From 0281c0c97a58496004a1edaec1911bab43250ee5 Mon Sep 17 00:00:00 2001 From: Arik Sosman Date: Tue, 17 Oct 2023 13:49:48 -0700 Subject: [PATCH] Extract snapshot generation method. --- src/snapshot.rs | 275 +++++++++++++++++++++++++----------------------- 1 file changed, 142 insertions(+), 133 deletions(-) diff --git a/src/snapshot.rs b/src/snapshot.rs index 2182856..07427a6 100644 --- a/src/snapshot.rs +++ b/src/snapshot.rs @@ -41,141 +41,9 @@ impl Snapshotter where L::Target: Logger { } } - let pending_snapshot_directory = format!("{}/snapshots_pending", cache_path()); - let pending_symlink_directory = format!("{}/symlinks_pending", cache_path()); - let finalized_snapshot_directory = format!("{}/snapshots", cache_path()); - let finalized_symlink_directory = format!("{}/symlinks", cache_path()); - let relative_symlink_to_snapshot_path = "../snapshots"; - // this is gonna be a never-ending background job loop { - // 1. get the current 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, snapshot_interval as u64); - log_info!(self.logger, "Capturing snapshots at {} for: {}", snapshot_generation_timestamp, reference_timestamp); - - // 2. sleep until the next round interval - // 3. refresh all snapshots - - // the stored snapshots should adhere to the following format - // from one day ago - // from two days ago - // … - // from a week ago - // from two weeks ago - // from three weeks ago - // full - // That means that at any given moment, there should only ever be - // 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() { - 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."); - } - 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 { - let timestamp = reference_timestamp.saturating_sub(current_scope.clone()); - snapshot_sync_timestamps.push((current_scope.clone(), timestamp)); - }; - - let mut snapshot_filenames_by_scope: HashMap = HashMap::with_capacity(10); - - for (current_scope, current_last_sync_timestamp) in &snapshot_sync_timestamps { - let network_graph_clone = self.network_graph.clone(); - { - log_info!(self.logger, "Calculating {}-second snapshot", current_scope); - // calculate the snapshot - let snapshot = super::serialize_delta(network_graph_clone, current_last_sync_timestamp.clone() as u32, self.logger.clone()).await; - - // 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.announcement_count, snapshot.update_count, snapshot.update_count_full, snapshot.update_count_incremental); - fs::write(&snapshot_path, snapshot.data).unwrap(); - snapshot_filenames_by_scope.insert(current_scope.clone(), snapshot_filename); - } - } - - { - // create dummy symlink - let dummy_filename = "empty_delta.lngossip"; - let dummy_snapshot = super::serialize_empty_blob(reference_timestamp); - let dummy_snapshot_path = format!("{}/{}", pending_snapshot_directory, dummy_filename); - fs::write(&dummy_snapshot_path, dummy_snapshot).unwrap(); - - let dummy_symlink_path = format!("{}/{}.bin", pending_symlink_directory, reference_timestamp); - let relative_dummy_snapshot_path = format!("{}/{}", relative_symlink_to_snapshot_path, dummy_filename); - log_info!(self.logger, "Symlinking dummy: {} -> {}", dummy_symlink_path, relative_dummy_snapshot_path); - symlink(&relative_dummy_snapshot_path, &dummy_symlink_path).unwrap(); - } - - // Number of intervals since Jan 1, 2022, a few months before RGS server was released. - let symlink_count = (reference_timestamp - 1640995200) / config::SYMLINK_GRANULARITY_INTERVAL as u64; - for i in 0..symlink_count { - // let's create non-dummy-symlinks - - // first, determine which snapshot range should be referenced - let referenced_scope = if i == 0 { - // special-case 0 to always refer to a full/initial sync - u64::MAX - } else { - /* - We have snapshots for 6-day- and 7-day-intervals, but the next interval is - 14 days. So if somebody requests an update with a timestamp that is 10 days old, - there is no longer a snapshot for that specific interval. - - The correct snapshot will be the next highest interval, i. e. for 14 days. - - The `snapshot_sync_day_factors` array is sorted ascendingly, so find() will - return on the first iteration that is at least equal to the requested interval. - - Note, however, that the last value in the array is u64::max, which means that - multiplying it with snapshot_interval will overflow. To avoid that, we use - saturating_mul. - */ - - // find min(x) in snapshot_scopes where i * granularity <= x (the current scope) - snapshot_scopes.iter().find(|current_scope| { - i * config::SYMLINK_GRANULARITY_INTERVAL as u64 <= **current_scope - }).unwrap().clone() - }; - 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); - - 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((config::SYMLINK_GRANULARITY_INTERVAL as u64).saturating_mul(i)) - }; - let symlink_path = format!("{}/{}.bin", pending_symlink_directory, canonical_last_sync_timestamp); - - 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); - let update_time = SystemTime::now().duration_since(UNIX_EPOCH).unwrap().as_secs(); - fs::write(&update_time_path, format!