add syncer

Cargo.lock

@@ -670,10 +670,13 @@ dependencies = [
  "cuprate-p2p",
  "dandelion-tower",
  "futures",
+ "hex",
  "monero-p2p",
  "monero-serai",
+ "thiserror",
  "tokio",
  "tower",
+ "tracing",
 ]
 
 [[package]]

binaries/cuprated/Cargo.toml

@@ -25,4 +25,7 @@ tower = { workspace = true }
 
 # Utils
 bytes = { workspace = true }
+tracing = { workspace = true }
+thiserror = { workspace = true }
+hex = { workspace = true }
 

binaries/cuprated/src/blockchain.rs

@@ -1,62 +1 @@
-//! # The Syncer
-//!
-//! The syncer is the part of Cuprate that handles keeping the blockchain state, it handles syncing if
-//! we have fallen behind, and it handles incoming blocks.
-use cuprate_blockchain::service::DatabaseWriteHandle;
-use monero_serai::{block::Block, transaction::Transaction};
-use tokio::sync::mpsc;
-use tower::Service;
-
-use cuprate_consensus::{
-    BlockChainContextRequest, BlockChainContextResponse, ExtendedConsensusError,
-    VerifyBlockRequest, VerifyBlockResponse,
-};
-use monero_p2p::handles::ConnectionHandle;
-
-pub struct IncomingBlock {
-    block: Block,
-    included_txs: Vec<Transaction>,
-    peer_handle: ConnectionHandle,
-}
-
-/// A response to an [`IncomingBlock`]
-pub enum IncomingBlockResponse {
-    /// We are missing these transactions from the block.
-    MissingTransactions(Vec<[u8; 32]>),
-    /// A generic ok response.
-    Ok,
-}
-
-struct BlockBatch;
-
-/// The blockchain.
-///
-/// This struct represents the task that syncs and maintains Cuprate's blockchain state.
-pub struct Blockchain<C, BV> {
-    /// The blockchain context service.
-    ///
-    /// This service handles keeping all the data needed to verify new blocks.
-    context_svc: C,
-    /// The block verifier service, handles block verification.
-    block_verifier_svc: BV,
-
-    /// The blockchain database write handle.
-    database_svc: DatabaseWriteHandle,
-
-    incoming_block_rx: mpsc::Receiver<IncomingBlock>,
-
-    incoming_block_batch_rx: mpsc::Receiver<BlockBatch>,
-}
-
-impl<C, BV> Blockchain<C, BV>
-where
-    C: Service<
-        BlockChainContextRequest,
-        Response = BlockChainContextResponse,
-        Error = tower::BoxError,
-    >,
-    C::Future: Send + 'static,
-    BV: Service<VerifyBlockRequest, Response = VerifyBlockResponse, Error = ExtendedConsensusError>,
-    BV::Future: Send + 'static,
-{
-}
+mod syncer;

