feat(consensus): add decision fn to consensus context API (#387)

This is how consensus updates the rest of the node when a new block has been decided.

crates/sequencing/papyrus_consensus/src/manager.rs

@@ -9,12 +9,11 @@ use std::time::Duration;
 
 use futures::channel::{mpsc, oneshot};
 use futures::{Stream, StreamExt};
-use papyrus_common::metrics as papyrus_metrics;
 use papyrus_network::network_manager::ReportSender;
 use papyrus_protobuf::consensus::{ConsensusMessage, Proposal};
 use papyrus_protobuf::converters::ProtobufConversionError;
 use starknet_api::block::{BlockHash, BlockNumber};
-use tracing::{debug, info, instrument};
+use tracing::{debug, instrument};
 
 use crate::single_height_consensus::SingleHeightConsensus;
 use crate::types::{
@@ -52,13 +51,7 @@ where
         let decision = manager
             .run_height(&mut context, current_height, validator_id, &mut network_receiver)
             .await?;
-
-        info!(
-            "Finished consensus for height: {current_height}. Agreed on block with id: {:x}",
-            decision.block.id().0
-        );
-        debug!("Decision: {:?}", decision);
-        metrics::gauge!(papyrus_metrics::PAPYRUS_CONSENSUS_HEIGHT, current_height.0 as f64);
+        context.notify_decision(decision.block, decision.precommits).await?;
         current_height = current_height.unchecked_next();
     }
 }

crates/sequencing/papyrus_consensus/src/manager_test.rs

@@ -71,6 +71,12 @@ mock! {
             content_receiver: mpsc::Receiver<Transaction>,
             fin_receiver: oneshot::Receiver<BlockHash>,
         ) -> Result<(), ConsensusError>;
+
+        async fn notify_decision(
+            &self,
+            block: TestBlock,
+            precommits: Vec<Vote>,
+        ) -> Result<(), ConsensusError>;
     }
 }
 

crates/sequencing/papyrus_consensus/src/papyrus_consensus_context.rs

@@ -9,15 +9,16 @@ use async_trait::async_trait;
 use futures::channel::{mpsc, oneshot};
 use futures::sink::SinkExt;
 use futures::StreamExt;
+use papyrus_common::metrics::PAPYRUS_CONSENSUS_HEIGHT;
 use papyrus_network::network_manager::BroadcastSubscriberSender;
-use papyrus_protobuf::consensus::{ConsensusMessage, Proposal};
+use papyrus_protobuf::consensus::{ConsensusMessage, Proposal, Vote};
 use papyrus_storage::body::BodyStorageReader;
 use papyrus_storage::header::HeaderStorageReader;
 use papyrus_storage::{StorageError, StorageReader};
 use starknet_api::block::{BlockHash, BlockNumber};
 use starknet_api::core::ContractAddress;
 use starknet_api::transaction::Transaction;
-use tracing::{debug, debug_span, Instrument};
+use tracing::{debug, debug_span, info, Instrument};
 
 use crate::types::{ConsensusBlock, ConsensusContext, ConsensusError, ProposalInit, ValidatorId};
 use crate::ProposalWrapper;
@@ -225,6 +226,20 @@ impl ConsensusContext for PapyrusConsensusContext {
         );
         Ok(())
     }
+
+    async fn notify_decision(
+        &self,
+        block: Self::Block,
+        precommits: Vec<Vote>,
+    ) -> Result<(), ConsensusError> {
+        let height = precommits[0].height;
+        info!(
+            "Finished consensus for height: {height}. Agreed on block with id: {:x}",
+            block.id().0
+        );
+        metrics::gauge!(PAPYRUS_CONSENSUS_HEIGHT, height as f64);
+        Ok(())
+    }
 }
 
 const SLEEP_BETWEEN_CHECK_FOR_BLOCK: Duration = Duration::from_secs(10);

crates/sequencing/papyrus_consensus/src/test_utils.rs

@@ -1,7 +1,7 @@
 use async_trait::async_trait;
 use futures::channel::{mpsc, oneshot};
 use mockall::mock;
-use papyrus_protobuf::consensus::ConsensusMessage;
+use papyrus_protobuf::consensus::{ConsensusMessage, Vote};
 use starknet_api::block::{BlockHash, BlockNumber};
 
 use crate::types::{ConsensusBlock, ConsensusContext, ConsensusError, ProposalInit, ValidatorId};
@@ -57,5 +57,11 @@ mock! {
             content_receiver: mpsc::Receiver<u32>,
             fin_receiver: oneshot::Receiver<BlockHash>,
         ) -> Result<(), ConsensusError>;
+
+        async fn notify_decision(
+            &self,
+            block: TestBlock,
+            precommits: Vec<Vote>,
+        ) -> Result<(), ConsensusError>;
     }
 }

crates/sequencing/papyrus_consensus/src/types.rs

@@ -135,6 +135,16 @@ pub trait ConsensusContext {
         content_receiver: mpsc::Receiver<<Self::Block as ConsensusBlock>::ProposalChunk>,
         fin_receiver: oneshot::Receiver<BlockHash>,
     ) -> Result<(), ConsensusError>;
+
+    /// Update the context that a decision has been reached for a given height.
+    /// - `block` identifies the decision.
+    /// - `precommits` - All precommits must be for the same `(block.id(), height, round)` and form
+    ///   a quorum (>2/3 of the voting power) for this height.
+    async fn notify_decision(
+        &self,
+        block: Self::Block,
+        precommits: Vec<Vote>,
+    ) -> Result<(), ConsensusError>;
 }
 
 #[derive(PartialEq)]