Most of coordinator Tributary retiry

Adds Event::SetRetired to validator-sets.

Emit TributaryRetired.

Replaces is_active_set, which made multiple network requests, with
is_retired_tributary, a DB read.

Performs most of the removals necessary upon TributaryRetired.

Still needs to clean up the actual Tributary/Tendermint tasks.

coordinator/src/db.rs

@@ -37,6 +37,9 @@ impl<D: Db> MainDb<D> {
   fn acive_tributaries_key() -> Vec<u8> {
     Self::main_key(b"active_tributaries", [])
   }
+  fn retired_tributary_key(set: ValidatorSet) -> Vec<u8> {
+    Self::main_key(b"retired_tributary", set.encode())
+  }
   pub fn active_tributaries<G: Get>(getter: &G) -> (Vec<u8>, Vec<TributarySpec>) {
     let bytes = getter.get(Self::acive_tributaries_key()).unwrap_or(vec![]);
     let mut bytes_ref: &[u8] = bytes.as_ref();
@@ -60,6 +63,25 @@ impl<D: Db> MainDb<D> {
     spec.write(&mut existing_bytes).unwrap();
     txn.put(key, existing_bytes);
   }
+  pub fn retire_tributary(txn: &mut D::Transaction<'_>, set: ValidatorSet) {
+    let mut active = Self::active_tributaries(txn).1;
+    for i in 0 .. active.len() {
+      if active[i].set() == set {
+        active.remove(i);
+        break;
+      }
+    }
+
+    let mut bytes = vec![];
+    for active in active {
+      active.write(&mut bytes).unwrap();
+    }
+    txn.put(Self::acive_tributaries_key(), bytes);
+    txn.put(Self::retired_tributary_key(set), []);
+  }
+  pub fn is_tributary_retired<G: Get>(getter: &G, set: ValidatorSet) -> bool {
+    getter.get(Self::retired_tributary_key(set)).is_some()
+  }
 
   fn signed_transaction_key(nonce: u32) -> Vec<u8> {
     Self::main_key(b"signed_transaction", nonce.to_le_bytes())

coordinator/src/main.rs

@@ -50,7 +50,7 @@ pub mod processors;
 use processors::Processors;
 
 mod substrate;
-use substrate::{SubstrateDb, is_active_set};
+use substrate::SubstrateDb;
 
 #[cfg(test)]
 pub mod tests;
@@ -67,18 +67,18 @@ pub enum TributaryEvent<D: Db, P: P2p> {
   TributaryRetired(ValidatorSet),
 }
 
+// TODO: Clean up the actual underlying Tributary/Tendermint tasks
+
 // Creates a new tributary and sends it to all listeners.
-// TODO: retire_tributary
 async fn add_tributary<D: Db, Pro: Processors, P: P2p>(
   db: D,
   key: Zeroizing<<Ristretto as Ciphersuite>::F>,
-  serai: &Serai,
   processors: &Pro,
   p2p: P,
   tributaries: &broadcast::Sender<TributaryEvent<D, P>>,
   spec: TributarySpec,
 ) {
-  if !is_active_set(serai, spec.set()).await {
+  if MainDb::<D>::is_tributary_retired(&db, spec.set()) {
     log::info!("not adding tributary {:?} since it's been retired", spec.set());
   }
 
