feat: open file semaphore

torrential/Cargo.lock

@@ -547,6 +547,15 @@ version = "2.3.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "37909eebbb50d72f9059c3b6d82c0463f2ff062c9e95845c43a6c9c0355411be"
 
+[[package]]
+name = "file_open_limit"
+version = "0.0.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a2a1c2ca7813e68cf8e8aa5fbfe64016332355b70495d57e69df4058fd08cdbb"
+dependencies = [
+ "rlimit",
+]
+
 [[package]]
 name = "find-msvc-tools"
 version = "0.1.5"
@@ -1475,6 +1484,15 @@ dependencies = [
  "windows-sys 0.52.0",
 ]
 
+[[package]]
+name = "rlimit"
+version = "0.8.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f7278a1ec8bfd4a4e07515c589f5ff7b309a373f987393aef44813d9dcf87aa3"
+dependencies = [
+ "libc",
+]
+
 [[package]]
 name = "rustc-hash"
 version = "2.1.1"
@@ -1915,8 +1933,10 @@ dependencies = [
  "ctr",
  "dashmap",
  "droplet-rs",
+ "file_open_limit",
  "futures-util",
  "log",
+ "pin-project-lite",
  "rand",
  "reqwest",
  "serde",

torrential/Cargo.toml

@@ -34,6 +34,8 @@ futures-util = "0.3.31"
 ctr = "0.9.2"
 aes = "0.8.4"
 bytes = "*"
+file_open_limit = "0.0.5"
+pin-project-lite = "0.2.16"
 
 [lints.clippy]
 pedantic = { level = "warn", priority = -1 }

torrential/src/main.rs

@@ -1,6 +1,7 @@
 use std::{
     env::{self, set_current_dir},
     sync::Arc,
+    time::{Duration, Instant},
 };
 
 use axum::{
@@ -10,10 +11,12 @@ use axum::{
 use dashmap::DashMap;
 use log::info;
 use simple_logger::SimpleLogger;
-use tokio::{runtime::Handle, sync::OnceCell};
+use tokio::{runtime::Handle, spawn, sync::OnceCell, time};
 use torrential::{handlers, serve, set_token, state::AppState};
 use url::Url;
 
+const CONTEXT_TTL: u64 = 10 * 60;
+
 #[tokio::main]
 async fn main() {
     initialise_logger();
@@ -31,6 +34,33 @@ async fn main() {
         context_cache: DashMap::new(),
     });
 
+    let interval_shared_state = shared_state.clone();
+
+    spawn(async move {
+        let shared_state = interval_shared_state;
+        let mut interval = time::interval(Duration::from_mins(1));
+
+        loop {
+            interval.tick().await;
+            let keys = shared_state
+                .context_cache
+                .iter()
+                .map(|v| v.key().clone())
+                .collect::<Vec<(String, String)>>();
+            for key in keys {
+                let last_access = if let Some(context) = shared_state.context_cache.get(&key) {
+                    context.last_access()
+                } else {
+                    Instant::now()
+                };
+                if last_access.elapsed().as_secs() >= CONTEXT_TTL {
+                    shared_state.context_cache.remove(&key);
+                    info!("cleaned context: {:?}", key);
+                }
+            }
+        }
+    });
+
     let app = setup_app(shared_state);
 
     serve(app).await.unwrap();

torrential/src/serve.rs

@@ -1,4 +1,9 @@
-use std::{io::Error, rc::Rc, sync::Arc};
+use std::{
+    cell::{LazyCell, OnceCell},
+    io::Error,
+    rc::Rc,
+    sync::{Arc, LazyLock},
+};
 
 use aes::cipher::{KeyIvInit, StreamCipher};
 use axum::{
@@ -13,10 +18,11 @@ use droplet_rs::{
     manifest::ChunkData,
     versions::types::{MinimumFileObject, VersionFile},
 };
-use futures_util::{StreamExt, stream};
+use futures_util::{Stream, StreamExt, stream};
 use log::{error, info};
-use reqwest::{StatusCode, header};
-use tokio::sync::SemaphorePermit;
+use pin_project_lite::pin_project;
+use reqwest::StatusCode;
+use tokio::sync::{Semaphore, SemaphorePermit};
 use tokio_util::io::ReaderStream;
 
 use crate::{
@@ -25,6 +31,44 @@ use crate::{
 
 type Aes128Ctr64LE = ctr::Ctr64LE<aes::Aes128>;
 
