mirror of https://github.com/mastodon/flodgatt
149 lines
5.4 KiB
Rust
149 lines
5.4 KiB
Rust
//! Receives data from Redis, sorts it by `ClientAgent`, and stores it until
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//! polled by the correct `ClientAgent`. Also manages sububscriptions and
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//! unsubscriptions to/from Redis.
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mod err;
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pub use err::Error;
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use super::Event;
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use super::{RedisCmd, RedisConn};
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use crate::config;
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use crate::request::{Subscription, Timeline};
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pub(self) use super::EventErr;
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use futures::Async;
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use hashbrown::{HashMap, HashSet};
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use std::sync::{Arc, Mutex, MutexGuard, PoisonError};
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use std::time::{Duration, Instant};
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use tokio::sync::mpsc::Sender;
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type Result<T> = std::result::Result<T, Error>;
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/// The item that streams from Redis and is polled by the `ClientAgent`
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pub struct Manager {
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redis_connection: RedisConn,
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timelines: HashMap<Timeline, HashMap<u32, Sender<Arc<Event>>>>,
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ping_time: Instant,
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channel_id: u32,
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}
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impl Manager {
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/// Create a new `Manager`, with its own Redis connections (but no active subscriptions).
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pub fn try_from(redis_cfg: &config::Redis) -> Result<Self> {
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Ok(Self {
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redis_connection: RedisConn::new(redis_cfg)?,
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timelines: HashMap::new(),
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ping_time: Instant::now(),
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channel_id: 0,
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})
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}
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pub fn into_arc(self) -> Arc<Mutex<Self>> {
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Arc::new(Mutex::new(self))
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}
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pub fn subscribe(&mut self, subscription: &Subscription, channel: Sender<Arc<Event>>) {
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let (tag, tl) = (subscription.hashtag_name.clone(), subscription.timeline);
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if let (Some(hashtag), Some(id)) = (tag, tl.tag()) {
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self.redis_connection.update_cache(hashtag, id);
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};
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let channels = self.timelines.entry(tl).or_default();
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channels.insert(self.channel_id, channel);
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self.channel_id += 1;
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if channels.len() == 1 {
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self.redis_connection
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.send_cmd(RedisCmd::Subscribe, &tl)
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.unwrap_or_else(|e| log::error!("Could not subscribe to the Redis channel: {}", e));
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};
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}
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pub(crate) fn unsubscribe(&mut self, tl: &Timeline) -> Result<()> {
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self.redis_connection.send_cmd(RedisCmd::Unsubscribe, &tl)?;
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self.timelines.remove(&tl);
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Ok(log::info!("Ended stream for {:?}", tl))
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}
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pub fn poll_broadcast(&mut self) -> Result<()> {
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let mut completed_timelines = HashSet::new();
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let log_send_err = |tl, e| Some(log::error!("cannot send to {:?}: {}", tl, e)).is_some();
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if self.ping_time.elapsed() > Duration::from_secs(30) {
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self.ping_time = Instant::now();
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for (tl, channels) in self.timelines.iter_mut() {
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channels.retain(|_, chan| match chan.try_send(Arc::new(Event::Ping)) {
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Ok(()) => true,
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Err(e) if !e.is_closed() => log_send_err(*tl, e),
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Err(_) => false,
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});
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// NOTE: this takes two cycles to close a connection after the client
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// times out: on the first cycle, this fn sends the Event to the
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// response::Ws thread without any error, but that thread encounters an
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// error sending to the client and ends. On the *second* cycle, this fn
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// gets the error it's waiting on to clean up the connection. This isn't
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// ideal, but is harmless, since the only reason we haven't cleaned up the
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// connection is that no messages are being sent to that client.
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if channels.is_empty() {
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completed_timelines.insert(*tl);
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}
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}
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};
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loop {
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match self.redis_connection.poll_redis() {
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Ok(Async::NotReady) => break,
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Ok(Async::Ready(Some((tl, event)))) => {
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let sendable_event = Arc::new(event);
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let channels = self.timelines.get_mut(&tl).ok_or(Error::InvalidId)?;
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channels.retain(|_, chan| match chan.try_send(sendable_event.clone()) {
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Ok(()) => true,
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Err(e) if !e.is_closed() => log_send_err(tl, e),
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Err(_) => false,
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});
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if channels.is_empty() {
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completed_timelines.insert(tl);
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}
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}
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Ok(Async::Ready(None)) => (), // cmd or msg for other namespace
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Err(err) => log::error!("{}", err), // drop msg, log err, and proceed
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}
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}
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for tl in &mut completed_timelines.iter() {
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self.unsubscribe(tl)?;
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}
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Ok(())
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}
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pub fn recover(poisoned: PoisonError<MutexGuard<Self>>) -> MutexGuard<Self> {
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log::error!("{}", &poisoned);
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poisoned.into_inner()
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}
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pub fn count(&self) -> String {
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format!(
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"Current connections: {}",
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self.timelines.values().map(HashMap::len).sum::<usize>()
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)
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}
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pub fn list(&self) -> String {
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let max_len = self
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.timelines
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.keys()
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.fold(0, |acc, el| acc.max(format!("{:?}:", el).len()));
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self.timelines
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.iter()
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.map(|(tl, channel_map)| {
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let tl_txt = format!("{:?}:", tl);
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format!("{:>1$} {2}\n", tl_txt, max_len, channel_map.len())
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})
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.chain(std::iter::once(
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"\n*may include recently disconnected clients".to_string(),
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))
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.collect()
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}
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}
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