Store v1 and v2 snapshots.

src/snapshot.rs

@@ -92,14 +92,20 @@ impl<L: Deref + Clone> Snapshotter<L> where L::Target: Logger {
 		// channel updates
 
 		// purge and recreate the pending directories
-		if fs::metadata(&pending_snapshot_directory).is_ok() {
-			fs::remove_dir_all(&pending_snapshot_directory).expect("Failed to remove pending snapshot directory.");
-		}
-		if fs::metadata(&pending_symlink_directory).is_ok() {
-			fs::remove_dir_all(&pending_symlink_directory).expect("Failed to remove pending symlink directory.");
+		let suffixes = ["", "/v2"];
+		for suffix in suffixes {
+			let versioned_snapshot_directory = format!("{}{}", pending_snapshot_directory, suffix);
+			let versioned_symlink_directory = format!("{}{}", pending_symlink_directory, suffix);
+
+			if fs::metadata(&versioned_snapshot_directory).is_ok() {
+				fs::remove_dir_all(&versioned_snapshot_directory).expect("Failed to remove pending snapshot directory.");
+			}
+			if fs::metadata(&versioned_symlink_directory).is_ok() {
+				fs::remove_dir_all(&versioned_symlink_directory).expect("Failed to remove pending symlink directory.");
+			}
+			fs::create_dir_all(&versioned_snapshot_directory).expect("Failed to create pending snapshot directory");
+			fs::create_dir_all(&versioned_symlink_directory).expect("Failed to create pending symlink directory");
 		}
-		fs::create_dir_all(&pending_snapshot_directory).expect("Failed to create pending snapshot directory");
-		fs::create_dir_all(&pending_symlink_directory).expect("Failed to create pending symlink directory");
 
 		let mut snapshot_sync_timestamps: Vec<(u64, u64)> = Vec::new();
 		for current_scope in snapshot_scopes {
@@ -115,13 +121,16 @@ impl<L: Deref + Clone> Snapshotter<L> where L::Target: Logger {
 				log_info!(self.logger, "Calculating {}-second snapshot", current_scope);
 				// calculate the snapshot
 				let delta = super::calculate_delta(network_graph_clone.clone(), current_last_sync_timestamp.clone() as u32, Some(reference_timestamp), self.logger.clone()).await;
-				let snapshot = super::serialize_delta(&delta, 1, self.logger.clone());
+				let snapshot_v1 = super::serialize_delta(&delta, 1, self.logger.clone());
+				let snapshot_v2 = super::serialize_delta(&delta, 2, self.logger.clone());
 
 				// persist the snapshot and update the symlink
 				let snapshot_filename = format!("snapshot__calculated-at:{}__range:{}-scope__previous-sync:{}.lngossip", reference_timestamp, current_scope, current_last_sync_timestamp);
-				let snapshot_path = format!("{}/{}", pending_snapshot_directory, snapshot_filename);
-				log_info!(self.logger, "Persisting {}-second snapshot: {} ({} messages, {} announcements, {} updates ({} full, {} incremental))", current_scope, snapshot_filename, snapshot.message_count, snapshot.channel_announcement_count, snapshot.update_count, snapshot.update_count_full, snapshot.update_count_incremental);
-				fs::write(&snapshot_path, snapshot.data).unwrap();
+				let snapshot_path_v1 = format!("{}/{}", pending_snapshot_directory, snapshot_filename);
+				let snapshot_path_v2 = format!("{}/v2/{}", pending_snapshot_directory, snapshot_filename);
+				log_info!(self.logger, "Persisting {}-second snapshot: {} ({} messages, {} announcements, {} updates ({} full, {} incremental))", current_scope, snapshot_filename, snapshot_v1.message_count, snapshot_v1.channel_announcement_count, snapshot_v1.update_count, snapshot_v1.update_count_full, snapshot_v1.update_count_incremental);
+				fs::write(&snapshot_path_v1, snapshot_v1.data).unwrap();
+				fs::write(&snapshot_path_v2, snapshot_v2.data).unwrap();
 				snapshot_filenames_by_scope.insert(current_scope.clone(), snapshot_filename);
 			}
 		}
@@ -176,19 +185,21 @@ impl<L: Deref + Clone> Snapshotter<L> where L::Target: Logger {
 			};
 			log_info!(self.logger, "i: {}, referenced scope: {}", i, referenced_scope);
 
-			let snapshot_filename = snapshot_filenames_by_scope.get(&referenced_scope).unwrap();
-			let relative_snapshot_path = format!("{}/{}", relative_symlink_to_snapshot_path, snapshot_filename);
+			for suffix in suffixes {
+				let snapshot_filename = snapshot_filenames_by_scope.get(&referenced_scope).unwrap();
+				let relative_snapshot_path = format!("{}{}/{}", relative_symlink_to_snapshot_path, suffix, snapshot_filename);
 
-			let canonical_last_sync_timestamp = if i == 0 {
-				// special-case 0 to always refer to a full/initial sync
-				0
-			} else {
-				reference_timestamp.saturating_sub(granularity_interval.saturating_mul(i))
-			};
-			let symlink_path = format!("{}/{}.bin", pending_symlink_directory, canonical_last_sync_timestamp);
+				let canonical_last_sync_timestamp = if i == 0 {
+					// special-case 0 to always refer to a full/initial sync
+					0
+				} else {
+					reference_timestamp.saturating_sub(granularity_interval.saturating_mul(i))
+				};
+				let symlink_path = format!("{}{}/{}.bin", pending_symlink_directory, suffix, canonical_last_sync_timestamp);
 
-			log_info!(self.logger, "Symlinking: {} -> {} ({} -> {}", i, referenced_scope, symlink_path, relative_snapshot_path);
-			symlink(&relative_snapshot_path, &symlink_path).unwrap();
+				log_info!(self.logger, "Symlinking: {} -> {} ({} -> {}", i, referenced_scope, symlink_path, relative_snapshot_path);
+				symlink(&relative_snapshot_path, &symlink_path).unwrap();
+			}
 		}
 
 		let update_time_path = format!("{}/update_time.txt", pending_symlink_directory);