use std::collections::HashMap;
use std::fs;
+use std::ops::Deref;
use std::os::unix::fs::symlink;
use std::sync::Arc;
use std::time::{Duration, SystemTime, UNIX_EPOCH};
+use lightning::log_info;
use lightning::routing::gossip::NetworkGraph;
use lightning::util::logger::Logger;
use crate::config;
use crate::config::cache_path;
-pub(crate) struct Snapshotter<L: Logger> {
- network_graph: Arc<NetworkGraph<Arc<L>>>,
+pub(crate) struct Snapshotter<L: Deref + Clone> where L::Target: Logger {
+ network_graph: Arc<NetworkGraph<L>>,
+ logger: L,
}
-impl<L: Logger> Snapshotter<L> {
- pub fn new(network_graph: Arc<NetworkGraph<Arc<L>>>) -> Self {
- Self { network_graph }
+impl<L: Deref + Clone> Snapshotter<L> where L::Target: Logger {
+ pub fn new(network_graph: Arc<NetworkGraph<L>>, logger: L) -> Self {
+ Self { network_graph, logger }
}
pub(crate) async fn snapshot_gossip(&self) {
- println!("Initiating snapshotting service");
-
- let snapshot_sync_day_factors = [1, 2, 3, 4, 5, 6, 7, 14, 21, u64::MAX];
- let round_day_seconds = config::SNAPSHOT_CALCULATION_INTERVAL as u64;
+ log_info!(self.logger, "Initiating snapshotting service");
+
+ let snapshot_interval = config::snapshot_generation_interval() as u64;
+ let mut snapshot_scopes = vec![];
+ { // double the coefficient until it reaches the maximum (limited) snapshot scope
+ let mut current_scope = snapshot_interval;
+ loop {
+ snapshot_scopes.push(current_scope);
+ if current_scope >= config::MAX_SNAPSHOT_SCOPE as u64 {
+ snapshot_scopes.push(u64::MAX);
+ break;
+ }
- 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";
+ // double the current factor
+ current_scope <<= 1;
+ }
+ }
// 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, 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
-
- // 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 factor in &snapshot_sync_day_factors {
- // basically timestamp - day_seconds * factor
- let timestamp = reference_timestamp.saturating_sub(round_day_seconds.saturating_mul(factor.clone()));
- snapshot_sync_timestamps.push((factor.clone(), timestamp));
- };
+ self.generate_snapshots(config::SYMLINK_GRANULARITY_INTERVAL as u64, snapshot_interval, &snapshot_scopes, &cache_path(), None).await;
- let mut snapshot_filenames_by_day_range: HashMap<u64, String> = HashMap::with_capacity(10);
-
- for (day_range, current_last_sync_timestamp) in &snapshot_sync_timestamps {
- let network_graph_clone = self.network_graph.clone();
- {
- println!("Calculating {}-day snapshot", day_range);
- // calculate the snapshot
- let snapshot = super::serialize_delta(network_graph_clone, current_last_sync_timestamp.clone() as u32).await;
-
- // persist the snapshot and update the symlink
- 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();
- snapshot_filenames_by_day_range.insert(day_range.clone(), snapshot_filename);
- }
- }
+ // constructing the snapshots may have taken a while
+ let current_time = SystemTime::now().duration_since(UNIX_EPOCH).unwrap().as_secs();
+
+ // NOTE: we're waiting until the next multiple of snapshot_interval
+ // however, if the symlink granularity is lower, then during that time, no intermediate
+ // symlinks will be generated. That should be ok, because any timestamps previously
+ // returned would already have generated symlinks, but this does have bug potential
+ let remainder = current_time % snapshot_interval;
+ let time_until_next_generation = snapshot_interval - remainder;
+
+ log_info!(self.logger, "Sleeping until next snapshot capture: {}s", time_until_next_generation);
+ // add in an extra five seconds to assure the rounding down works correctly
+ let sleep = tokio::time::sleep(Duration::from_secs(time_until_next_generation + 5));
+ sleep.await;
+ }
+ }
+
+ pub(crate) async fn generate_snapshots(&self, granularity_interval: u64, snapshot_interval: u64, snapshot_scopes: &[u64], cache_path: &str, max_symlink_count: Option<u64>) {
+ 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<u64, String> = HashMap::with_capacity(10);
+
+ for (current_scope, current_last_sync_timestamp) in &snapshot_sync_timestamps {
+ let network_graph_clone = self.network_graph.clone();
{
- // 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);
- println!("Symlinking dummy: {} -> {}", dummy_symlink_path, relative_dummy_snapshot_path);
- symlink(&relative_dummy_snapshot_path, &dummy_symlink_path).unwrap();
+ 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);
}
+ }
- for i in 0..10_001u64 {
- // let's create non-dummy-symlinks
-
- // first, determine which snapshot range should be referenced
- let referenced_day_range = if i == 0 {
- // special-case 0 to always refer to a full/initial sync
- u64::MAX
- } else {
- // find min(x) in snapshot_sync_day_factors where x >= i
- snapshot_sync_day_factors.iter().find(|x| {
- x >= &&i
- }).unwrap().clone()
- };
-
- let snapshot_filename = snapshot_filenames_by_day_range.get(&referenced_day_range).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(round_day_seconds.saturating_mul(i))
- };
- let symlink_path = format!("{}/{}.bin", pending_symlink_directory, canonical_last_sync_timestamp);
-
- println!("Symlinking: {} -> {} ({} -> {}", i, referenced_day_range, symlink_path, relative_snapshot_path);
- symlink(&relative_snapshot_path, &symlink_path).unwrap();
- }
+ {
+ // 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();
+ }
- 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();
+ // 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);
- 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.");
+ let snapshot_filename = snapshot_filenames_by_scope.get(&referenced_scope).unwrap();
+ let relative_snapshot_path = format!("{}/{}", relative_symlink_to_snapshot_path, snapshot_filename);
- // 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;
+ 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);
- println!("Sleeping until next snapshot capture: {}s", time_until_next_day);
- // add in an extra five seconds to assure the rounding down works correctly
- let sleep = tokio::time::sleep(Duration::from_secs(time_until_next_day + 5));
- sleep.await;
+ 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 {
projects / rapid-gossip-sync-server / blobdiff