-
Notifications
You must be signed in to change notification settings - Fork 93
Commit
This commit does not belong to any branch on this repository, and may belong to a fork outside of the repository.
Merge pull request #103 from TheBlueMatt/main
Make SpendableOutput claims more robust
- Loading branch information
Showing
2 changed files
with
181 additions
and
30 deletions.
There are no files selected for viewing
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Original file line number | Diff line number | Diff line change |
---|---|---|
@@ -0,0 +1,127 @@ | ||
use std::io::{Read, Seek, SeekFrom}; | ||
use std::path::PathBuf; | ||
use std::sync::Arc; | ||
use std::time::Duration; | ||
use std::{fs, io}; | ||
|
||
use lightning::chain::chaininterface::{BroadcasterInterface, ConfirmationTarget, FeeEstimator}; | ||
use lightning::chain::keysinterface::{EntropySource, KeysManager, SpendableOutputDescriptor}; | ||
use lightning::util::logger::Logger; | ||
use lightning::util::persist::KVStorePersister; | ||
use lightning::util::ser::{Readable, WithoutLength}; | ||
|
||
use bitcoin::secp256k1::Secp256k1; | ||
|
||
use crate::hex_utils; | ||
use crate::BitcoindClient; | ||
use crate::FilesystemLogger; | ||
use crate::FilesystemPersister; | ||
|
||
/// If we have any pending claimable outputs, we should slowly sweep them to our Bitcoin Core | ||
/// wallet. We technically don't need to do this - they're ours to spend when we want and can just | ||
/// use them to build new transactions instead, but we cannot feed them direclty into Bitcoin | ||
/// Core's wallet so we have to sweep. | ||
/// | ||
/// Note that this is unececssary for [`SpendableOutputDescriptor::StaticOutput`]s, which *do* have | ||
/// an associated secret key we could simply import into Bitcoin Core's wallet, but for consistency | ||
/// we don't do that here either. | ||
pub(crate) async fn periodic_sweep( | ||
ldk_data_dir: String, keys_manager: Arc<KeysManager>, logger: Arc<FilesystemLogger>, | ||
persister: Arc<FilesystemPersister>, bitcoind_client: Arc<BitcoindClient>, | ||
) { | ||
// Regularly claim outputs which are exclusively spendable by us and send them to Bitcoin Core. | ||
// Note that if you more tightly integrate your wallet with LDK you may not need to do this - | ||
// these outputs can just be treated as normal outputs during coin selection. | ||
let pending_spendables_dir = | ||
format!("{}/{}", crate::PENDING_SPENDABLE_OUTPUT_DIR, ldk_data_dir); | ||
let processing_spendables_dir = format!("{}/processing_spendable_outputs", ldk_data_dir); | ||
let spendables_dir = format!("{}/spendable_outputs", ldk_data_dir); | ||
|
||
// We batch together claims of all spendable outputs generated each day, however only after | ||
// batching any claims of spendable outputs which were generated prior to restart. On a mobile | ||
// device we likely won't ever be online for more than a minute, so we have to ensure we sweep | ||
// any pending claims on startup, but for an always-online node you may wish to sweep even less | ||
// frequently than this (or move the interval await to the top of the loop)! | ||
// | ||
// There is no particular rush here, we just have to ensure funds are availably by the time we | ||
// need to send funds. | ||
let mut interval = tokio::time::interval(Duration::from_secs(60 * 60 * 24)); | ||
|
||
loop { | ||
interval.tick().await; // Note that the first tick completes immediately | ||
if let Ok(dir_iter) = fs::read_dir(&pending_spendables_dir) { | ||
// Move any spendable descriptors from pending folder so that we don't have any | ||
// races with new files being added. | ||
for file_res in dir_iter { | ||
let file = file_res.unwrap(); | ||
// Only move a file if its a 32-byte-hex'd filename, otherwise it might be a | ||
// temporary file. | ||
if file.file_name().len() == 64 { | ||
fs::create_dir_all(&processing_spendables_dir).unwrap(); | ||
let mut holding_path = PathBuf::new(); | ||
holding_path.push(&processing_spendables_dir); | ||
holding_path.push(&file.file_name()); | ||
fs::rename(file.path(), holding_path).unwrap(); | ||
} | ||
} | ||
// Now concatenate all the pending files we moved into one file in the | ||
// `spendable_outputs` directory and drop the processing directory. | ||
let mut outputs = Vec::new(); | ||
if let Ok(processing_iter) = fs::read_dir(&processing_spendables_dir) { | ||
for file_res in processing_iter { | ||
outputs.append(&mut fs::read(file_res.unwrap().path()).unwrap()); | ||
} | ||
} | ||
if !outputs.is_empty() { | ||
let key = hex_utils::hex_str(&keys_manager.get_secure_random_bytes()); | ||
persister | ||
.persist(&format!("spendable_outputs/{}", key), &WithoutLength(&outputs)) | ||
.unwrap(); | ||
fs::remove_dir_all(&processing_spendables_dir).unwrap(); | ||
} | ||
} | ||
// Iterate over all the sets of spendable outputs in `spendables_dir` and try to claim | ||
// them. | ||
// Note that here we try to claim each set of spendable outputs over and over again | ||
// forever, even long after its been claimed. While this isn't an issue per se, in practice | ||
// you may wish to track when the claiming transaction has confirmed and remove the | ||
// spendable outputs set. You may also wish to merge groups of unspent spendable outputs to | ||
// combine batches. | ||
if let Ok(dir_iter) = fs::read_dir(&spendables_dir) { | ||
for file_res in dir_iter { | ||
let mut outputs: Vec<SpendableOutputDescriptor> = Vec::new(); | ||
let mut file = fs::File::open(file_res.unwrap().path()).unwrap(); | ||
loop { | ||
// Check if there are any bytes left to read, and if so read a descriptor. | ||
match file.read_exact(&mut [0; 1]) { | ||
Ok(_) => { | ||
file.seek(SeekFrom::Current(-1)).unwrap(); | ||
} | ||
Err(e) if e.kind() == io::ErrorKind::UnexpectedEof => break, | ||
Err(e) => Err(e).unwrap(), | ||
} | ||
outputs.push(Readable::read(&mut file).unwrap()); | ||
} | ||
let destination_address = bitcoind_client.get_new_address().await; | ||
let output_descriptors = &outputs.iter().map(|a| a).collect::<Vec<_>>(); | ||
let tx_feerate = | ||
bitcoind_client.get_est_sat_per_1000_weight(ConfirmationTarget::Background); | ||
if let Ok(spending_tx) = keys_manager.spend_spendable_outputs( | ||
output_descriptors, | ||
Vec::new(), | ||
destination_address.script_pubkey(), | ||
tx_feerate, | ||
&Secp256k1::new(), | ||
) { | ||
// Note that, most likely, we've already sweeped this set of outputs | ||
// and they're already confirmed on-chain, so this broadcast will fail. | ||
bitcoind_client.broadcast_transaction(&spending_tx); | ||
} else { | ||
lightning::log_error!( | ||
logger, | ||
"Failed to sweep spendable outputs! This may indicate the outputs are dust. Will try again in a day."); | ||
} | ||
} | ||
} | ||
} | ||
} |