lemmy/crates/federate/src/worker.rs

368 lines
14 KiB
Rust

use crate::util::{
get_activity_cached,
get_actor_cached,
get_latest_activity_id,
FederationQueueStateWithDomain,
LEMMY_TEST_FAST_FEDERATION,
WORK_FINISHED_RECHECK_DELAY,
};
use activitypub_federation::{
activity_sending::SendActivityTask,
config::Data,
protocol::context::WithContext,
};
use anyhow::{Context, Result};
use chrono::{DateTime, Days, TimeZone, Utc};
use lemmy_api_common::{context::LemmyContext, federate_retry_sleep_duration};
use lemmy_apub::{activity_lists::SharedInboxActivities, FEDERATION_CONTEXT};
use lemmy_db_schema::{
newtypes::{ActivityId, CommunityId, InstanceId},
source::{
activity::SentActivity,
federation_queue_state::FederationQueueState,
instance::{Instance, InstanceForm},
site::Site,
},
utils::naive_now,
};
use lemmy_db_views_actor::structs::CommunityFollowerView;
use once_cell::sync::Lazy;
use reqwest::Url;
use std::{
collections::{HashMap, HashSet},
ops::{Add, Deref},
time::Duration,
};
use tokio::{sync::mpsc::UnboundedSender, time::sleep};
use tokio_util::sync::CancellationToken;
use tracing::{debug, info, trace, warn};
/// Check whether to save state to db every n sends if there's no failures (during failures state is
/// saved after every attempt). This determines the batch size for loop_batch. After a batch ends
/// and SAVE_STATE_EVERY_TIME has passed, the federation_queue_state is updated in the DB.
static CHECK_SAVE_STATE_EVERY_IT: i64 = 100;
/// Save state to db after this time has passed since the last state (so if the server crashes or is
/// SIGKILLed, less than X seconds of activities are resent)
static SAVE_STATE_EVERY_TIME: Duration = Duration::from_secs(60);
/// interval with which new additions to community_followers are queried.
///
/// The first time some user on an instance follows a specific remote community (or, more precisely:
/// the first time a (followed_community_id, follower_inbox_url) tuple appears), this delay limits
/// the maximum time until the follow actually results in activities from that community id being
/// sent to that inbox url. This delay currently needs to not be too small because the DB load is
/// currently fairly high because of the current structure of storing inboxes for every person, not
/// having a separate list of shared_inboxes, and the architecture of having every instance queue be
/// fully separate. (see https://github.com/LemmyNet/lemmy/issues/3958)
static FOLLOW_ADDITIONS_RECHECK_DELAY: Lazy<chrono::TimeDelta> = Lazy::new(|| {
if *LEMMY_TEST_FAST_FEDERATION {
chrono::TimeDelta::try_seconds(1).expect("TimeDelta out of bounds")
} else {
chrono::TimeDelta::try_minutes(2).expect("TimeDelta out of bounds")
}
});
/// The same as FOLLOW_ADDITIONS_RECHECK_DELAY, but triggering when the last person on an instance
/// unfollows a specific remote community. This is expected to happen pretty rarely and updating it
/// in a timely manner is not too important.
static FOLLOW_REMOVALS_RECHECK_DELAY: Lazy<chrono::TimeDelta> =
Lazy::new(|| chrono::TimeDelta::try_hours(1).expect("TimeDelta out of bounds"));
pub(crate) struct InstanceWorker {
instance: Instance,
// load site lazily because if an instance is first seen due to being on allowlist,
// the corresponding row in `site` may not exist yet since that is only added once
// `fetch_instance_actor_for_object` is called.
