Implement saving BeaconChain on client drop

beacon_node/beacon_chain/src/beacon_chain.rs

@@ -336,6 +336,11 @@ impl<T: BeaconChainTypes> BeaconChain<T> {
         self.canonical_head.read()
     }
 
+    /// Returns the slot of the highest block in the canonical chain.
+    pub fn best_slot(&self) -> Slot {
+        self.canonical_head.read().beacon_block.slot
+    }
+
     /// Updates the canonical `BeaconState` with the supplied state.
     ///
     /// Advances the chain forward to the present slot. This method is better than just setting

beacon_node/client/src/beacon_chain_types.rs

@@ -5,6 +5,7 @@ use beacon_chain::{
     BeaconChain, BeaconChainTypes,
 };
 use fork_choice::ForkChoice;
+use slog::{info, Logger};
 use slot_clock::SlotClock;
 use std::sync::Arc;
 use tree_hash::TreeHash;
@@ -14,7 +15,7 @@ use types::{
 
 /// Provides a new, initialized `BeaconChain`
 pub trait InitialiseBeaconChain<T: BeaconChainTypes> {
-    fn initialise_beacon_chain(store: Arc<T::Store>) -> BeaconChain<T>;
+    fn initialise_beacon_chain(store: Arc<T::Store>, log: Logger) -> BeaconChain<T>;
 }
 
 /// A testnet-suitable BeaconChainType, using `MemoryStore`.
@@ -29,8 +30,8 @@ impl BeaconChainTypes for TestnetMemoryBeaconChainTypes {
 }
 
 impl<T: BeaconChainTypes> InitialiseBeaconChain<T> for TestnetMemoryBeaconChainTypes {
-    fn initialise_beacon_chain(store: Arc<T::Store>) -> BeaconChain<T> {
+    fn initialise_beacon_chain(store: Arc<T::Store>, log: Logger) -> BeaconChain<T> {
-        maybe_load_from_store_for_testnet::<_, T::Store, T::EthSpec>(store)
+        maybe_load_from_store_for_testnet::<_, T::Store, T::EthSpec>(store, log)
     }
 }
 
@@ -46,20 +47,31 @@ impl BeaconChainTypes for TestnetDiskBeaconChainTypes {
 }
 
 impl<T: BeaconChainTypes> InitialiseBeaconChain<T> for TestnetDiskBeaconChainTypes {
-    fn initialise_beacon_chain(store: Arc<T::Store>) -> BeaconChain<T> {
+    fn initialise_beacon_chain(store: Arc<T::Store>, log: Logger) -> BeaconChain<T> {
-        maybe_load_from_store_for_testnet::<_, T::Store, T::EthSpec>(store)
+        maybe_load_from_store_for_testnet::<_, T::Store, T::EthSpec>(store, log)
     }
 }
 
 /// Loads a `BeaconChain` from `store`, if it exists. Otherwise, create a new chain from genesis.
-fn maybe_load_from_store_for_testnet<T, U: Store, V: EthSpec>(store: Arc<U>) -> BeaconChain<T>
+fn maybe_load_from_store_for_testnet<T, U: Store, V: EthSpec>(
+    store: Arc<U>,
+    log: Logger,
+) -> BeaconChain<T>
 where
     T: BeaconChainTypes<Store = U>,
     T::ForkChoice: ForkChoice<U>,
 {
     if let Ok(Some(beacon_chain)) = BeaconChain::from_store(store.clone()) {
+        info!(
+            log,
+            "Loaded BeaconChain from store";
+            "slot" => beacon_chain.state.read().slot,
+            "best_slot" => beacon_chain.best_slot(),
+        );
+
         beacon_chain
     } else {
+        info!(log, "Initializing new BeaconChain from genesis");
         let spec = T::EthSpec::spec();
 
         let state_builder =

beacon_node/client/src/lib.rs

@@ -28,7 +28,7 @@ pub struct Client<T: BeaconChainTypes> {
     /// Configuration for the lighthouse client.
     _config: ClientConfig,
     /// The beacon chain for the running client.
-    _beacon_chain: Arc<BeaconChain<T>>,
+    beacon_chain: Arc<BeaconChain<T>>,
     /// Reference to the network service.
     pub network: Arc<NetworkService<T>>,
     /// Signal to terminate the RPC server.
@@ -57,7 +57,7 @@ where
         let store = Arc::new(store);
 
         // Load a `BeaconChain` from the store, or create a new one if it does not exist.
-        let beacon_chain = Arc::new(T::initialise_beacon_chain(store));
+        let beacon_chain = Arc::new(T::initialise_beacon_chain(store, log.clone()));
 
         if beacon_chain.read_slot_clock().is_none() {
             panic!("Cannot start client before genesis!")
@@ -151,7 +151,7 @@ where
 
         Ok(Client {
             _config: config,
-            _beacon_chain: beacon_chain,
+            beacon_chain,
             http_exit_signal,
             rpc_exit_signal,
             slot_timer_exit_signal: Some(slot_timer_exit_signal),
@@ -162,6 +162,14 @@ where
     }
 }
 
+impl<T: BeaconChainTypes> Drop for Client<T> {
+    fn drop(&mut self) {
+        // Save the beacon chain to it's store before dropping.
+        let _result = self.beacon_chain.persist();
+        dbg!("Saved BeaconChain to store");
+    }
+}
+
 fn do_state_catchup<T: BeaconChainTypes>(chain: &Arc<BeaconChain<T>>, log: &slog::Logger) {
     if let Some(genesis_height) = chain.slots_since_genesis() {
         let result = chain.catchup_state();