Add key management to the scheduler

This commit is contained in:
Luke Parker 2024-08-29 15:26:04 -04:00
parent 920303e1b4
commit 8db76ed67c
3 changed files with 62 additions and 8 deletions

View file

@ -1,12 +1,17 @@
use core::marker::PhantomData;
use scale::Encode;
use borsh::{BorshSerialize, BorshDeserialize};
use serai_db::{Get, DbTxn, create_db};
use primitives::{EncodableG, Eventuality, EventualityTracker};
use crate::{ScannerFeed, KeyFor, EventualityFor};
// The DB macro doesn't support `BorshSerialize + BorshDeserialize` as a bound, hence this.
trait Borshy: BorshSerialize + BorshDeserialize {}
impl<T: BorshSerialize + BorshDeserialize> Borshy for T {}
create_db!(
ScannerEventuality {
// The next block to check for resolving eventualities
@ -15,6 +20,8 @@ create_db!(
LatestHandledNotableBlock: () -> u64,
SerializedEventualities: <K: Encode>(key: K) -> Vec<u8>,
RetiredKey: <K: Borshy>(block_number: u64) -> K,
}
);
@ -51,7 +58,6 @@ impl<S: ScannerFeed> EventualityDb<S> {
}
SerializedEventualities::set(txn, EncodableG(key), &serialized);
}
pub(crate) fn eventualities(
getter: &impl Get,
key: KeyFor<S>,
@ -66,4 +72,19 @@ impl<S: ScannerFeed> EventualityDb<S> {
}
res
}
pub(crate) fn retire_key(txn: &mut impl DbTxn, block_number: u64, key: KeyFor<S>) {
assert!(
RetiredKey::get::<EncodableG<KeyFor<S>>>(txn, block_number).is_none(),
"retiring multiple keys within the same block"
);
RetiredKey::set(txn, block_number, &EncodableG(key));
}
pub(crate) fn take_retired_key(txn: &mut impl DbTxn, block_number: u64) -> Option<KeyFor<S>> {
let res = RetiredKey::get::<EncodableG<KeyFor<S>>>(txn, block_number).map(|res| res.0);
if res.is_some() {
RetiredKey::del::<EncodableG<KeyFor<S>>>(txn, block_number);
}
res
}
}

View file

@ -248,6 +248,11 @@ impl<D: Db, S: ScannerFeed, Sch: Scheduler<S>> ContinuallyRan for EventualityTas
let mut outputs = received_external_outputs;
for key in &keys {
// If this is the key's activation block, activate it
if key.activation_block_number == b {
self.scheduler.activate_key(&mut txn, key.key);
}
let completed_eventualities = {
let mut eventualities = EventualityDb::<S>::eventualities(&txn, key.key);
let completed_eventualities = block.check_for_eventuality_resolutions(&mut eventualities);
@ -349,11 +354,18 @@ impl<D: Db, S: ScannerFeed, Sch: Scheduler<S>> ContinuallyRan for EventualityTas
// Retire this key `WINDOW_LENGTH` blocks in the future to ensure the scan task never
// has a malleable view of the keys.
ScannerGlobalDb::<S>::retire_key(&mut txn, b + S::WINDOW_LENGTH, key.key);
let retire_at = b + S::WINDOW_LENGTH;
ScannerGlobalDb::<S>::retire_key(&mut txn, retire_at, key.key);
EventualityDb::<S>::retire_key(&mut txn, retire_at, key.key);
}
}
}
// If we retired any key at this block, retire it within the scheduler
if let Some(key) = EventualityDb::<S>::take_retired_key(&mut txn, b) {
self.scheduler.retire_key(&mut txn, key);
}
// Update the next-to-check block
EventualityDb::<S>::set_next_to_check_for_eventualities_block(&mut txn, next_to_check);

View file

@ -137,6 +137,12 @@ pub trait ScannerFeed: 'static + Send + Sync + Clone {
Ok(block)
}
/// The dust threshold for the specified coin.
///
/// This MUST be constant. Serai MUST NOT create internal outputs worth less than this. This
/// SHOULD be a value worth handling at a human level.
fn dust(&self, coin: Coin) -> Amount;
/// The cost to aggregate an input as of the specified block.
///
/// This is defined as the transaction fee for a 2-input, 1-output transaction.
@ -145,12 +151,6 @@ pub trait ScannerFeed: 'static + Send + Sync + Clone {
coin: Coin,
reference_block: &Self::Block,
) -> Result<Amount, Self::EphemeralError>;
/// The dust threshold for the specified coin.
///
/// This MUST be constant. Serai MUST NOT create internal outputs worth less than this. This
/// SHOULD be a value worth handling at a human level.
fn dust(&self, coin: Coin) -> Amount;
}
type KeyFor<S> = <<S as ScannerFeed>::Block as Block>::Key;
@ -187,6 +187,27 @@ pub struct SchedulerUpdate<S: ScannerFeed> {
/// The object responsible for accumulating outputs and planning new transactions.
pub trait Scheduler<S: ScannerFeed>: 'static + Send {
/// Activate a key.
///
/// This SHOULD setup any necessary database structures. This SHOULD NOT cause the new key to
/// be used as the primary key. The multisig rotation time clearly establishes its steps.
fn activate_key(&mut self, txn: &mut impl DbTxn, key: KeyFor<S>);
/// Flush all outputs within a retiring key to the new key.
///
/// When a key is activated, the existing multisig should retain its outputs and utility for a
/// certain time period. With `flush_key`, all outputs should be directed towards fulfilling some
/// obligation or the `new_key`. Every output MUST be connected to an Eventuality. If a key no
/// longer has active Eventualities, it MUST be able to be retired.
// TODO: Call this
fn flush_key(&mut self, txn: &mut impl DbTxn, retiring_key: KeyFor<S>, new_key: KeyFor<S>);
/// Retire a key as it'll no longer be used.
///
/// Any key retired MUST NOT still have outputs associated with it. This SHOULD be a NOP other
/// than any assertions and database cleanup.
fn retire_key(&mut self, txn: &mut impl DbTxn, key: KeyFor<S>);
/// Accumulate outputs into the scheduler, yielding the Eventualities now to be scanned for.
///
/// The `Vec<u8>` used as the key in the returned HashMap should be the encoded key the