refactor (backend-rs): rework static cache

Co-authored-by: sup39 <dev@sup39.dev>

packages/backend-rs/src/cache/bare.rs

@@ -0,0 +1,53 @@
+//! In-memory cache handler
+
+use chrono::{DateTime, Duration, Utc};
+use std::sync::Mutex;
+
+pub struct Cache<T: Clone> {
+    cache: Mutex<TimedData<T>>,
+    ttl: Option<Duration>,
+}
+
+struct TimedData<T: Clone> {
+    value: Option<T>,
+    last_updated: DateTime<Utc>,
+}
+
+impl<T: Clone> Cache<T> {
+    pub const fn new(ttl: Option<Duration>) -> Self {
+        Self {
+            cache: Mutex::new(TimedData {
+                value: None,
+                last_updated: DateTime::UNIX_EPOCH,
+            }),
+            ttl,
+        }
+    }
+
+    pub fn set(&self, value: T) {
+        if self.ttl.is_none() {
+            let _ = self
+                .cache
+                .lock()
+                .map(|mut cache| (*cache).value = Some(value));
+        } else {
+            let _ = self.cache.lock().map(|mut cache| {
+                *cache = TimedData {
+                    value: Some(value),
+                    last_updated: Utc::now(),
+                }
+            });
+        }
+    }
+
+    pub fn get(&self) -> Option<T> {
+        let data = self.cache.lock().ok()?;
+
+        if let Some(ttl) = self.ttl {
+            if data.last_updated + ttl < Utc::now() {
+                return None;
+            }
+        }
+        data.value.to_owned()
+    }
+}

packages/backend-rs/src/cache/mod.rs

@@ -0,0 +1,3 @@
+pub mod bare;
+
+pub use bare::Cache;

packages/backend-rs/src/config/meta.rs

@@ -1,15 +1,11 @@
 //! Server information
 
-use crate::{database::db_conn, model::entity::meta};
+use crate::{cache::Cache, database::db_conn, model::entity::meta};
 use sea_orm::{prelude::*, ActiveValue};
-use std::sync::Mutex;
 
 type Meta = meta::Model;
 
-static CACHE: Mutex<Option<Meta>> = Mutex::new(None);
-fn set_cache(meta: &Meta) {
-    let _ = CACHE.lock().map(|mut cache| *cache = Some(meta.clone()));
-}
+static INSTANCE_META_CACHE: Cache<Meta> = Cache::new(None);
 
 #[macros::export(js_name = "fetchMeta")]
 pub async fn local_server_info() -> Result<Meta, DbErr> {
@@ -25,7 +21,7 @@ pub async fn update() -> Result<(), DbErr> {
 async fn local_server_info_impl(use_cache: bool) -> Result<Meta, DbErr> {
     // try using cache
     if use_cache {
-        if let Some(cache) = CACHE.lock().ok().and_then(|cache| cache.clone()) {
+        if let Some(cache) = INSTANCE_META_CACHE.get() {
             return Ok(cache);
         }
     }
@@ -34,7 +30,7 @@ async fn local_server_info_impl(use_cache: bool) -> Result<Meta, DbErr> {
     let db = db_conn().await?;
     let meta = meta::Entity::find().one(db).await?;
     if let Some(meta) = meta {
-        set_cache(&meta);
+        INSTANCE_META_CACHE.set(meta.clone());
         return Ok(meta);
     }
 
@@ -45,7 +41,7 @@ async fn local_server_info_impl(use_cache: bool) -> Result<Meta, DbErr> {
     })
     .exec_with_returning(db)
     .await?;
-    set_cache(&meta);
+    INSTANCE_META_CACHE.set(meta.clone());
     Ok(meta)
 }
 

packages/backend-rs/src/federation/nodeinfo/generate.rs

@@ -1,6 +1,7 @@
 //! NodeInfo generator
 
 use crate::{
+    cache::Cache,
     config::{local_server_info, CONFIG},
     database::db_conn,
     federation::nodeinfo::schema::*,
@@ -9,15 +10,9 @@ use crate::{
 };
 use sea_orm::prelude::*;
 use serde_json::json;
-use std::{collections::HashMap, sync::Mutex};
+use std::collections::HashMap;
 