@@ -363,12 +363,10 @@ async fn handle_processor_message<D: Db, P: P2p>(
 
   // If we have a relevant Tributary, check it's actually still relevant and has yet to be retired
   if let Some(relevant_tributary_value) = relevant_tributary {
-    if !is_active_set(
-      serai,
+    if MainDb::<D>::is_tributary_retired(
+      &txn,
       ValidatorSet { network: msg.network, session: relevant_tributary_value },
-    )
-    .await
-    {
+    ) {
       relevant_tributary = None;
     }
   }
@@ -382,8 +380,8 @@ async fn handle_processor_message<D: Db, P: P2p>(
     let Some(ActiveTributary { spec, tributary }) = tributaries.get(&relevant_tributary) else {
       // Since we don't, sleep for a fraction of a second and return false, signaling we didn't
       // handle this message
-      // At the start of the loop which calls this function, we'll check for new tributaries, making
-      // this eventually resolve
+      // At the start of the loop which calls this function, we'll check for new tributaries,
+      // making this eventually resolve
       sleep(Duration::from_millis(100)).await;
       return false;
     };
@@ -659,25 +657,22 @@ async fn handle_processor_messages<D: Db, Pro: Processors, P: P2p>(
   let mut tributaries = HashMap::new();
   loop {
     match tributary_event.try_recv() {
-      Ok(event) => {
-        match event {
-          TributaryEvent::NewTributary(tributary) => {
-            let set = tributary.spec.set();
-            assert_eq!(set.network, network);
-            tributaries.insert(set.session, tributary);
-          }
-          // TOOD
-          TributaryEvent::TributaryRetired(_) => todo!(),
+      Ok(event) => match event {
+        TributaryEvent::NewTributary(tributary) => {
+          let set = tributary.spec.set();
+          assert_eq!(set.network, network);
+          tributaries.insert(set.session, tributary);
         }
-      }
+        TributaryEvent::TributaryRetired(set) => {
+          tributaries.remove(&set.session);
+        }
+      },
       Err(mpsc::error::TryRecvError::Empty) => {}
       Err(mpsc::error::TryRecvError::Disconnected) => {
         panic!("handle_processor_messages tributary_event sender closed")
       }
     }
 
-    // TODO: Remove the Tributary if it's retired
-
     // TODO: Check this ID is sane (last handled ID or expected next ID)
     let msg = processors.recv(network).await;
     if handle_processor_message(&mut db, &key, &serai, &tributaries, network, &msg).await {
@@ -716,8 +711,9 @@ pub async fn handle_processors<D: Db, Pro: Processors, P: P2p>(
       TributaryEvent::NewTributary(tributary) => channels[&tributary.spec.set().network]
         .send(TributaryEvent::NewTributary(tributary))
         .unwrap(),
-      // TODO
-      TributaryEvent::TributaryRetired(_) => todo!(),
+      TributaryEvent::TributaryRetired(set) => {
+        channels[&set.network].send(TributaryEvent::TributaryRetired(set)).unwrap()
+      }
     };
   }
 }
@@ -737,6 +733,8 @@ pub async fn run<D: Db, Pro: Processors, P: P2p>(
     new_tributary_spec_send.send(spec).unwrap();
   }
 
+  let (tributary_retired_send, mut tributary_retired_recv) = mpsc::unbounded_channel();
+
   // Handle new Substrate blocks
   tokio::spawn(crate::substrate::scan_task(
     raw_db.clone(),
@@ -744,6 +742,7 @@ pub async fn run<D: Db, Pro: Processors, P: P2p>(
     processors.clone(),
     serai.clone(),
     new_tributary_spec_send,
+    tributary_retired_send,
   ));
 
   // Handle the Tributaries
@@ -756,11 +755,21 @@ pub async fn run<D: Db, Pro: Processors, P: P2p>(
   let tributary_event_listener_4 = tributary_event.subscribe();
   let tributary_event_listener_5 = tributary_event.subscribe();
 
