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proxmox-rrd: implement non blocking journal 

Do not block while applying the journal.
This commit is contained in:
Dietmar Maurer 2021-10-15 12:26:33 +02:00
parent a291ab59ba
commit 0ca41155b2
2 changed files with 320 additions and 115 deletions
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1
proxmox-rrd/Cargo.toml
View File

@ -11,6 +11,7 @@ proxmox-router = "1.1"
[dependencies]
anyhow = "1.0"
bitflags = "1.2.1"
crossbeam-channel = "0.5"
log = "0.4"
nix = "0.19.1"
serde = { version = "1.0", features = ["derive"] }

434
proxmox-rrd/src/cache.rs
View File

@ -1,12 +1,13 @@
use std::fs::File;
use std::path::{Path, PathBuf};
use std::collections::HashMap;
use std::sync::RwLock;
use std::sync::{Arc, RwLock};
use std::io::Write;
use std::io::{BufRead, BufReader};
use std::os::unix::io::AsRawFd;
use std::time::SystemTime;
use std::ffi::OsStr;
use std::thread::spawn;
use crossbeam_channel::{bounded, Receiver, TryRecvError};
use anyhow::{format_err, bail, Error};
use nix::fcntl::OFlag;
@ -21,23 +22,37 @@ const RRD_JOURNAL_NAME: &str = "rrd.journal";
/// This cache is designed to run as single instance (no concurrent
/// access from other processes).
pub struct RRDCache {
config: Arc<CacheConfig>,
state: Arc<RwLock<JournalState>>,
rrd_map: Arc<RwLock<RRDMap>>,
}
struct CacheConfig {
apply_interval: f64,
basedir: PathBuf,
file_options: CreateOptions,
state: RwLock<JournalState>,
rrd_map: RwLock<RRDMap>,
dir_options: CreateOptions,
}
struct RRDMap {
basedir: PathBuf,
file_options: CreateOptions,
dir_options: CreateOptions,
config: Arc<CacheConfig>,
map: HashMap<String, RRD>,
load_rrd_cb: fn(path: &Path, rel_path: &str, dst: DST) -> RRD,
}
impl RRDMap {
fn new(
config: Arc<CacheConfig>,
load_rrd_cb: fn(path: &Path, rel_path: &str, dst: DST) -> RRD,
) -> Self {
Self {
config,
map: HashMap::new(),
load_rrd_cb,
}
}
fn update(
&mut self,
rel_path: &str,
@ -51,9 +66,13 @@ impl RRDMap {
rrd.update(time, value);
}
} else {
let mut path = self.basedir.clone();
let mut path = self.config.basedir.clone();
path.push(rel_path);
create_path(path.parent().unwrap(), Some(self.dir_options.clone()), Some(self.dir_options.clone()))?;
create_path(
path.parent().unwrap(),
Some(self.config.dir_options.clone()),
Some(self.config.dir_options.clone()),
)?;
let mut rrd = (self.load_rrd_cb)(&path, rel_path, dst);
@ -72,10 +91,10 @@ impl RRDMap {
for (rel_path, rrd) in self.map.iter() {
rrd_file_count += 1;
let mut path = self.basedir.clone();
let mut path = self.config.basedir.clone();
path.push(&rel_path);
if let Err(err) = rrd.save(&path, self.file_options.clone()) {
if let Err(err) = rrd.save(&path, self.config.file_options.clone()) {
errors += 1;
log::error!("unable to save {:?}: {}", path, err);
}
@ -106,9 +125,11 @@ impl RRDMap {
// shared state behind RwLock
struct JournalState {
config: Arc<CacheConfig>,
journal: File,
last_journal_flush: f64,
journal_applied: bool,
apply_thread_result: Option<Receiver<Result<(), String>>>,
}
struct JournalEntry {
@ -118,6 +139,98 @@ struct JournalEntry {
rel_path: String,
}
impl JournalState {
fn new(config: Arc<CacheConfig>) -> Result<Self, Error> {
let journal = JournalState::open_journal_writer(&config)?;
Ok(Self {
config,
journal,
last_journal_flush: 0.0,
journal_applied: false,
apply_thread_result: None,
})
}
fn open_journal_reader(&self) -> Result<BufReader<File>, Error> {
// fixme : dup self.journal instead??