// (this should be unlikely to be relevant outside of the federation tests)
site_loaded: bool,
site: Option<Site>,
followed_communities: HashMap<CommunityId, HashSet<Url>>,
stop: CancellationToken,
context: Data<LemmyContext>,
stats_sender: UnboundedSender<FederationQueueStateWithDomain>,
last_full_communities_fetch: DateTime<Utc>,
last_incremental_communities_fetch: DateTime<Utc>,
state: FederationQueueState,
last_state_insert: DateTime<Utc>,
}
impl InstanceWorker {
pub(crate) async fn init_and_loop(
instance: Instance,
context: Data<LemmyContext>,
stop: CancellationToken,
stats_sender: UnboundedSender<FederationQueueStateWithDomain>,
) -> Result<(), anyhow::Error> {
let mut pool = context.pool();
let state = FederationQueueState::load(&mut pool, instance.id).await?;
let mut worker = InstanceWorker {
instance,
site_loaded: false,
site: None,
followed_communities: HashMap::new(),
stop,
context,
stats_sender,
last_full_communities_fetch: Utc.timestamp_nanos(0),
last_incremental_communities_fetch: Utc.timestamp_nanos(0),
state,
last_state_insert: Utc.timestamp_nanos(0),
};
worker.loop_until_stopped().await
}
/// loop fetch new activities from db and send them to the inboxes of the given instances
/// this worker only returns if (a) there is an internal error or (b) the cancellation token is
/// cancelled (graceful exit)
pub(crate) async fn loop_until_stopped(&mut self) -> Result<(), anyhow::Error> {
debug!("Starting federation worker for {}", self.instance.domain);
let save_state_every = chrono::Duration::from_std(SAVE_STATE_EVERY_TIME).expect("not negative");
self.update_communities().await?;
self.initial_fail_sleep().await?;
while !self.stop.is_cancelled() {
self.loop_batch().await?;
if self.stop.is_cancelled() {
break;
}
if (Utc::now() - self.last_state_insert) > save_state_every {
self.save_and_send_state().await?;
}
self.update_communities().await?;
}
// final update of state in db
self.save_and_send_state().await?;
Ok(())
}
async fn initial_fail_sleep(&mut self) -> Result<()> {
// before starting queue, sleep remaining duration if last request failed
if self.state.fail_count > 0 {
let last_retry = self
.state
.last_retry
.context("impossible: if fail count set last retry also set")?;
let elapsed = (Utc::now() - last_retry).to_std()?;
let required = federate_retry_sleep_duration(self.state.fail_count);
if elapsed >= required {
return Ok(());
}
let remaining = required - elapsed;
tokio::select! {
() = sleep(remaining) => {},
() = self.stop.cancelled() => {}
}
}
Ok(())
}
/// send out a batch of CHECK_SAVE_STATE_EVERY_IT activities
async fn loop_batch(&mut self) -> Result<()> {
let latest_id = get_latest_activity_id(&mut self.context.pool()).await?;
let mut id = if let Some(id) = self.state.last_successful_id {
id
} else {
// this is the initial creation (instance first seen) of the federation queue for this
// instance
// skip all past activities:
self.state.last_successful_id = Some(latest_id);
// save here to ensure it's not read as 0 again later if no activities have happened
self.save_and_send_state().await?;
latest_id
};
if id >= latest_id {
if id > latest_id {
tracing::error!(
"{}: last successful id {} is higher than latest id {} in database (did the db get cleared?)",
self.instance.domain,
id.0,
latest_id.0
);
}
// no more work to be done, wait before rechecking
tokio::select! {
() = sleep(*WORK_FINISHED_RECHECK_DELAY) => {},
() = self.stop.cancelled() => {}
}
return Ok(());
}
let mut processed_activities = 0;
while id < latest_id
&& processed_activities < CHECK_SAVE_STATE_EVERY_IT
&& !self.stop.is_cancelled()
{
id = ActivityId(id.0 + 1);
processed_activities += 1;
let Some(ele) = get_activity_cached(&mut self.context.pool(), id)
.await
.context("failed reading activity from db")?
else {
debug!("{}: {:?} does not exist", self.instance.domain, id);
self.state.last_successful_id = Some(id);
continue;
};
if let Err(e) = self.send_retry_loop(&ele.0, &ele.1).await {
warn!(
"sending {} errored internally, skipping activity: {:?}",
ele.0.ap_id, e
);
}
if self.stop.is_cancelled() {
return Ok(());
}
// send success!
self.state.last_successful_id = Some(id);
self.state.last_successful_published_time = Some(ele.0.published);
self.state.fail_count = 0;
}
Ok(())
}
// this function will return successfully when (a) send succeeded or (b) worker cancelled
// and will return an error if an internal error occurred (send errors cause an infinite loop)
async fn send_retry_loop(
&mut self,
activity: &SentActivity,
object: &SharedInboxActivities,
) -> Result<()> {
let inbox_urls = self
.get_inbox_urls(activity)
.await
.context("failed figuring out inbox urls")?;
if inbox_urls.is_empty() {
trace!("{}: {:?} no inboxes", self.instance.domain, activity.id);
self.state.last_successful_id = Some(activity.id);
self.state.last_successful_published_time = Some(activity.published);
return Ok(());
}
let Some(actor_apub_id) = &activity.actor_apub_id else {
return Ok(()); // activity was inserted before persistent queue was activated
};
let actor = get_actor_cached(&mut self.context.pool(), activity.actor_type, actor_apub_id)
.await
.context("failed getting actor instance (was it marked deleted / removed?)")?;
let object = WithContext::new(object.clone(), FEDERATION_CONTEXT.deref().clone());
let inbox_urls = inbox_urls.into_iter().collect();
let requests =
SendActivityTask::prepare(&object, actor.as_ref(), inbox_urls, &self.context).await?;
for task in requests {
// usually only one due to shared inbox
trace!("sending out {}", task);
while let Err(e) = task.sign_and_send(&self.context).await {
self.state.fail_count += 1;
self.state.last_retry = Some(Utc::now());
let retry_delay: Duration = federate_retry_sleep_duration(self.state.fail_count);
info!(
"{}: retrying {:?} attempt {} with delay {retry_delay:.2?}. ({e})",
self.instance.domain, activity.id, self.state.fail_count
);
self.save_and_send_state().await?;
tokio::select! {
() = sleep(retry_delay) => {},
() = self.stop.cancelled() => {
// save state to db and exit
return Ok(());
}
}
}
// Activity send successful, mark instance as alive if it hasn't been updated in a while.