+  // Emit TributaryEvent::TributaryRetired
+  tokio::spawn({
+    let tributary_event = tributary_event.clone();
+    async move {
+      loop {
+        let retired = tributary_retired_recv.recv().await.unwrap();
+        tributary_event.send(TributaryEvent::TributaryRetired(retired)).map_err(|_| ()).unwrap();
+      }
+    }
+  });
+
   // Spawn a task to further add Tributaries as needed
   tokio::spawn({
     let raw_db = raw_db.clone();
     let key = key.clone();
-    let serai = serai.clone();
     let processors = processors.clone();
     let p2p = p2p.clone();
     async move {
@@ -770,12 +779,11 @@ pub async fn run<D: Db, Pro: Processors, P: P2p>(
         tokio::spawn({
           let raw_db = raw_db.clone();
           let key = key.clone();
-          let serai = serai.clone();
           let processors = processors.clone();
           let p2p = p2p.clone();
           let tributary_event = tributary_event.clone();
           async move {
-            add_tributary(raw_db, key, &serai, &processors, p2p, &tributary_event, spec).await;
+            add_tributary(raw_db, key, &processors, p2p, &tributary_event, spec).await;
           }
         });
       }
@@ -790,14 +798,19 @@ pub async fn run<D: Db, Pro: Processors, P: P2p>(
     let tributaries = Arc::new(RwLock::new(HashMap::new()));
     tokio::spawn({
       let tributaries = tributaries.clone();
+      let mut set_to_genesis = HashMap::new();
       async move {
         loop {
           match tributary_event_listener_1.recv().await {
             Ok(TributaryEvent::NewTributary(tributary)) => {
+              set_to_genesis.insert(tributary.spec.set(), tributary.spec.genesis());
               tributaries.write().await.insert(tributary.spec.genesis(), tributary.tributary);
             }
-            // TODO
-            Ok(TributaryEvent::TributaryRetired(_)) => todo!(),
+            Ok(TributaryEvent::TributaryRetired(set)) => {
+              if let Some(genesis) = set_to_genesis.remove(&set) {
+                tributaries.write().await.remove(&genesis);
+              }
+            }
             Err(broadcast::error::RecvError::Lagged(_)) => {
               panic!("recognized_id lagged to handle tributary_event")
             }
@@ -807,7 +820,7 @@ pub async fn run<D: Db, Pro: Processors, P: P2p>(
       }
     });
 
-    move |network, genesis, id_type, id, nonce| {
+    move |set: ValidatorSet, genesis, id_type, id, nonce| {
       let mut raw_db = raw_db.clone();
       let key = key.clone();
       let tributaries = tributaries.clone();
@@ -815,10 +828,11 @@ pub async fn run<D: Db, Pro: Processors, P: P2p>(
         // The transactions for these are fired before the preprocesses are actually
         // received/saved, creating a race between Tributary ack and the availability of all
         // Preprocesses
-        // This waits until the necessary preprocess is available
+        // This waits until the necessary preprocess is available 0,
+        // TODO: Incorporate RecognizedIdType here?
         let get_preprocess = |raw_db, id| async move {
           loop {
-            let Some(preprocess) = MainDb::<D>::first_preprocess(raw_db, network, id) else {
+            let Some(preprocess) = MainDb::<D>::first_preprocess(raw_db, set.network, id) else {
               sleep(Duration::from_millis(100)).await;
               continue;
             };
@@ -853,11 +867,19 @@ pub async fn run<D: Db, Pro: Processors, P: P2p>(
 
           let tributaries = tributaries.read().await;
           let Some(tributary) = tributaries.get(&genesis) else {
+            // If we don't have this Tributary because it's retired, break and move on
+            if MainDb::<D>::is_tributary_retired(&raw_db, set) {
+              break;
+            }
+
             // This may happen if the task above is simply slow
             log::warn!("tributary we don't have yet came to consensus on an Batch");
             continue;
           };
-          // This is safe to perform multiple times and solely needs atomicity within itself
+          // This is safe to perform multiple times and solely needs atomicity with regards to
+          // itself
+          // TODO: Should this not take a TXN accordingly? It's best practice to take a txn, yet
+          // taking a txn fails to declare its achieved independence
           let mut txn = raw_db.txn();
           publish_signed_transaction(&mut txn, tributary, tx).await;
           txn.commit();
@@ -885,11 +907,7 @@ pub async fn run<D: Db, Pro: Processors, P: P2p>(
   tokio::spawn(p2p::heartbeat_tributaries_task(p2p.clone(), tributary_event_listener_3));
 
   // Handle P2P messages
-  tokio::spawn(p2p::handle_p2p_task(
-    Ristretto::generator() * key.deref(),
-    p2p,
-    tributary_event_listener_4,
-  ));
+  tokio::spawn(p2p::handle_p2p_task(p2p, tributary_event_listener_4));
 
   // Handle all messages from processors
   handle_processors(raw_db, key, serai, processors, tributary_event_listener_5).await;

coordinator/src/p2p.rs

@@ -8,8 +8,6 @@ use std::{
 
 use async_trait::async_trait;
 