-static CACHE: Mutex<Option<Nodeinfo21>> = Mutex::new(None);
-
-fn set_cache(nodeinfo: &Nodeinfo21) {
-    let _ = CACHE
-        .lock()
-        .map(|mut cache| *cache = Some(nodeinfo.to_owned()));
-}
+static NODEINFO_CACHE: Cache<Nodeinfo21> = Cache::new(None);
 
 /// Fetches the number of total/active local users and local posts.
 ///
@@ -129,7 +124,7 @@ async fn generate_nodeinfo_2_1() -> Result<Nodeinfo21, DbErr> {
 
 async fn nodeinfo_2_1_impl(use_cache: bool) -> Result<Nodeinfo21, DbErr> {
     if use_cache {
-        if let Some(nodeinfo) = CACHE.lock().ok().and_then(|cache| cache.to_owned()) {
+        if let Some(nodeinfo) = NODEINFO_CACHE.get() {
             return Ok(nodeinfo);
         }
     }
@@ -137,7 +132,7 @@ async fn nodeinfo_2_1_impl(use_cache: bool) -> Result<Nodeinfo21, DbErr> {
     let nodeinfo = generate_nodeinfo_2_1().await?;
 
     tracing::info!("updating cache");
-    set_cache(&nodeinfo);
+    NODEINFO_CACHE.set(nodeinfo.clone());
 
     Ok(nodeinfo)
 }

packages/backend-rs/src/lib.rs

@@ -1,5 +1,6 @@
 #![doc = include_str!(concat!(env!("CARGO_MANIFEST_DIR"), "/README.md"))]
 
+pub mod cache;
 pub mod config;
 pub mod database;
 pub mod federation;

packages/backend-rs/src/service/antenna/cache.rs

@@ -1,26 +0,0 @@
-//! In-memory antennas cache handler
-
-use crate::{database::db_conn, model::entity::antenna};
-use sea_orm::prelude::*;
-use std::sync::{Arc, Mutex};
-
-static CACHE: Mutex<Option<Arc<[antenna::Model]>>> = Mutex::new(None);
-
-fn set(antennas: Arc<[antenna::Model]>) {
-    let _ = CACHE.lock().map(|mut cache| *cache = Some(antennas));
-}
-
-pub(super) async fn update() -> Result<Arc<[antenna::Model]>, DbErr> {
-    tracing::debug!("updating cache");
-    let antennas: Arc<[antenna::Model]> =
-        antenna::Entity::find().all(db_conn().await?).await?.into();
-    set(antennas.clone());
-    Ok(antennas)
-}
-
-pub(super) async fn get() -> Result<Arc<[antenna::Model]>, DbErr> {
-    if let Some(cache) = CACHE.lock().ok().and_then(|cache| cache.clone()) {
-        return Ok(cache);
-    }
-    update().await
-}

packages/backend-rs/src/service/antenna/mod.rs

@@ -1,4 +1,24 @@
-mod cache;
 mod check_hit;
 pub mod process_new_note;
 pub mod update;
+
+use crate::{cache::Cache, database::db_conn, model::entity::antenna};
+use sea_orm::prelude::*;
+use std::sync::Arc;
+
+static ANTENNAS_CACHE: Cache<Arc<[antenna::Model]>> = Cache::new(None);
+
+async fn update() -> Result<Arc<[antenna::Model]>, DbErr> {
+    tracing::debug!("updating cache");
+    let antennas: Arc<[antenna::Model]> =
+        antenna::Entity::find().all(db_conn().await?).await?.into();
+    ANTENNAS_CACHE.set(antennas.clone());
+    Ok(antennas)
+}
+
+async fn get_antennas() -> Result<Arc<[antenna::Model]>, DbErr> {
+    if let Some(cache) = ANTENNAS_CACHE.get() {
+        return Ok(cache);
+    }
+    update().await
+}

packages/backend-rs/src/service/antenna/process_new_note.rs

@@ -46,7 +46,7 @@ pub async fn update_antennas_on_new_note(
     let note_all_texts = elaborate!(note, false).await?;
 
     // TODO: do this in parallel
-    for antenna in antenna::cache::get().await?.iter() {
+    for antenna in antenna::get_antennas().await?.iter() {
         if note_muted_users.contains(&antenna.user_id) {
             continue;
         }

packages/backend-rs/src/service/antenna/update.rs

@@ -2,6 +2,6 @@
 
 #[macros::ts_export]
 pub async fn update_antenna_cache() -> Result<(), sea_orm::DbErr> {
-    super::cache::update().await?;
+    super::update().await?;
     Ok(())
 }