("{}", update_time)).unwrap(); - - if fs::metadata(&finalized_snapshot_directory).is_ok() { - fs::remove_dir_all(&finalized_snapshot_directory).expect("Failed to remove finalized snapshot directory."); - } - if fs::metadata(&finalized_symlink_directory).is_ok() { - fs::remove_dir_all(&finalized_symlink_directory).expect("Failed to remove pending symlink directory."); - } - 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."); + self.generate_snapshots(config::SYMLINK_GRANULARITY_INTERVAL as u64, snapshot_interval, &snapshot_scopes, &cache_path(), None).await; // constructing the snapshots may have taken a while let current_time = SystemTime::now().duration_since(UNIX_EPOCH).unwrap().as_secs(); @@ -194,6 +62,147 @@ impl Snapshotter where L::Target: Logger { } } + pub(crate) async fn generate_snapshots(&self, granularity_interval: u64, snapshot_interval: u64, snapshot_scopes: &[u64], cache_path: &str, max_symlink_count: Option) { + let pending_snapshot_directory = format!("{}/snapshots_pending", cache_path); + let pending_symlink_directory = format!("{}/symlinks_pending", cache_path); + let finalized_snapshot_directory = format!("{}/snapshots", cache_path); + let finalized_symlink_directory = format!("{}/symlinks", cache_path); + let relative_symlink_to_snapshot_path = "../snapshots"; + + // 1. get the current 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, snapshot_interval as u64); + log_info!(self.logger, "Capturing snapshots at {} for: {}", snapshot_generation_timestamp, reference_timestamp); + + // 2. sleep until the next round interval + // 3. refresh all snapshots + + // the stored snapshots should adhere to the following format + // from one day ago + // from two days ago + // … + // from a week ago + // from two weeks ago + // from three weeks ago + // full + // That means that at any given moment, there should only ever be + // 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() { + 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."); + } + 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 { + let timestamp = reference_timestamp.saturating_sub(current_scope.clone()); + snapshot_sync_timestamps.push((current_scope.clone(), timestamp)); + }; + + let mut snapshot_filenames_by_scope: HashMap = HashMap::with_capacity(10); + + for (current_scope, current_last_sync_timestamp) in &snapshot_sync_timestamps { + let network_graph_clone = self.network_graph.clone(); + { + log_info!(self.logger, "Calculating {}-second snapshot", current_scope); + // calculate the snapshot + let snapshot = super::serialize_delta(network_graph_clone, current_last_sync_timestamp.clone() as u32, self.logger.clone()).await; + + // 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.announcement_count, snapshot.update_count, snapshot.update_count_full, snapshot.update_count_incremental); + fs::write(&snapshot_path, snapshot.data).unwrap(); + snapshot_filenames_by_scope.insert(current_scope.clone(), snapshot_filename); + } + } + + { + // create dummy symlink + let dummy_filename = "empty_delta.lngossip"; + let dummy_snapshot = super::serialize_empty_blob(reference_timestamp); + let dummy_snapshot_path = format!("{}/{}", pending_snapshot_directory, dummy_filename); + fs::write(&dummy_snapshot_path, dummy_snapshot).unwrap(); + + let dummy_symlink_path = format!("{}/{}.bin", pending_symlink_directory, reference_timestamp); + let relative_dummy_snapshot_path = format!("{}/{}", relative_symlink_to_snapshot_path, dummy_filename); + log_info!(self.logger, "Symlinking dummy: {} -> {}", dummy_symlink_path, relative_dummy_snapshot_path); + symlink(&relative_dummy_snapshot_path, &dummy_symlink_path).unwrap(); + } + + // Number of intervals since Jan 1, 2022, a few months before RGS server was released. + let mut symlink_count = (reference_timestamp - 1640995200) / granularity_interval; + if let Some(max_symlink_count) = max_symlink_count { + // this is primarily useful for testing + symlink_count = std::cmp::min(symlink_count, max_symlink_count); + }; + + for i in 0..symlink_count { + // let's create non-dummy-symlinks + + // first, determine which snapshot range should be referenced + let referenced_scope = if i == 0 { + // special-case 0 to always refer to a full/initial sync + u64::MAX + } else { + /* + We have snapshots for 6-day- and 7-day-intervals, but the next interval is + 14 days. So if somebody requests an update with a timestamp that is 10 days old, + there is no longer a snapshot for that specific interval. + + The correct snapshot will be the next highest interval, i. e. for 14 days. + + The `snapshot_sync_day_factors` array is sorted ascendingly, so find() will + return on the first iteration that is at least equal to the requested interval. + + Note, however, that the last value in the array is u64::max, which means that + multiplying it with snapshot_interval will overflow. To avoid that, we use + saturating_mul. + */ + + // find min(x) in snapshot_scopes where i * granularity <= x (the current scope) + snapshot_scopes.iter().find(|current_scope| { + i * granularity_interval <= **current_scope + }).unwrap().clone() + }; + 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); + + 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); + + 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); + let update_time = SystemTime::now().duration_since(UNIX_EPOCH).unwrap().as_secs(); + fs::write(&update_time_path, format!("{}", update_time)).unwrap(); + + if fs::metadata(&finalized_snapshot_directory).is_ok() { + fs::remove_dir_all(&finalized_snapshot_directory).expect("Failed to remove finalized snapshot directory."); + } + if fs::metadata(&finalized_symlink_directory).is_ok() { + fs::remove_dir_all(&finalized_symlink_directory).expect("Failed to remove pending symlink directory."); + } + 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."); + } + pub(super) fn round_down_to_nearest_multiple(number: u64, multiple: u64) -> u64 { let round_multiple_delta = number % multiple; number - round_multiple_delta -- 2.39.5