Move task to separate function

src/cache/low_mem.rs

@@ -10,8 +10,8 @@ use futures::StreamExt;
 use log::{warn, LevelFilter};
 use sqlx::sqlite::SqliteConnectOptions;
 use sqlx::{ConnectOptions, SqlitePool};
-use tokio::fs::remove_file;
 use tokio::sync::mpsc::{channel, Sender};
+use tokio::{fs::remove_file, sync::mpsc::Receiver};
 use tokio_stream::wrappers::ReceiverStream;
 
 use super::{BoxedImageStream, Cache, CacheError, CacheKey, CacheStream, ImageMetadata};
@@ -57,76 +57,77 @@ impl LowMemCache {
             db_update_channel_sender: db_tx,
         }));
 
-        // Spawns a new task that continuously listens for events received by
-        // the channel, which informs the low memory cache the total size of the
-        // item that was put into the cache.
-        let new_self_0 = Arc::clone(&new_self);
+        tokio::spawn(db_listener(
+            Arc::clone(&new_self),
+            db_rx,
+            db_pool,
+            disk_max_size / 20 * 19,
+        ));
 
-        // Spawn a new task that will listen for updates to the db, pruning if
-        // the size becomes too large
-        tokio::spawn(async move {
-            let db_pool = db_pool;
-            let max_on_disk_size = disk_max_size / 20 * 19;
-            let mut recv_stream = ReceiverStream::new(db_rx).ready_chunks(128);
-            while let Some(messages) = recv_stream.next().await {
-                let now = chrono::Utc::now();
-                let mut transaction = db_pool.begin().await.unwrap();
-                for message in messages {
-                    match message {
-                        DbMessage::Get(entry) => {
-                            let key = entry.as_os_str().to_str();
-                            let query = sqlx::query!(
-                                "update Images set accessed = ? where id = ?",
-                                now,
-                                key
-                            )
+        new_self
+    }
+}
+
+/// Spawn a new task that will listen for updates to the db, pruning if the size
+/// becomes too large.
+async fn db_listener(
+    cache: Arc<Box<dyn Cache>>,
+    db_rx: Receiver<DbMessage>,
+    db_pool: SqlitePool,
+    max_on_disk_size: u64,
+) {
+    let mut recv_stream = ReceiverStream::new(db_rx).ready_chunks(128);
+    while let Some(messages) = recv_stream.next().await {
+        let now = chrono::Utc::now();
+        let mut transaction = db_pool.begin().await.unwrap();
+        for message in messages {
+            match message {
+                DbMessage::Get(entry) => {
+                    let key = entry.as_os_str().to_str();
+                    let query =
+                        sqlx::query!("update Images set accessed = ? where id = ?", now, key)
                             .execute(&mut transaction)
                             .await;
-                            if let Err(e) = query {
-                                warn!("Failed to update timestamp in db for {:?}: {}", key, e);
-                            }
-                        }
-                        DbMessage::Put(entry, size) => {
-                            let key = entry.as_os_str().to_str();
-                            let query = sqlx::query!(
-                                "insert into Images (id, size, accessed) values (?, ?, ?)",
-                                key,
-                                size,
-                                now,
-                            )
-                            .execute(&mut transaction)
-                            .await;
-                            if let Err(e) = query {
-                                warn!("Failed to add {:?} to db: {}", key, e);
-                            }
-
-                            new_self_0.increase_usage(size);
-                        }
+                    if let Err(e) = query {
+                        warn!("Failed to update timestamp in db for {:?}: {}", key, e);
                     }
                 }
-                transaction.commit().await.unwrap();
-
-                if new_self_0.on_disk_size() >= max_on_disk_size {
-                    let mut conn = db_pool.acquire().await.unwrap();
-                    let items = sqlx::query!(
-                        "select id, size from Images order by accessed asc limit 1000"
+                DbMessage::Put(entry, size) => {
+                    let key = entry.as_os_str().to_str();
+                    let query = sqlx::query!(
+                        "insert into Images (id, size, accessed) values (?, ?, ?)",
+                        key,
+                        size,
+                        now,
                     )
+                    .execute(&mut transaction)
+                    .await;
+                    if let Err(e) = query {
+                        warn!("Failed to add {:?} to db: {}", key, e);
+                    }
+
+                    cache.increase_usage(size);
+                }
+            }
+        }
+        transaction.commit().await.unwrap();
+
+        if cache.on_disk_size() >= max_on_disk_size {
+            let mut conn = db_pool.acquire().await.unwrap();
+            let items =
+                sqlx::query!("select id, size from Images order by accessed asc limit 1000")
                     .fetch_all(&mut conn)
                     .await
                     .unwrap();
 
-                    let mut size_freed = 0;
-                    for item in items {
-                        size_freed += item.size as u64;
-                        tokio::spawn(remove_file(item.id));
-                    }
-
-                    new_self_0.decrease_usage(size_freed);
-                }
+            let mut size_freed = 0;
+            for item in items {
+                size_freed += item.size as u64;
+                tokio::spawn(remove_file(item.id));
             }
-        });
 
-        new_self
+            cache.decrease_usage(size_freed);
+        }
     }
 }
 
@@ -150,7 +151,7 @@ impl Cache for LowMemCache {
 
     async fn put(
         &self,
-        key: &CacheKey,
+        key: CacheKey,
         image: BoxedImageStream,
         metadata: ImageMetadata,
     ) -> Result<CacheStream, CacheError> {
@@ -162,6 +163,7 @@ impl Cache for LowMemCache {
         let db_callback = |size: u32| async move {
             let _ = channel.send(DbMessage::Put(path_0, size)).await;
         };
+
         super::fs::write_file(&path, image, metadata, db_callback)
             .await
             .map_err(Into::into)

src/cache/mod.rs

@@ -157,7 +157,7 @@ pub trait Cache: Send + Sync {
 
     async fn put(
         &self,
-        key: &CacheKey,
+        key: CacheKey,
         image: BoxedImageStream,
         metadata: ImageMetadata,
     ) -> Result<CacheStream, CacheError>;

src/routes.rs

@@ -263,7 +263,7 @@ async fn fetch_image(
 
             let metadata = ImageMetadata::new(content_type, length, last_mod).unwrap();
             let stream = {
-                match cache.put(&key, Box::new(body), metadata).await {
+                match cache.put(key, Box::new(body), metadata).await {
                     Ok(stream) => stream,
                     Err(e) => {
                         warn!("Failed to insert into cache: {}", e);