result<Amount> {
let fees = self
.inner
.lock()
.await
.list_transactions(true)?
.iter()
.find(|tx| tx.txid == txid)
.ok_or_else(|| {
anyhow!("Could not find tx in bdk wallet when trying to determine fees")
})?
.fees;
Ok(Amount::from_sat(fees))
}
pub async fn sync(&self) -> Result<()> {
self.inner
.lock()
.await
.sync(noop_progress(), None)
.context("Failed to sync balance of Bitcoin wallet")?;
Ok(())
}
pub async fn send_to_address(
&self,
address: Address,
amount: Amount,
) -> Result<PartiallySignedTransaction> {
let wallet = self.inner.lock().await;
let mut tx_builder = wallet.build_tx();
tx_builder.add_recipient(address.script_pubkey(), amount.as_sat());
tx_builder.fee_rate(self.select_feerate());
let (psbt, _details) = tx_builder.finish()?;
Ok(psbt)
}
/// Calculates the maximum "giveable" amount of this wallet.
///
/// We define this as the maximum amount we can pay to a single output,
/// already accounting for the fees we need to spend to get the
/// transaction confirmed.
pub async fn max_giveable(&self, locking_script_size: usize) -> Result<Amount> {
let wallet = self.inner.lock().await;
let mut tx_builder = wallet.build_tx();
let dummy_script = Script::from(vec![0u8; locking_script_size]);
tx_builder.set_single_recipient(dummy_script);
tx_builder.drain_wallet();
tx_builder.fee_rate(self.select_feerate());
let (_, details) = tx_builder.finish().context("Failed to build transaction")?;
let max_giveable = details.sent - details.fees;
Ok(Amount::from_sat(max_giveable))
}
pub async fn get_network(&self) -> bitcoin::Network {
self.inner.lock().await.network()
}
/// Broadcast the given transaction to the network and emit a log statement
/// if done so successfully.
pub async fn broadcast(&self, transaction: Transaction, kind: &str) -> Result<Txid> {
let txid = transaction.txid();
self.inner
.lock()
.await
.broadcast(transaction)
.with_context(|| {
format!("Failed to broadcast Bitcoin {} transaction {}", kind, txid)
})?;
tracing::info!(%txid, "Published Bitcoin {} transaction", kind);
Ok(txid)
}
pub async fn sign_and_finalize(&self, psbt: PartiallySignedTransaction) -> Result<Transaction> {
let (signed_psbt, finalized) = self.inner.lock().await.sign(psbt, None)?;
if !finalized {
bail!("PSBT is not finalized")
}
let tx = signed_psbt.extract_tx();
Ok(tx)
}
pub async fn get_raw_transaction(&self, txid: Txid) -> Result<Transaction> {
self.get_tx(txid)
.await?
.ok_or_else(|| anyhow!("Could not get raw tx with id: {}", txid))
}
pub async fn watch_for_raw_transaction(&self, txid: Txid) -> Result<Transaction> {
tracing::debug!("watching for tx: {}", txid);
let tx = retry(ConstantBackoff::new(Duration::from_secs(1)), || async {
let client = Client::new(self.rpc_url.as_ref())
.map_err(|err| backoff::Error::Permanent(Error::ElectrumClient(err)))?;
let tx = client.transaction_get(&txid).map_err(|err| match err {
electrum_client::Error::Protocol(err) => {
tracing::debug!("Received protocol error {} from Electrum, retrying...", err);
backoff::Error::Transient(Error::NotYetMined)
}
err => backoff::Error::Permanent(Error::ElectrumClient(err)),
})?;
Result::<_, backoff::Error<Error>>::Ok(tx)
})
.await
.context("Transient errors should be retried")?;
Ok(tx)
}
pub async fn get_block_height(&self) -> Result<BlockHeight> {
let url = make_blocks_tip_height_url(&self.http_url)?;
let height = retry(ConstantBackoff::new(Duration::from_secs(1)), || async {
let height = reqwest::Client::new()
.request(Method::GET, url.clone())
.send()
.await
.map_err(Error::Io)?