let mut journal_path = self.config.basedir.clone();
journal_path.push(RRD_JOURNAL_NAME);
let flags = OFlag::O_CLOEXEC|OFlag::O_RDONLY;
let journal = atomic_open_or_create_file(
&journal_path,
flags,
&[],
self.config.file_options.clone(),
)?;
Ok(BufReader::new(journal))
}
fn open_journal_writer(config: &CacheConfig) -> Result<File, Error> {
let mut journal_path = config.basedir.clone();
journal_path.push(RRD_JOURNAL_NAME);
let flags = OFlag::O_CLOEXEC|OFlag::O_WRONLY|OFlag::O_APPEND;
let journal = atomic_open_or_create_file(
&journal_path,
flags,
&[],
config.file_options.clone(),
)?;
Ok(journal)
}
fn rotate_journal(&mut self) -> Result<(), Error> {
let mut journal_path = self.config.basedir.clone();
journal_path.push(RRD_JOURNAL_NAME);
let mut new_name = journal_path.clone();
let now = proxmox_time::epoch_i64();
new_name.set_extension(format!("journal-{:08x}", now));
std::fs::rename(journal_path, new_name)?;
self.journal = Self::open_journal_writer(&self.config)?;
Ok(())
}
fn remove_old_journals(&self) -> Result<(), Error> {
let journal_list = self.list_old_journals()?;
for (_time, _filename, path) in journal_list {
std::fs::remove_file(path)?;
}
Ok(())
}
fn list_old_journals(&self) -> Result<Vec<(u64, String, PathBuf)>, Error> {
let mut list = Vec::new();
for entry in std::fs::read_dir(&self.config.basedir)? {
let entry = entry?;
let path = entry.path();
if path.is_file() {
if let Some(stem) = path.file_stem() {
if stem != OsStr::new("rrd") { continue; }
if let Some(extension) = path.extension() {
if let Some(extension) = extension.to_str() {
if let Some(rest) = extension.strip_prefix("journal-") {
if let Ok(time) = u64::from_str_radix(rest, 16) {
list.push((time, format!("rrd.{}", extension), path.to_owned()));
}
}
}
}
}
}
}
list.sort_unstable_by_key(|t| t.0);
Ok(list)
}
}
impl RRDCache {
/// Creates a new instance
@ -149,33 +262,21 @@ impl RRDCache {
create_path(&basedir, Some(dir_options.clone()), Some(dir_options.clone()))
.map_err(|err: Error| format_err!("unable to create rrdb stat dir - {}", err))?;
let mut journal_path = basedir.clone();
journal_path.push(RRD_JOURNAL_NAME);
let flags = OFlag::O_CLOEXEC|OFlag::O_WRONLY|OFlag::O_APPEND;
let journal = atomic_open_or_create_file(&journal_path, flags, &[], file_options.clone())?;
let state = JournalState {
journal,
last_journal_flush: 0.0,
journal_applied: false,
};
let rrd_map = RRDMap {
let config = Arc::new(CacheConfig {
basedir: basedir.clone(),
file_options: file_options.clone(),
dir_options: dir_options,
map: HashMap::new(),
load_rrd_cb,
};
apply_interval,
});
let state = JournalState::new(Arc::clone(&config))?;
let rrd_map = RRDMap::new(Arc::clone(&config), load_rrd_cb);
Ok(Self {
basedir,
file_options,
apply_interval,
state: RwLock::new(state),
rrd_map: RwLock::new(rrd_map),
})
config: Arc::clone(&config),
state: Arc::new(RwLock::new(state)),
rrd_map: Arc::new(RwLock::new(rrd_map)),
})
}
/// Create a new RRD as used by the proxmox backup server
@ -243,102 +344,64 @@ impl RRDCache {
}
fn append_journal_entry(
state: &mut JournalState,
&self,
time: f64,
value: f64,
dst: DST,
rel_path: &str,
) -> Result<(), Error> {
let mut state = self.state.write().unwrap(); // block other writers
let journal_entry = format!("{}:{}:{}:{}\n", time, value, dst as u8, rel_path);
state.journal.write_all(journal_entry.as_bytes())?;
Ok(())
}
/// Apply and commit the journal. Should be used at server startup.