binaries/cuprated/src/blockchain/syncer.rs

@@ -0,0 +1,122 @@
+use std::time::Duration;
+
+use futures::StreamExt;
+use tokio::{sync::mpsc, time::sleep};
+use tower::{Service, ServiceExt};
+use tracing::instrument;
+
+use cuprate_consensus::{BlockChainContext, BlockChainContextRequest, BlockChainContextResponse};
+use cuprate_p2p::{
+    block_downloader::{BlockBatch, BlockDownloaderConfig, ChainSvcRequest, ChainSvcResponse},
+    NetworkInterface,
+};
+use monero_p2p::network_zones::ClearNet;
+
+/// An error returned from the [`syncer`].
+#[derive(Debug, thiserror::Error)]
+enum SyncerError {
+    #[error("Incoming block channel closed.")]
+    IncomingBlockChannelClosed,
+    #[error("One of our services returned an error: {0}.")]
+    ServiceError(#[from] tower::BoxError),
+}
+
+#[instrument(level = "debug", skip_all)]
+async fn syncer<C, CN>(
+    mut context_svc: C,
+    our_chain: CN,
+    clearnet_interface: NetworkInterface<ClearNet>,
+    incoming_block_batch_tx: mpsc::Sender<BlockBatch>,
+    block_downloader_config: BlockDownloaderConfig,
+) -> Result<(), SyncerError>
+where
+    C: Service<
+        BlockChainContextRequest,
+        Response = BlockChainContextResponse,
+        Error = tower::BoxError,
+    >,
+    C::Future: Send + 'static,
+    CN: Service<ChainSvcRequest, Response = ChainSvcResponse, Error = tower::BoxError>
+        + Clone
+        + Send
+        + 'static,
+    CN::Future: Send + 'static,
+{
+    tracing::info!("Starting blockchain syncer");
+
+    let BlockChainContextResponse::Context(mut blockchain_ctx) = context_svc
+        .ready()
+        .await?
+        .call(BlockChainContextRequest::GetContext)
+        .await?
+    else {
+        panic!("Blockchain context service returned wrong response!");
+    };
+
+    let mut peer_sync_watch = clearnet_interface.top_sync_stream();
+
+    tracing::debug!("Waiting for new sync info in top sync channel");
+
+    while let Some(top_sync_info) = peer_sync_watch.next().await {
+        tracing::debug!(
+            "New sync info seen, top height: {}, top block hash: {}",
+            top_sync_info.chain_height,
+            hex::encode(top_sync_info.top_hash)
+        );
+
+        // The new info could be from a peer giving us a block, so wait a couple seconds to allow the block to
+        // be added to our blockchain.
+        sleep(Duration::from_secs(2)).await;
+
+        check_update_blockchain_context(&mut context_svc, &mut blockchain_ctx).await?;
+        let raw_blockchain_context = blockchain_ctx.unchecked_blockchain_context();
+
+        if top_sync_info.cumulative_difficulty <= raw_blockchain_context.cumulative_difficulty {
+            tracing::debug!("New peer sync info is not ahead, nothing to do.");
+            continue;
+        }
+
+        tracing::debug!(
+            "We are behind peers claimed cumulative difficulty, starting block downloader"
+        );
+        let mut block_batch_stream =
+            clearnet_interface.block_downloader(our_chain.clone(), block_downloader_config);
+
+        while let Some(batch) = block_batch_stream.next().await {
+            tracing::debug!("Got batch, len: {}", batch.blocks.len());
+            if incoming_block_batch_tx.send(batch).await.is_err() {
+                return Err(SyncerError::IncomingBlockChannelClosed);
+            }
+        }
+    }
+
+    Ok(())
+}
+
+async fn check_update_blockchain_context<C>(
+    context_svc: C,
+    old_context: &mut BlockChainContext,
+) -> Result<(), tower::BoxError>
+where
+    C: Service<
+        BlockChainContextRequest,
+        Response = BlockChainContextResponse,
+        Error = tower::BoxError,
+    >,
+    C::Future: Send + 'static,
+{
+    if old_context.blockchain_context().is_ok() {
+        return Ok(());
+    }
+
+    let BlockChainContextResponse::Context(ctx) = context_svc
+        .oneshot(BlockChainContextRequest::GetContext)
+        .await?
+    else {
+        panic!("Blockchain context service returned wrong response!");
+    };
+
+    *old_context = ctx;
+
+    Ok(())
+}

binaries/cuprated/src/main.rs

@@ -1,8 +1,11 @@
+#![allow(dead_code)]
+
 mod blockchain;
+mod config;
 mod network;
 mod p2p_request_handler;
 mod tx_pool;
 
 fn main() {
-    println!("Hello, world!");
+    todo!();
 }

binaries/cuprated/src/network.rs

@@ -1,26 +0,0 @@
-use bytes::Bytes;
-use dandelion_tower::TxState;
-use futures::Stream;
-
-/// A trait representing the whole P2P network, including all network zones.
-///
-/// [`cuprate_p2p`] provides a per [`NetworkZone`](monero_p2p::NetworkZone) abstraction in [`TODO`], this trait
-/// provides a full abstraction, just exposing a minimal interface for Cuprate to interact with.
-///
-/// It's methods will handle routing to the different [`NetworkZone`](monero_p2p::NetworkZone)s when required.
-///
-/// This is kept generic for testing purposes.
-trait P2PNetwork: Clone {
-    /// An identifier for a node on any [`NetworkZone`](monero_p2p::NetworkZone)
-    type PeerID;
-    /// The block downloader stream.
-    type BlockDownloader: Stream<Item = ()>;
-
-    /// Broadcasts a block to the network.
-    fn broadcast_block(&mut self, block_bytes: Bytes, chain_height: u64);
-
-    /// Broadcasts a transaction to the network.
-    fn broadcast_transaction(&mut self, tx_bytes: Bytes, state: TxState<Self::PeerID>);
-
-    fn block_downloader(&mut self) -> Self::BlockDownloader;
-}

binaries/cuprated/src/p2p_request_handler.rs

@@ -1,7 +0,0 @@
-use cuprate_blockchain::service::DatabaseReadHandle;
-
-pub struct P2PRequestHandler {
-    database: DatabaseReadHandle,
-
-    txpool: (),
-}

binaries/cuprated/src/tx_pool.rs

@@ -1,2 +0,0 @@
-//! # Transaction Pool
-//!

p2p/cuprate-p2p/src/lib.rs

@@ -36,6 +36,7 @@ use client_pool::ClientPoolDropGuard;
 pub use config::P2PConfig;
 use connection_maintainer::MakeConnectionRequest;
 use monero_p2p::services::PeerSyncRequest;
+pub use sync_states::NewSyncInfo;
 
 /// Initializes the P2P [`NetworkInterface`] for a specific [`NetworkZone`].
 ///
@@ -194,7 +195,7 @@ impl<N: NetworkZone> NetworkInterface<N> {
     }
 
     /// Returns a stream which yields the highest seen sync state from a connected peer.
-    pub fn top_sync_stream(&self) -> WatchStream<sync_states::NewSyncInfo> {
+    pub fn top_sync_stream(&self) -> WatchStream<NewSyncInfo> {
         WatchStream::from_changes(self.top_block_watch.clone())
     }