-use ciphersuite::{Ciphersuite, Ristretto};
-
 use serai_db::Db;
 
 use tokio::{
@@ -434,19 +432,20 @@ pub async fn heartbeat_tributaries_task<D: Db, P: P2p>(
 }
 
 pub async fn handle_p2p_task<D: Db, P: P2p>(
-  our_key: <Ristretto as Ciphersuite>::G,
   p2p: P,
   mut tributary_event: broadcast::Receiver<TributaryEvent<D, P>>,
 ) {
-  let channels = Arc::new(RwLock::new(HashMap::new()));
+  let channels = Arc::new(RwLock::new(HashMap::<_, mpsc::UnboundedSender<Message<P>>>::new()));
   tokio::spawn({
     let p2p = p2p.clone();
     let channels = channels.clone();
+    let mut set_to_genesis = HashMap::new();
     async move {
       loop {
         match tributary_event.recv().await.unwrap() {
           TributaryEvent::NewTributary(tributary) => {
             let genesis = tributary.spec.genesis();
+            set_to_genesis.insert(tributary.spec.set(), genesis);
 
             let (send, mut recv) = mpsc::unbounded_channel();
             channels.write().await.insert(genesis, send);
@@ -455,7 +454,10 @@ pub async fn handle_p2p_task<D: Db, P: P2p>(
               let p2p = p2p.clone();
               async move {
                 loop {
-                  let mut msg: Message<P> = recv.recv().await.unwrap();
+                  let Some(mut msg) = recv.recv().await else {
+                    // Channel closure happens when the tributary retires
+                    break;
+                  };
                   match msg.kind {
                     P2pMessageKind::KeepAlive => {}
 
@@ -564,8 +566,11 @@ pub async fn handle_p2p_task<D: Db, P: P2p>(
               }
             });
           }
-          // TODO
-          TributaryEvent::TributaryRetired(_) => todo!(),
+          TributaryEvent::TributaryRetired(set) => {
+            if let Some(genesis) = set_to_genesis.remove(&set) {
+              channels.write().await.remove(&genesis);
+            }
+          }
         }
       }
     }

coordinator/src/substrate/mod.rs

@@ -260,6 +260,7 @@ async fn handle_block<D: Db, Pro: Processors>(
   db: &mut SubstrateDb<D>,
   key: &Zeroizing<<Ristretto as Ciphersuite>::F>,
   new_tributary_spec: &mpsc::UnboundedSender<TributarySpec>,
+  tributary_retired: &mpsc::UnboundedSender<ValidatorSet>,
   processors: &Pro,
   serai: &Serai,
   block: Block,
@@ -317,6 +318,26 @@ async fn handle_block<D: Db, Pro: Processors>(
     event_id += 1;
   }
 
+  for retired_set in serai.as_of(hash).validator_sets().set_retired_events().await? {
+    let ValidatorSetsEvent::SetRetired { set } = retired_set else {
+      panic!("SetRetired event wasn't SetRetired: {retired_set:?}");
+    };
+
+    if set.network == NetworkId::Serai {
+      continue;
+    }
+
+    if !SubstrateDb::<D>::handled_event(&db.0, hash, event_id) {
+      log::info!("found fresh set retired event {:?}", retired_set);
+      let mut txn = db.0.txn();
+      crate::MainDb::<D>::retire_tributary(&mut txn, set);
+      tributary_retired.send(set).unwrap();
+      SubstrateDb::<D>::handle_event(&mut txn, hash, event_id);
+      txn.commit();
+    }
+    event_id += 1;
+  }
+
   // Finally, tell the processor of acknowledged blocks/burns
   // This uses a single event as. unlike prior events which individually executed code, all
   // following events share data collection
@@ -336,6 +357,7 @@ async fn handle_new_blocks<D: Db, Pro: Processors>(
   db: &mut SubstrateDb<D>,
   key: &Zeroizing<<Ristretto as Ciphersuite>::F>,
   new_tributary_spec: &mpsc::UnboundedSender<TributarySpec>,
+  tributary_retired: &mpsc::UnboundedSender<ValidatorSet>,
   processors: &Pro,
   serai: &Serai,
   next_block: &mut u64,
@@ -354,6 +376,7 @@ async fn handle_new_blocks<D: Db, Pro: Processors>(
       db,
       key,
       new_tributary_spec,
+      tributary_retired,
       processors,
       serai,
       if b == latest_number {
@@ -380,6 +403,7 @@ pub async fn scan_task<D: Db, Pro: Processors>(
   processors: Pro,
   serai: Arc<Serai>,
   new_tributary_spec: mpsc::UnboundedSender<TributarySpec>,
+  tributary_retired: mpsc::UnboundedSender<ValidatorSet>,
 ) {
   log::info!("scanning substrate");
 
