sc-informant: Print full hash when debug logging is enabled (#7554)

When debugging stuff, it is useful to see the full hashes and not only
the "short form". This makes it easier to read logs and follow blocks.

---------

Co-authored-by: cmd[bot] <41898282+github-actions[bot]@users.noreply.github.com>

prdoc/pr_7554.prdoc

+title: 'sc-informant: Print full hash when debug logging is enabled'
+doc:
+- audience: Node Dev
+  description: |-
+    When debugging stuff, it is useful to see the full hashes and not only the "short form". This makes it easier to read logs and follow blocks.
+crates:
+- name: sc-informant
+  bump: patch

substrate/client/informant/src/display.rs

@@ -24,6 +24,8 @@ use sc_network_sync::{SyncState, SyncStatus, WarpSyncPhase, WarpSyncProgress};
 use sp_runtime::traits::{Block as BlockT, CheckedDiv, NumberFor, Saturating, Zero};
 use std::{fmt, time::Instant};
 
+use crate::PrintFullHashOnDebugLogging;
+
 /// State of the informant display system.
 ///
 /// This is the system that handles the line that gets regularly printed and that looks something
@@ -138,9 +140,9 @@ impl<B: BlockT> InformantDisplay<B> {
 			target,
 			style(num_connected_peers).white().bold(),
 			style(best_number).white().bold(),
-			best_hash,
+			PrintFullHashOnDebugLogging(&best_hash),
 			style(finalized_number).white().bold(),
-			info.chain.finalized_hash,
+			PrintFullHashOnDebugLogging(&info.chain.finalized_hash),
 			style(TransferRateFormat(avg_bytes_per_sec_inbound)).green(),
 			style(TransferRateFormat(avg_bytes_per_sec_outbound)).red(),
 		)

substrate/client/informant/src/lib.rs

@@ -21,13 +21,18 @@
 use console::style;
 use futures::prelude::*;
 use futures_timer::Delay;
-use log::{debug, info, trace};
+use log::{debug, info, log_enabled, trace};
 use sc_client_api::{BlockchainEvents, UsageProvider};
 use sc_network::NetworkStatusProvider;
 use sc_network_sync::{SyncStatusProvider, SyncingService};
 use sp_blockchain::HeaderMetadata;
 use sp_runtime::traits::{Block as BlockT, Header};
-use std::{collections::VecDeque, fmt::Display, sync::Arc, time::Duration};
+use std::{
+	collections::VecDeque,
+	fmt::{Debug, Display},
+	sync::Arc,
+	time::Duration,
+};
 
 mod display;
 
@@ -78,7 +83,20 @@ where
 	};
 }
 
-fn display_block_import<B: BlockT, C>(client: Arc<C>) -> impl Future<Output = ()>
+/// Print the full hash when debug logging is enabled.
+struct PrintFullHashOnDebugLogging<'a, H>(&'a H);
+
+impl<H: Debug + Display> Display for PrintFullHashOnDebugLogging<'_, H> {
+	fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+		if log_enabled!(log::Level::Debug) {
+			Debug::fmt(&self.0, f)
+		} else {
+			Display::fmt(&self.0, f)
+		}
+	}
+}
+
+async fn display_block_import<B: BlockT, C>(client: Arc<C>)
 where
 	C: UsageProvider<B> + HeaderMetadata<B> + BlockchainEvents<B>,
 	<C as HeaderMetadata<B>>::Error: Display,
@@ -91,8 +109,9 @@ where
 	// Hashes of the last blocks we have seen at import.
 	let mut last_blocks = VecDeque::new();
 	let max_blocks_to_track = 100;
+	let mut notifications = client.import_notification_stream();
 
-	client.import_notification_stream().for_each(move |n| {
+	while let Some(n) = notifications.next().await {
 		// detect and log reorganizations.
 		if let Some((ref last_num, ref last_hash)) = last_best {
 			if n.header.parent_hash() != last_hash && n.is_new_best {
@@ -103,9 +122,9 @@ where
 					Ok(ref ancestor) if ancestor.hash != *last_hash => info!(
 						"♻️  Reorg on #{},{} to #{},{}, common ancestor #{},{}",
 						style(last_num).red().bold(),
-						last_hash,
+						PrintFullHashOnDebugLogging(&last_hash),
 						style(n.header.number()).green().bold(),
-						n.hash,
+						PrintFullHashOnDebugLogging(&n.hash),
 						style(ancestor.number).white().bold(),
 						ancestor.hash,
 					),
@@ -133,11 +152,9 @@ where
 				target: "substrate",
 				"{best_indicator} Imported #{} ({} → {})",
 				style(n.header.number()).white().bold(),
-				n.header.parent_hash(),
-				n.hash,
+				PrintFullHashOnDebugLogging(n.header.parent_hash()),
+				PrintFullHashOnDebugLogging(&n.hash),
 			);
 		}
-
-		future::ready(())
-	})
+	}
 }