+pin_project! {
+    struct SemaphoreStream<'a, T>
+        where T: Stream
+    {
+        #[pin]
+        stream: T,
+        semaphore: SemaphorePermit<'a>,
+    }
+}
+
+impl<'a, T: Stream> SemaphoreStream<'a, T> {
+    fn new(stream: T, permit: SemaphorePermit<'a>) -> Self {
+        Self {
+            stream,
+            semaphore: permit,
+        }
+    }
+}
+
+impl<'a, T: Stream> Stream for SemaphoreStream<'a, T>
+where
+    T: Stream,
+{
+    type Item = T::Item;
+
+    fn poll_next(
+        self: std::pin::Pin<&mut Self>,
+        cx: &mut std::task::Context<'_>,
+    ) -> std::task::Poll<Option<Self::Item>> {
+        let this = self.project();
+        this.stream.poll_next(cx)
+    }
+}
+
+static SEMPAHORE_COUNT: LazyLock<usize> =
+    LazyLock::new(|| file_open_limit::get().expect("failed to count max open files"));
+static FILE_SEMAPHORE: LazyLock<Semaphore> = LazyLock::new(|| Semaphore::new(*SEMPAHORE_COUNT));
+
 pub async fn serve_file(
     State(state): State<Arc<AppState>>,
     Path((game_id, version_name, chunk_id)): Path<(String, String, String)>,
@@ -35,6 +79,13 @@ pub async fn serve_file(
     context.reset_last_access();
 
     let chunk_data = lookup_chunk(&chunk_id, &context)?;
+    if chunk_data.files.len() >= *SEMPAHORE_COUNT {
+        return Err(StatusCode::INSUFFICIENT_STORAGE);
+    }
+    let permit = FILE_SEMAPHORE
+        .acquire_many(chunk_data.files.len().try_into().unwrap())
+        .await
+        .map_err(|_| StatusCode::INSUFFICIENT_STORAGE)?;
     let mut streams = Vec::with_capacity(chunk_data.files.len());
     let mut content_length = 0;
 
@@ -54,7 +105,7 @@ pub async fn serve_file(
 
     let stream = stream::iter(streams).flatten();
     let mut cipher = Aes128Ctr64LE::new(&context.manifest.key.into(), &chunk_data.iv.into());
-    let encrypted_stream = stream.chunks(3).map(move |raw| -> Result<Bytes, Error> {
+    let encrypted_stream = stream.chunks(16).map(move |raw| -> Result<Bytes, Error> {
         let data: Result<Vec<Bytes>, Error> = raw.into_iter().collect();
         let mut data = data?.concat();
 
@@ -62,7 +113,8 @@ pub async fn serve_file(
 
         Ok(data.into())
     });
-    let body: Body = Body::from_stream(encrypted_stream);
+    let permit_stream = SemaphoreStream::new(encrypted_stream, permit);
+    let body: Body = Body::from_stream(permit_stream);
 
     let mut headers = HeaderMap::new();
     headers.insert("Content-Type", "application/octet-stream".parse().unwrap());

torrential/src/state.rs

@@ -1,7 +1,7 @@
-use std::{collections::HashMap, path::PathBuf};
+use std::{collections::HashMap, path::PathBuf, sync::Arc};
 
 use dashmap::DashMap;
-use tokio::sync::OnceCell;
+use tokio::sync::{OnceCell, Semaphore};
 
 use crate::
  DownloadContext