@@ -431,6 +455,7 @@ pub async fn scan_task<D: Db, Pro: Processors>(
       &mut db,
       &key,
       &new_tributary_spec,
+      &tributary_retired,
       &processors,
       &serai,
       &mut next_substrate_block,
@@ -446,58 +471,6 @@ pub async fn scan_task<D: Db, Pro: Processors>(
   }
 }
 
-/// Returns if a ValidatorSet has yet to be retired.
-pub async fn is_active_set(serai: &Serai, set: ValidatorSet) -> bool {
-  // TODO: Track this from the Substrate scanner to reduce our overhead? We'd only have a DB
-  // call, instead of a series of network requests
-  let serai = loop {
-    let Ok(serai) = serai.with_current_latest_block().await else {
-      log::error!("couldn't get the latest block hash from serai when checking if set is active");
-      sleep(Duration::from_secs(5)).await;
-      continue;
-    };
-    break serai.validator_sets();
-  };
-
-  let latest_session = loop {
-    let Ok(res) = serai.session(set.network).await else {
-      log::error!("couldn't get the latest session from serai when checking if set is active");
-      sleep(Duration::from_secs(5)).await;
-      continue;
-    };
-    // If the on-chain Session is None, then this Session is greater and therefore, for the
-    // purposes here, active
-    let Some(res) = res else { return true };
-    break res;
-  };
-
-  if latest_session.0 > set.session.0 {
-    // If we're on the Session after the Session after this Session, then this Session is
-    // definitively completed
-    if latest_session.0 > (set.session.0 + 1) {
-      return false;
-    } else {
-      // Since the next session has started, check its handover status
-      let keys = loop {
-        let Ok(res) = serai.keys(set).await else {
-          log::error!(
-            "couldn't get the keys for a session from serai when checking if set is active"
-          );
-          sleep(Duration::from_secs(5)).await;
-          continue;
-        };
-        break res;
-      };
-      // If the keys have been deleted, then this Tributary is retired
-      if keys.is_none() {
-        return false;
-      }
-    }
-  }
-
-  true
-}
-
 /// Gets the expected ID for the next Batch.
 pub(crate) async fn get_expected_next_batch(serai: &Serai, network: NetworkId) -> u32 {
   let mut first = true;

coordinator/src/tributary/handle.rs

@@ -426,7 +426,7 @@ pub(crate) async fn handle_application_tx<
       // Because this Batch has achieved synchrony, its batch ID should be authorized
       TributaryDb::<D>::recognize_topic(txn, genesis, Topic::Batch(batch));
       let nonce = NonceDecider::<D>::handle_batch(txn, genesis, batch);
-      recognized_id(spec.set().network, genesis, RecognizedIdType::Batch, batch, nonce).await;
+      recognized_id(spec.set(), genesis, RecognizedIdType::Batch, batch, nonce).await;
     }
 
     Transaction::SubstrateBlock(block) => {
@@ -438,7 +438,7 @@ pub(crate) async fn handle_application_tx<
       let nonces = NonceDecider::<D>::handle_substrate_block(txn, genesis, &plan_ids);
       for (nonce, id) in nonces.into_iter().zip(plan_ids.into_iter()) {
         TributaryDb::<D>::recognize_topic(txn, genesis, Topic::Sign(id));
-        recognized_id(spec.set().network, genesis, RecognizedIdType::Plan, id, nonce).await;
+        recognized_id(spec.set(), genesis, RecognizedIdType::Plan, id, nonce).await;
       }
     }
 

coordinator/src/tributary/scanner.rs

@@ -7,9 +7,7 @@ use ciphersuite::{Ciphersuite, Ristretto};
 
 use tokio::sync::broadcast;
 