pub fn apply_journal(&self) -> Result<(), Error> {
let mut state = self.state.write().unwrap(); // block writers
self.apply_and_commit_journal_locked(&mut state)
}
pub fn apply_journal(&self) -> Result<bool, Error> {
let state = Arc::clone(&self.state);
let rrd_map = Arc::clone(&self.rrd_map);
fn apply_and_commit_journal_locked(&self, state: &mut JournalState) -> Result<(), Error> {
let mut state_guard = self.state.write().unwrap();
let journal_applied = state_guard.journal_applied;
let now = proxmox_time::epoch_f64();
let wants_commit = (now - state_guard.last_journal_flush) > self.config.apply_interval;
state.last_journal_flush = proxmox_time::epoch_f64();
if journal_applied && !wants_commit { return Ok(journal_applied); }
if !state.journal_applied {
let start_time = SystemTime::now();
log::debug!("applying rrd journal");
match self.apply_journal_locked(state) {
Ok(entries) => {
let elapsed = start_time.elapsed()?.as_secs_f64();
log::info!("applied rrd journal ({} entries in {:.3} seconds)", entries, elapsed);
if let Some(ref recv) = state_guard.apply_thread_result {
match recv.try_recv() {
Ok(Ok(())) => {
// finished without errors, OK
}
Ok(Err(err)) => {
// finished with errors, log them
log::error!("{}", err);
}
Err(TryRecvError::Empty) => {
// still running
return Ok(journal_applied);
}
Err(TryRecvError::Disconnected) => {
// crashed, start again
log::error!("apply journal thread crashed - try again");
}
Err(err) => bail!("apply rrd journal failed - {}", err),
}
}
let start_time = SystemTime::now();
log::debug!("commit rrd journal");
state_guard.last_journal_flush = proxmox_time::epoch_f64();
match self.commit_journal_locked(state) {
Ok(rrd_file_count) => {
let elapsed = start_time.elapsed()?.as_secs_f64();
log::info!("rrd journal successfully committed ({} files in {:.3} seconds)",
rrd_file_count, elapsed);
}
Err(err) => bail!("rrd journal commit failed: {}", err),
}
let (sender, receiver) = bounded(1);
state_guard.apply_thread_result = Some(receiver);
Ok(())
spawn(move || {
let result = apply_and_commit_journal_thread(state, rrd_map, journal_applied)
.map_err(|err| err.to_string());
sender.send(result).unwrap();
});
Ok(journal_applied)
}
fn apply_journal_locked(&self, state: &mut JournalState) -> Result<usize, Error> {
let mut journal_path = self.basedir.clone();
journal_path.push(RRD_JOURNAL_NAME);
let flags = OFlag::O_CLOEXEC|OFlag::O_RDONLY;
let journal = atomic_open_or_create_file(&journal_path, flags, &[], self.file_options.clone())?;
let mut journal = BufReader::new(journal);
// fixme: apply blocked to avoid too many calls to self.rrd_map.write() ??
let mut linenr = 0;
loop {
linenr += 1;
let mut line = String::new();
let len = journal.read_line(&mut line)?;
if len == 0 { break; }
let entry = match Self::parse_journal_line(&line) {
Ok(entry) => entry,
Err(err) => {
log::warn!("unable to parse rrd journal line {} (skip) - {}", linenr, err);
continue; // skip unparsable lines
}
};
self.rrd_map.write().unwrap().update(&entry.rel_path, entry.time, entry.value, entry.dst, true)?;
}
// We need to apply the journal only once, because further updates
// are always directly applied.