let updated = self.instance.updated.unwrap_or(self.instance.published);
if updated.add(Days::new(1)) < Utc::now() {
self.instance.updated = Some(Utc::now());
let form = InstanceForm::builder()
.domain(self.instance.domain.clone())
.updated(Some(naive_now()))
.build();
Instance::update(&mut self.context.pool(), self.instance.id, form).await?;
}
}
Ok(())
}
/// get inbox urls of sending the given activity to the given instance
/// most often this will return 0 values (if instance doesn't care about the activity)
/// or 1 value (the shared inbox)
/// > 1 values only happens for non-lemmy software
async fn get_inbox_urls(&mut self, activity: &SentActivity) -> Result<HashSet<Url>> {
let mut inbox_urls: HashSet<Url> = HashSet::new();
if activity.send_all_instances {
if !self.site_loaded {
self.site = Site::read_from_instance_id(&mut self.context.pool(), self.instance.id).await?;
self.site_loaded = true;
}
if let Some(site) = &self.site {
// Nutomic: Most non-lemmy software wont have a site row. That means it cant handle these
// activities. So handling it like this is fine.
inbox_urls.insert(site.inbox_url.inner().clone());
}
}
if let Some(t) = &activity.send_community_followers_of {
if let Some(urls) = self.followed_communities.get(t) {
inbox_urls.extend(urls.iter().cloned());
}
}
inbox_urls.extend(
activity
.send_inboxes
.iter()
.filter_map(std::option::Option::as_ref)
.filter(|&u| (u.domain() == Some(&self.instance.domain)))
.map(|u| u.inner().clone()),
);
Ok(inbox_urls)
}
async fn update_communities(&mut self) -> Result<()> {
if (Utc::now() - self.last_full_communities_fetch) > *FOLLOW_REMOVALS_RECHECK_DELAY {
// process removals every hour
(self.followed_communities, self.last_full_communities_fetch) = self
.get_communities(self.instance.id, Utc.timestamp_nanos(0))
.await?;
self.last_incremental_communities_fetch = self.last_full_communities_fetch;
}
if (Utc::now() - self.last_incremental_communities_fetch) > *FOLLOW_ADDITIONS_RECHECK_DELAY {
// process additions every minute
let (news, time) = self
.get_communities(self.instance.id, self.last_incremental_communities_fetch)
.await?;
self.followed_communities.extend(news);
self.last_incremental_communities_fetch = time;
}
Ok(())
}
/// get a list of local communities with the remote inboxes on the given instance that cares about
/// them
async fn get_communities(
&mut self,
instance_id: InstanceId,
last_fetch: DateTime<Utc>,
) -> Result<(HashMap<CommunityId, HashSet<Url>>, DateTime<Utc>)> {
let new_last_fetch =
Utc::now() - chrono::TimeDelta::try_seconds(10).expect("TimeDelta out of bounds"); // update to time before fetch to ensure overlap. subtract 10s to ensure overlap even if
// published date is not exact
Ok((
CommunityFollowerView::get_instance_followed_community_inboxes(
&mut self.context.pool(),
instance_id,
last_fetch,
)
.await?
.into_iter()
.fold(HashMap::new(), |mut map, (c, u)| {
map.entry(c).or_default().insert(u.into());
map
}),
new_last_fetch,
))
}
async fn save_and_send_state(&mut self) -> Result<()> {
self.last_state_insert = Utc::now();
FederationQueueState::upsert(&mut self.context.pool(), &self.state).await?;
self.stats_sender.send(FederationQueueStateWithDomain {
state: self.state.clone(),
domain: self.instance.domain.clone(),
})?;
Ok(())
}
}