Add queue for incoming activities, to sort them by published

Cargo.lock

@@ -17,8 +17,7 @@ checksum = "8f27d075294830fcab6f66e320dab524bc6d048f4a151698e153205559113772"
 [[package]]
 name = "activitypub_federation"
 version = "0.5.2"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "a028034c642d3ed16b535f98f48b3df30397833c183d68852d79de16650d5ed5"
+source = "git+https://github.com/LemmyNet/activitypub-federation-rust.git?branch=actix-inbox-parts#b393221b10ed6fdd879e78e6c842b9714baa0f95"
 dependencies = [
  "activitystreams-kinds",
  "actix-web",

Cargo.toml

@@ -96,7 +96,7 @@ lemmy_routes = { version = "=0.19.3", path = "./crates/routes" }
 lemmy_db_views = { version = "=0.19.3", path = "./crates/db_views" }
 lemmy_db_views_actor = { version = "=0.19.3", path = "./crates/db_views_actor" }
 lemmy_db_views_moderator = { version = "=0.19.3", path = "./crates/db_views_moderator" }
-activitypub_federation = { version = "0.5.2", default-features = false, features = [
+activitypub_federation = { git = "https://github.com/LemmyNet/activitypub-federation-rust.git", branch = "actix-inbox-parts", default-features = false, features = [
   "actix-web",
 ] }
 diesel = "2.1.4"

crates/apub/src/activities/mod.rs

@@ -45,6 +45,7 @@ use lemmy_db_schema::{
 use lemmy_db_views_actor::structs::{CommunityPersonBanView, CommunityView};
 use lemmy_utils::error::{LemmyError, LemmyErrorExt, LemmyErrorType, LemmyResult};
 use serde::Serialize;
+use serde_with::serde_derive::Deserialize;
 use tracing::info;
 use url::{ParseError, Url};
 use uuid::Uuid;
@@ -227,9 +228,9 @@ where
 
 /// Wrapper struct that adds `published` field with timestamp to outgoing activities. Important that
 /// the timestamp includes milliseconds and timezone.
-#[derive(Serialize)]
-struct WithPublished<T> {
-  published: DateTime<Utc>,
+#[derive(Serialize, Deserialize)]
+pub(crate) struct WithPublished<T> {
+  pub(crate) published: Option<DateTime<Utc>>,
   #[serde(flatten)]
   inner: T,
 }
@@ -237,7 +238,7 @@ struct WithPublished<T> {
 impl<T> WithPublished<T> {
   pub fn new(inner: T) -> WithPublished<T> {
     Self {
-      published: Local::now().into(),
+      published: Some(Local::now().into()),
       inner,
     }
   }