state.journal_applied = true;
Ok(linenr)
}
fn commit_journal_locked(&self, state: &mut JournalState) -> Result<usize, Error> {
// save all RRDs - we only need a read lock here
let rrd_file_count = self.rrd_map.read().unwrap().flush_rrd_files()?;
// if everything went ok, commit the journal
nix::unistd::ftruncate(state.journal.as_raw_fd(), 0)
.map_err(|err| format_err!("unable to truncate journal - {}", err))?;
Ok(rrd_file_count)
}
/// Update data in RAM and write file back to disk (journal)
pub fn update_value(
@ -349,16 +412,14 @@ impl RRDCache {
dst: DST,
) -> Result<(), Error> {
let mut state = self.state.write().unwrap(); // block other writers
let journal_applied = self.apply_journal()?;
if !state.journal_applied || (time - state.last_journal_flush) > self.apply_interval {
self.apply_and_commit_journal_locked(&mut state)?;
self.append_journal_entry(time, value, dst, rel_path)?;
if journal_applied {
self.rrd_map.write().unwrap().update(rel_path, time, value, dst, false)?;
}
Self::append_journal_entry(&mut state, time, value, dst, rel_path)?;
self.rrd_map.write().unwrap().update(rel_path, time, value, dst, false)?;
Ok(())
}
@ -380,3 +441,146 @@ impl RRDCache {
.extract_cached_data(base, name, cf, resolution, start, end)
}
}
fn apply_and_commit_journal_thread(
state: Arc<RwLock<JournalState>>,
rrd_map: Arc<RwLock<RRDMap>>,
commit_only: bool,
) -> Result<(), Error> {
if commit_only {
state.write().unwrap().rotate_journal()?; // start new journal, keep old one
} else {
let start_time = SystemTime::now();
log::debug!("applying rrd journal");
match apply_journal_impl(Arc::clone(&state), Arc::clone(&rrd_map)) {
Ok(entries) => {
let elapsed = start_time.elapsed().unwrap().as_secs_f64();
log::info!("applied rrd journal ({} entries in {:.3} seconds)", entries, elapsed);
}
Err(err) => bail!("apply rrd journal failed - {}", err),
}
}
let start_time = SystemTime::now();
log::debug!("commit rrd journal");
match commit_journal_impl(state, rrd_map) {
Ok(rrd_file_count) => {
let elapsed = start_time.elapsed().unwrap().as_secs_f64();
log::info!("rrd journal successfully committed ({} files in {:.3} seconds)",
rrd_file_count, elapsed);
}
Err(err) => bail!("rrd journal commit failed: {}", err),
}
Ok(())
}
fn apply_journal_lines(
state: Arc<RwLock<JournalState>>,
rrd_map: Arc<RwLock<RRDMap>>,
journal_name: &str, // used for logging
reader: &mut BufReader<File>,
lock_read_line: bool,
) -> Result<usize, Error> {
let mut linenr = 0;
loop {
linenr += 1;
let mut line = String::new();
let len = if lock_read_line {
let _lock = state.read().unwrap(); // make sure we read entire lines
reader.read_line(&mut line)?
} else {
reader.read_line(&mut line)?
};
if len == 0 { break; }
let entry = match RRDCache::parse_journal_line(&line) {
Ok(entry) => entry,
Err(err) => {
log::warn!(
"unable to parse rrd journal '{}' line {} (skip) - {}",
journal_name, linenr, err,
);
continue; // skip unparsable lines
}
};
rrd_map.write().unwrap().update(&entry.rel_path, entry.time, entry.value, entry.dst, true)?;
}
Ok(linenr)
}
fn apply_journal_impl(
state: Arc<RwLock<JournalState>>,
rrd_map: Arc<RwLock<RRDMap>>,
) -> Result<usize, Error> {
let mut lines = 0;
// Apply old journals first
let journal_list = state.read().unwrap().list_old_journals()?;
for (_time, filename, path) in journal_list {
log::info!("apply old journal log {}", filename);
let file = std::fs::OpenOptions::new().read(true).open(path)?;
let mut reader = BufReader::new(file);
lines += apply_journal_lines(
Arc::clone(&state),
Arc::clone(&rrd_map),
&filename,
&mut reader,
false,
)?;
}
let mut journal = state.read().unwrap().open_journal_reader()?;
lines += apply_journal_lines(
Arc::clone(&state),
Arc::clone(&rrd_map),
"rrd.journal",
&mut journal,
true,
)?;
{
let mut state_guard = state.write().unwrap(); // block other writers
lines += apply_journal_lines(
Arc::clone(&state),
Arc::clone(&rrd_map),
"rrd.journal",
&mut journal,
false,
)?;
state_guard.rotate_journal()?; // start new journal, keep old one
// We need to apply the journal only once, because further updates
// are always directly applied.
state_guard.journal_applied = true;
}
Ok(lines)
}
fn commit_journal_impl(
state: Arc<RwLock<JournalState>>,
rrd_map: Arc<RwLock<RRDMap>>,
) -> Result<usize, Error> {
// save all RRDs - we only need a read lock here
let rrd_file_count = rrd_map.read().unwrap().flush_rrd_files()?;
// if everything went ok, remove the old journal files
state.write().unwrap().remove_old_journals()?;
Ok(rrd_file_count)
}