change: Append block producer to log on block finalization

toolkit/pallets/block-production-log/src/lib.rs

@@ -35,6 +35,9 @@ pub mod pallet {
 	#[pallet::unbounded]
 	pub type Log<T: Config> = StorageValue<_, Vec<(Slot, T::BlockProducerId)>, ValueQuery>;
 
+	#[pallet::storage]
+	pub type CurrentProducer<T: Config> = StorageValue<_, T::BlockProducerId, OptionQuery>;
+
 	/// This storage is used to prevent calling `append` multiple times for the same block or for past blocks.
 	#[pallet::storage]
 	pub type LatestBlock<T: Config> = StorageValue<_, BlockNumberFor<T>, OptionQuery>;
@@ -86,7 +89,19 @@ pub mod pallet {
 			}?;
 			LatestBlock::<T>::put(current_block);
 
-			Ok(Log::<T>::append((T::current_slot(), block_producer_id)))
+			Ok(CurrentProducer::<T>::put(block_producer_id))
+		}
+	}
+
+	#[pallet::hooks]
+	impl<T: Config> Hooks<BlockNumberFor<T>> for Pallet<T> {
+		fn on_finalize(block: BlockNumberFor<T>) {
+			let block_producer_id =
+				CurrentProducer::<T>::take().expect("Author is set before on_finalize; qed");
+
+			log::info!("👷 Block {block:?} producer is {block_producer_id:?}");
+
+			Log::<T>::append((T::current_slot(), block_producer_id))
 		}
 	}
 
@@ -96,5 +111,15 @@ pub mod pallet {
 			Log::<T>::put(to_retain);
 			to_return
 		}
+
+		pub fn peek_prefix<'a>(slot: Slot) -> impl Iterator<Item = (Slot, T::BlockProducerId)> {
+			Log::<T>::get().into_iter().filter(move |(s, _)| s <= &slot)
+		}
+
+		pub fn drop_prefix<'a>(slot: Slot) {
+			let entries_left: Vec<_> =
+				Log::<T>::get().into_iter().filter(move |(s, _)| s > &slot).collect();
+			Log::<T>::put(entries_left);
+		}
 	}
 }