crates/apub/src/http/inbox.rs

@@ -0,0 +1,171 @@
+use crate::{
+  activities::WithPublished,
+  activity_lists::SharedInboxActivities,
+  fetcher::user_or_community::UserOrCommunity,
+};
+use activitypub_federation::{
+  actix_web::inbox::{receive_activity, receive_activity_parts},
+  config::Data,
+};
+use actix_web::{http::header::HeaderMap, web::Bytes, HttpRequest, HttpResponse};
+use chrono::{DateTime, Local, TimeDelta, Utc};
+use http::{Method, Uri};
+use lemmy_api_common::context::LemmyContext;
+use lemmy_utils::error::LemmyResult;
+use once_cell::sync::Lazy;
+use std::{
+  cmp::Ordering,
+  collections::BinaryHeap,
+  sync::{Arc, Mutex},
+  thread::available_parallelism,
+  time::Duration,
+};
+use tokio::{spawn, task::JoinHandle, time::sleep};
+use tracing::info;
+
+/// Handle incoming activities.
+pub async fn shared_inbox(
+  request: HttpRequest,
+  bytes: Bytes,
+  data: Data<LemmyContext>,
+) -> LemmyResult<HttpResponse> {
+  match serde_json::from_slice::<WithPublished<()>>(&bytes)?.published {
+    Some(published) => {
+      // includes published timestamp, insert to queue to ensure that activities are processed
+      // in correct order even when delivered out of order.
+      let request_parts = (
+        request.headers().clone(),
+        request.method().clone(),
+        request.uri().clone(),
+      );
+      ACTIVITY_QUEUE.lock().unwrap().push(InboxActivity {
+        request_parts,
+        bytes,
+        published,
+      });
+    }
+    None => {
+      // no timestamp included, process immediately
+      receive_activity::<SharedInboxActivities, UserOrCommunity, LemmyContext>(
+        request, bytes, &data,
+      )
+      .await?;
+    }
+  };
+  Ok(HttpResponse::Ok().finish())
+}
+
+/// Queue of incoming activities, ordered by oldest published first
+static ACTIVITY_QUEUE: Lazy<Arc<Mutex<BinaryHeap<InboxActivity>>>> =
+  Lazy::new(|| Arc::new(Mutex::new(BinaryHeap::new())));
+
+/// Minimum age of an activity before it gets processed. This ensures that an activity which was
+/// delayed still gets processed in correct order.
+const RECEIVE_DELAY: Option<TimeDelta> = TimeDelta::try_seconds(1);
+
+pub fn handle_received_activities(
+  context: &Data<LemmyContext>,
+) -> LemmyResult<Vec<JoinHandle<()>>> {
+  // launch one task per cpu core
+  let parallelism = available_parallelism()?.into();
+  let workers = (0..parallelism)
+    .map(|_| {
+      let context = context.reset_request_count();
+      spawn(async move {
+        loop {
+          let now = Local::now();
+          if let Some(latest_timestamp) = peek_queue_timestamp() {
+            if latest_timestamp < now - RECEIVE_DELAY.unwrap() {
+              if let Some(a) = pop_queue() {
+                let parts = (&a.request_parts.0, &a.request_parts.1, &a.request_parts.2);
+                receive_activity_parts::<SharedInboxActivities, UserOrCommunity, LemmyContext>(
+                  parts, a.bytes, &context,
+                )
+                .await
+                .inspect_err(|e| info!("Error receiving activity: {e}"))
+                .ok();
+              }
+            }
+          }
+          // TODO: could sleep based on remaining time until head activity reaches 1s
+          //       or simply use `WORK_FINISHED_RECHECK_DELAY` from lemmy_federate
+          sleep(Duration::from_millis(100)).await;
+          // TODO: need cancel? lemmy seems to shutdown just fine
+        }
+      })
+    })
+    .collect();
+
+  Ok(workers)
+}
+
+fn peek_queue_timestamp() -> Option<DateTime<Utc>> {
+  ACTIVITY_QUEUE.lock().unwrap().peek().map(|i| i.published)
+}
+
+fn pop_queue<'a>() -> Option<InboxActivity> {
+  ACTIVITY_QUEUE.lock().unwrap().pop()
+}
+
+#[derive(Clone, Debug)]
+struct InboxActivity {
+  // Need to store like this because HttpRequest is not Sync
+  request_parts: (HeaderMap, Method, Uri),
+  bytes: Bytes,
+  published: DateTime<Utc>,
+}
+
+impl PartialOrd for InboxActivity {
+  fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
+    other.published.partial_cmp(&self.published)
+  }
+}
+
+impl Ord for InboxActivity {
+  fn cmp(&self, other: &Self) -> Ordering {
+    other.published.cmp(&self.published)
+  }
+}
+
+impl PartialEq for InboxActivity {
+  fn eq(&self, other: &Self) -> bool {
+    self.bytes.eq(&other.bytes)
+  }
+}
+
+impl Eq for InboxActivity {}
+
+#[cfg(test)]
+mod tests {
+  use super::*;
+
+  #[test]
+  fn activity_queue_order() {
+    let activity1 = InboxActivity {
+      request_parts: Default::default(),
+      bytes: Default::default(),
+      published: Local::now().into(),
+    };
+    let activity2 = InboxActivity {
+      request_parts: Default::default(),
+      bytes: Default::default(),
+      published: Local::now().into(),
+    };
+    let activity3 = InboxActivity {
+      request_parts: Default::default(),
+      bytes: Default::default(),
+      published: Local::now().into(),
+    };
+    let mut lock = ACTIVITY_QUEUE.lock().unwrap();
+
+    // insert in wrong order
+    lock.push(activity3.clone());
+    lock.push(activity1.clone());
+    lock.push(activity2.clone());
+
+    // should be popped in correct order
+    assert_eq!(activity1.published, lock.pop().unwrap().published);
+    assert_eq!(activity2.published, lock.pop().unwrap().published);
+    assert_eq!(activity3.published, lock.pop().unwrap().published);
+  }
+}