.text()
.await
.map_err(Error::Io)?
.parse::<u32>()
.map_err(|err| backoff::Error::Permanent(Error::Parse(err)))?;
Result::<_, backoff::Error<Error>>::Ok(height)
})
.await
.context("Transient errors should be retried")?;
Ok(BlockHeight::new(height))
}
pub async fn transaction_block_height(&self, txid: Txid) -> Result<BlockHeight> {
let url = make_tx_status_url(&self.http_url, txid)?;
#[derive(Serialize, Deserialize, Debug, Clone)]
struct TransactionStatus {
block_height: Option<u32>,
confirmed: bool,
}
let height = retry(ConstantBackoff::new(Duration::from_secs(1)), || async {
let resp = reqwest::Client::new()
.request(Method::GET, url.clone())
.send()
.await
.map_err(|err| backoff::Error::Transient(Error::Io(err)))?;
let tx_status: TransactionStatus = resp
.json()
.await
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.map_err(|err| backoff::Error::Permanent(Error::JsonDeserialization(err)))?;
let block_height = tx_status
.block_height
.ok_or(backoff::Error::Transient(Error::NotYetMined))?;
Result::<_, backoff::Error<Error>>::Ok(block_height)
})
.await
.context("Transient errors should be retried")?;
Ok(BlockHeight::new(height))
}
pub async fn wait_for_transaction_finality(
&self,
txid: Txid,
execution_params: ExecutionParams,
) -> Result<()> {
let conf_target = execution_params.bitcoin_finality_confirmations;
tracing::info!(%txid, "Waiting for {} confirmation{} of Bitcoin transaction", conf_target, if conf_target > 1 { "s" } else { "" });
// Divide by 4 to not check too often yet still be aware of the new block early
// on.
let mut interval = interval(execution_params.bitcoin_avg_block_time / 4);
loop {
let tx_block_height = self.transaction_block_height(txid).await?;
tracing::debug!("tx_block_height: {:?}", tx_block_height);
let block_height = self.get_block_height().await?;
tracing::debug!("latest_block_height: {:?}", block_height);
if let Some(confirmations) = block_height.checked_sub(
tx_block_height
.checked_sub(BlockHeight::new(1))
.expect("transaction must be included in block with height >= 1"),
) {
tracing::debug!(%txid, "confirmations: {:?}", confirmations);
if u32::from(confirmations) >= conf_target {
break;
}
}
interval.tick().await;
}
Ok(())
}
/// Selects an appropriate [`FeeRate`] to be used for getting transactions
/// confirmed within a reasonable amount of time.
fn select_feerate(&self) -> FeeRate {
// TODO: This should obviously not be a const :)
FeeRate::from_sat_per_vb(5.0)
}
}
fn make_tx_status_url(base_url: &Url, txid: Txid) -> Result<Url> {
let url = base_url.join(&format!("tx/{}/status", txid))?;
Ok(url)
}
fn make_blocks_tip_height_url(base_url: &Url) -> Result<Url> {
let url = base_url.join("blocks/tip/height")?;
Ok(url)
}
#[cfg(test)]
mod tests {
use super::*;
use crate::cli::config::DEFAULT_ELECTRUM_HTTP_URL;
#[test]
fn create_tx_status_url_from_default_base_url_success() {
let base_url = DEFAULT_ELECTRUM_HTTP_URL.parse().unwrap();
let txid = Txid::default;
let url = make_tx_status_url(&base_url, txid()).unwrap();
assert_eq!(url.as_str(), "https://blockstream.info/testnet/api/tx/0000000000000000000000000000000000000000000000000000000000000000/status");
}
#[test]
fn create_block_tip_height_url_from_default_base_url_success() {
let base_url = DEFAULT_ELECTRUM_HTTP_URL.parse().unwrap();
let url = make_blocks_tip_height_url(&base_url).unwrap();
assert_eq!(
url.as_str(),
"https://blockstream.info/testnet/api/blocks/tip/height"
);
}
}