-use serai_client::{
-  primitives::NetworkId, validator_sets::primitives::ValidatorSet, subxt::utils::Encoded, Serai,
-};
+use serai_client::{validator_sets::primitives::ValidatorSet, subxt::utils::Encoded, Serai};
 
 use tributary::{
   TransactionKind, Transaction as TributaryTransaction, Block, TributaryReader,
@@ -36,10 +34,10 @@ pub enum RecognizedIdType {
 }
 
 pub(crate) trait RIDTrait<FRid>:
-  Clone + Fn(NetworkId, [u8; 32], RecognizedIdType, [u8; 32], u32) -> FRid
+  Clone + Fn(ValidatorSet, [u8; 32], RecognizedIdType, [u8; 32], u32) -> FRid
 {
 }
-impl<FRid, F: Clone + Fn(NetworkId, [u8; 32], RecognizedIdType, [u8; 32], u32) -> FRid>
+impl<FRid, F: Clone + Fn(ValidatorSet, [u8; 32], RecognizedIdType, [u8; 32], u32) -> FRid>
   RIDTrait<FRid> for F
 {
 }

substrate/client/src/serai/validator_sets.rs

@@ -33,6 +33,13 @@ impl<'a> SeraiValidatorSets<'a> {
       .await
   }
 
+  pub async fn set_retired_events(&self) -> Result<Vec<ValidatorSetsEvent>, SeraiError> {
+    self
+      .0
+      .events::<ValidatorSets, _>(|event| matches!(event, ValidatorSetsEvent::SetRetired { .. }))
+      .await
+  }
+
   pub async fn session(&self, network: NetworkId) -> Result<Option<Session>, SeraiError> {
     self.0.storage(PALLET, "CurrentSession", Some(vec![scale_value(network)])).await
   }

substrate/in-instructions/pallet/src/lib.rs

@@ -174,7 +174,10 @@ pub mod pallet {
       // key is publishing `Batch`s. This should only happen once the current key has verified all
       // `Batch`s published by the prior key, meaning they are accepting the hand-over.
       if prior.is_some() && (!valid_by_prior) {
-        ValidatorSets::<T>::retire_session(network, Session(current_session.0 - 1));
+        ValidatorSets::<T>::retire_set(ValidatorSet {
+          network,
+          session: Session(current_session.0 - 1),
+        });
       }
 
       // check that this validator set isn't publishing a batch more than once per block

substrate/staking/pallet/src/lib.rs

@@ -13,7 +13,10 @@ pub mod pallet {
 
   use serai_primitives::{NetworkId, Amount, PublicKey};
 
-  use validator_sets_pallet::{primitives::Session, Config as VsConfig, Pallet as VsPallet};
+  use validator_sets_pallet::{
+    primitives::{Session, ValidatorSet},
+    Config as VsConfig, Pallet as VsPallet,
+  };
   use pallet_session::{Config as SessionConfig, SessionManager};
 
   #[pallet::error]
@@ -183,7 +186,12 @@ pub mod pallet {
       Some(VsPallet::<T>::select_validators(NetworkId::Serai))
     }
 
-    fn end_session(_end_index: u32) {}
+    fn end_session(end_index: u32) {
+      VsPallet::<T>::retire_set(ValidatorSet {
+        network: NetworkId::Serai,
+        session: Session(end_index),
+      })
+    }
 
     fn start_session(_start_index: u32) {}
   }

substrate/validator-sets/pallet/src/lib.rs

@@ -235,6 +235,7 @@ pub mod pallet {
   pub enum Event<T: Config> {
     NewSet { set: ValidatorSet },
     KeyGen { set: ValidatorSet, key_pair: KeyPair },
+    SetRetired { set: ValidatorSet },
   }
 
   impl<T: Config> Pallet<T> {
@@ -592,10 +593,10 @@ pub mod pallet {
       Self::participants(network).into()
     }
 
-    pub fn retire_session(network: NetworkId, session: Session) {
-      let set = ValidatorSet { network, session };
+    pub fn retire_set(set: ValidatorSet) {
       MuSigKeys::<T>::remove(set);
       Keys::<T>::remove(set);
+      Pallet::<T>::deposit_event(Event::SetRetired { set });
     }
 
     /// Take the amount deallocatable.