crates/apub/src/http/mod.rs

@@ -1,16 +1,6 @@
-use crate::{
-  activity_lists::SharedInboxActivities,
-  fetcher::user_or_community::UserOrCommunity,
-  protocol::objects::tombstone::Tombstone,
-  FEDERATION_CONTEXT,
-};
-use activitypub_federation::{
-  actix_web::inbox::receive_activity,
-  config::Data,
-  protocol::context::WithContext,
-  FEDERATION_CONTENT_TYPE,
-};
-use actix_web::{web, web::Bytes, HttpRequest, HttpResponse};
+use crate::{protocol::objects::tombstone::Tombstone, FEDERATION_CONTEXT};
+use activitypub_federation::{protocol::context::WithContext, FEDERATION_CONTENT_TYPE};
+use actix_web::{web, HttpResponse};
 use http::{header::LOCATION, StatusCode};
 use lemmy_api_common::context::LemmyContext;
 use lemmy_db_schema::{
@@ -25,20 +15,12 @@ use url::Url;
 
 mod comment;
 mod community;
+pub mod inbox;
 mod person;
 mod post;
 pub mod routes;
 pub mod site;
 
-pub async fn shared_inbox(
-  request: HttpRequest,
-  body: Bytes,
-  data: Data<LemmyContext>,
-) -> LemmyResult<HttpResponse> {
-  receive_activity::<SharedInboxActivities, UserOrCommunity, LemmyContext>(request, body, &data)
-    .await
-}
-
 /// Convert the data to json and turn it into an HTTP Response with the correct ActivityPub
 /// headers.
 ///

crates/apub/src/http/routes.rs

@@ -9,9 +9,9 @@ use crate::http::{
     get_apub_community_outbox,
   },
   get_activity,
+  inbox::shared_inbox,
   person::{get_apub_person_http, get_apub_person_outbox, person_inbox},
   post::get_apub_post,
-  shared_inbox,
   site::{get_apub_site_http, get_apub_site_outbox},
 };
 use actix_web::{

crates/db_views/src/custom_emoji_view.rs

@@ -77,7 +77,7 @@ impl CustomEmojiView {
     }
     for emoji in &mut result {
       if let Some(keywords) = hash.get_mut(&emoji.custom_emoji.id) {
-        emoji.keywords = keywords.clone();
+        emoji.keywords.clone_from(keywords);
       }
     }
     result

src/lib.rs

@@ -25,6 +25,7 @@ use actix_web::{
 };
 use actix_web_prom::PrometheusMetricsBuilder;
 use clap::Parser;
+use futures_util::future::join_all;
 use lemmy_api_common::{
   context::LemmyContext,
   lemmy_db_views::structs::SiteView,
@@ -37,6 +38,7 @@ use lemmy_api_common::{
 };
 use lemmy_apub::{
   activities::{handle_outgoing_activities, match_outgoing_activities},
+  http::inbox::handle_received_activities,
   objects::instance::ApubSite,
   VerifyUrlData,
   FEDERATION_HTTP_FETCH_LIMIT,
@@ -192,6 +194,8 @@ pub async fn start_lemmy_server(args: CmdArgs) -> Result<(), LemmyError> {
     .expect("set function pointer");
   let request_data = federation_config.to_request_data();
   let outgoing_activities_task = tokio::task::spawn(handle_outgoing_activities(request_data));
+  let request_data = federation_config.to_request_data();
+  let handle_received_activities_task = handle_received_activities(&request_data);
 
   let server = if !args.disable_http_server {
     if let Some(startup_server_handle) = startup_server_handle {
@@ -239,6 +243,7 @@ pub async fn start_lemmy_server(args: CmdArgs) -> Result<(), LemmyError> {
 
   // Wait for outgoing apub sends to complete
   ActivityChannel::close(outgoing_activities_task).await?;
+  join_all(handle_received_activities_task?).await;
 
   Ok(())
 }