Enable block archival sync (#3579)

* wip - body sync for full archive

* allow chain compaction during sync

* placeholder for logic to ensure archive nodes sync from archive nodes

* body sync from archival peers

* allow chain compaction during sync

* placeholder for logic to ensure archive nodes sync from archive nodes

chain/src/chain.rs

@@ -226,6 +226,11 @@ impl Chain {
 		Ok(chain)
 	}
 
+	/// Are we running with archive_mode enabled?
+	pub fn archive_mode(&self) -> bool {
+		self.archive_mode
+	}
+
 	/// Return our shared header MMR handle.
 	pub fn header_pmmr(&self) -> Arc<RwLock<PMMRHandle<BlockHeader>>> {
 		self.header_pmmr.clone()
@@ -889,6 +894,11 @@ impl Chain {
 	/// If beyond the horizon then we cannot sync via recent full blocks
 	/// and we need a state (txhashset) sync.
 	pub fn check_txhashset_needed(&self, fork_point: &BlockHeader) -> Result<bool, Error> {
+		if self.archive_mode() {
+			debug!("check_txhashset_needed: we are running with archive_mode=true, not needed");
+			return Ok(false);
+		}
+
 		let header_head = self.header_head()?;
 		let horizon = global::cut_through_horizon() as u64;
 		Ok(fork_point.height < header_head.height.saturating_sub(horizon))
@@ -1075,7 +1085,7 @@ impl Chain {
 		header_pmmr: &txhashset::PMMRHandle<BlockHeader>,
 		batch: &store::Batch<'_>,
 	) -> Result<(), Error> {
-		if self.archive_mode {
+		if self.archive_mode() {
 			return Ok(());
 		}
 
@@ -1161,13 +1171,14 @@ impl Chain {
 		}
 
 		// If we are not in archival mode remove historical blocks from the db.
-		if !self.archive_mode {
+		if !self.archive_mode() {
 			self.remove_historical_blocks(&header_pmmr, &batch)?;
 		}
 
 		// Make sure our output_pos index is consistent with the UTXO set.
 		txhashset.init_output_pos_index(&header_pmmr, &batch)?;
 
+		// TODO - Why is this part of chain compaction?
 		// Rebuild our NRD kernel_pos index based on recent kernel history.
 		txhashset.init_recent_kernel_pos_index(&header_pmmr, &batch)?;
 

servers/src/common/adapters.rs

@@ -704,11 +704,6 @@ where
 	}
 
 	fn check_compact(&self) {
-		// Skip compaction if we are syncing.
-		if self.sync_state.is_syncing() {
-			return;
-		}
-
 		// Roll the dice to trigger compaction at 1/COMPACTION_CHECK chance per block,
 		// uses a different thread to avoid blocking the caller thread (likely a peer)
 		let mut rng = thread_rng();

servers/src/grin/sync/body_sync.rs

@@ -14,6 +14,7 @@
 
 use chrono::prelude::{DateTime, Utc};
 use chrono::Duration;
+use p2p::Capabilities;
 use rand::prelude::*;
 use std::cmp;
 use std::sync::Arc;
@@ -71,6 +72,11 @@ impl BodySync {
 		Ok(false)
 	}
 
+	/// Is our local node running in archive_mode?
+	fn archive_mode(&self) -> bool {
+		self.chain.archive_mode()
+	}
+
 	/// Return true if txhashset download is needed (when requested block is under the horizon).
 	/// Otherwise go request some missing blocks and return false.
 	fn body_sync(&mut self) -> Result<bool, chain::Error> {
@@ -85,27 +91,40 @@ impl BodySync {
 			return Ok(true);
 		}
 
-		// Find connected peers with strictly greater difficulty than us.
+		let peers = {
-		let peers_iter = || {
+			// Find connected peers with strictly greater difficulty than us.
-			self.peers
+			let peers_iter = || {
-				.iter()
+				// If we are running with archive mode enabled we only want to sync
-				.with_difficulty(|x| x > head.total_difficulty)
+				// from other archive nodes.
-				.connected()
+				let cap = if self.archive_mode() {
+					Capabilities::BLOCK_HIST
+				} else {
+					Capabilities::UNKNOWN
+				};
+
+				self.peers
+					.iter()
+					.with_capabilities(cap)
+					.with_difficulty(|x| x > head.total_difficulty)
+					.connected()
+			};
+
+			// We prefer outbound peers with greater difficulty.
+			let mut peers: Vec<_> = peers_iter().outbound().into_iter().collect();
+			if peers.is_empty() {
+				debug!("no outbound peers with more work, considering inbound");
+				peers = peers_iter().inbound().into_iter().collect();
+			}
+
+			// If we have no peers (outbound or inbound) then we are done for now.
+			if peers.is_empty() {
+				debug!("no peers (inbound or outbound) with more work");
+				return Ok(false);
+			}
+
+			peers
 		};
 
-		// We prefer outbound peers with greater difficulty.
-		let mut peers: Vec<_> = peers_iter().outbound().into_iter().collect();
-		if peers.is_empty() {
-			debug!("no outbound peers with more work, considering inbound");
-			peers = peers_iter().inbound().into_iter().collect();
-		}
-
-		// If we have no peers (outbound or inbound) then we are done for now.
-		if peers.is_empty() {
-			debug!("no peers (inbound or outbound) with more work");
-			return Ok(false);
-		}
-
 		// if we have 5 peers to sync from then ask for 50 blocks total (peer_count *
 		// 10) max will be 80 if all 8 peers are advertising more work
 		// also if the chain is already saturated with orphans, throttle