From 6adbadea5439c37b6a76125e421a34f86daf6eee Mon Sep 17 00:00:00 2001 From: Arik Sosman Date: Mon, 22 Aug 2022 16:42:20 -0700 Subject: [PATCH] Reference canonical timestamps when generating snapshots. --- src/snapshot.rs | 19 +++++++++---------- 1 file changed, 9 insertions(+), 10 deletions(-) diff --git a/src/snapshot.rs b/src/snapshot.rs index dc67850..dbfbc4d 100644 --- a/src/snapshot.rs +++ b/src/snapshot.rs @@ -32,9 +32,9 @@ impl Snapshotter { // this is gonna be a never-ending background job loop { // 1. get the current timestamp - let timestamp_seen = SystemTime::now().duration_since(UNIX_EPOCH).unwrap().as_secs(); - let filename_timestamp = Self::round_down_to_nearest_multiple(timestamp_seen, round_day_seconds); - println!("Capturing snapshots at {} for: {}", timestamp_seen, filename_timestamp); + let snapshot_generation_timestamp = SystemTime::now().duration_since(UNIX_EPOCH).unwrap().as_secs(); + let reference_timestamp = Self::round_down_to_nearest_multiple(snapshot_generation_timestamp, round_day_seconds); + println!("Capturing snapshots at {} for: {}", snapshot_generation_timestamp, reference_timestamp); // 2. sleep until the next round 24 hours // 3. refresh all snapshots @@ -51,8 +51,6 @@ impl Snapshotter { // 6 (daily) + 3 (weekly) + 1 (total) = 10 cached snapshots // The snapshots, unlike dynamic updates, should account for all intermediate // channel updates - // - // purge and recreate the pending directories if fs::metadata(&pending_snapshot_directory).is_ok(){ @@ -67,7 +65,7 @@ impl Snapshotter { let mut snapshot_sync_timestamps: Vec<(u64, u64)> = Vec::new(); for factor in &snapshot_sync_day_factors { // basically timestamp - day_seconds * factor - let timestamp = timestamp_seen.saturating_sub(round_day_seconds.saturating_mul(factor.clone())); + let timestamp = reference_timestamp.saturating_sub(round_day_seconds.saturating_mul(factor.clone())); snapshot_sync_timestamps.push((factor.clone(), timestamp)); }; @@ -81,7 +79,7 @@ impl Snapshotter { let snapshot = super::serialize_delta(network_graph_clone, current_last_sync_timestamp.clone() as u32, true).await; // persist the snapshot and update the symlink - let snapshot_filename = format!("snapshot__calculated-at:{}__range:{}-days__previous-sync:{}.lngossip", filename_timestamp, day_range, current_last_sync_timestamp); + let snapshot_filename = format!("snapshot__calculated-at:{}__range:{}-days__previous-sync:{}.lngossip", reference_timestamp, day_range, current_last_sync_timestamp); let snapshot_path = format!("{}/{}", pending_snapshot_directory, snapshot_filename); println!("Persisting {}-day snapshot: {} ({} messages, {} announcements, {} updates ({} full, {} incremental))", day_range, snapshot_filename, snapshot.message_count, snapshot.announcement_count, snapshot.update_count, snapshot.update_count_full, snapshot.update_count_incremental); fs::write(&snapshot_path, snapshot.data).unwrap(); @@ -110,8 +108,7 @@ impl Snapshotter { // special-case 0 to always refer to a full/initial sync 0 } else { - let simulated_last_sync_timestamp = timestamp_seen.saturating_sub(round_day_seconds.saturating_mul(i)); - Self::round_down_to_nearest_multiple(simulated_last_sync_timestamp, round_day_seconds) + reference_timestamp.saturating_sub(round_day_seconds.saturating_mul(i)) }; let symlink_path = format!("{}/{}.bin", pending_symlink_directory, canonical_last_sync_timestamp); @@ -128,7 +125,9 @@ impl Snapshotter { fs::rename(&pending_snapshot_directory, &finalized_snapshot_directory).expect("Failed to finalize snapshot directory."); fs::rename(&pending_symlink_directory, &finalized_symlink_directory).expect("Failed to finalize symlink directory."); - let remainder = timestamp_seen % round_day_seconds; + // constructing the snapshots may have taken a while + let current_time = SystemTime::now().duration_since(UNIX_EPOCH).unwrap().as_secs(); + let remainder = current_time % round_day_seconds; let time_until_next_day = round_day_seconds - remainder; println!("Sleeping until next snapshot capture: {}s", time_until_next_day); -- 2.39.5