http: reload tls config on SIGUSR1

crates/http/src/config.rs

@@ -77,6 +77,12 @@ pub struct NetworkConfig {
     /// Maximum number of pending TCP connections
     pub tcp_backlog: i32,
     /// Path to TLS certificate (DER-encoded X.509)
+    ///
+    /// The TLS files are read on start and when the program receives `SIGUSR1`.
+    /// If initial parsing fails, the program exits. Later failures result in
+    /// in emitting of an error-level log message, while successful updates
+    /// result in emitting of an info-level log message. Updates only affect
+    /// new connections.
     pub tls_certificate_path: PathBuf,
     /// Path to TLS private key (DER-encoded ASN.1 in PKCS#8 or PKCS#1 format)
     pub tls_private_key_path: PathBuf,

crates/http/src/lib.rs

@@ -9,6 +9,7 @@ use aquatic_common::{
     rustls_config::create_rustls_config,
     PanicSentinelWatcher, ServerStartInstant,
 };
+use arc_swap::ArcSwap;
 use common::State;
 use glommio::{channels::channel_mesh::MeshBuilder, prelude::*};
 use signal_hook::{
@@ -57,10 +58,10 @@ pub fn run(config: Config) -> ::anyhow::Result<()> {
     let (sentinel_watcher, sentinel) = PanicSentinelWatcher::create_with_sentinel();
     let priv_dropper = PrivilegeDropper::new(config.privileges.clone(), config.socket_workers);
 
-    let tls_config = Arc::new(create_rustls_config(
+    let tls_config = Arc::new(ArcSwap::from_pointee(create_rustls_config(
         &config.network.tls_certificate_path,
         &config.network.tls_private_key_path,
-    )?);
+    )?));
 
     let server_start_instant = ServerStartInstant::new();
 
@@ -144,6 +145,18 @@ pub fn run(config: Config) -> ::anyhow::Result<()> {
         match signal {
             SIGUSR1 => {
                 let _ = update_access_list(&config.access_list, &state.access_list);
+
+                match create_rustls_config(
+                    &config.network.tls_certificate_path,
+                    &config.network.tls_private_key_path,
+                ) {
+                    Ok(config) => {
+                        tls_config.store(Arc::new(config));
+
+                        ::log::info!("successfully updated tls config");
+                    }
+                    Err(err) => ::log::error!("could not update tls config: {:#}", err),
+                }
             }
             SIGTERM => {
                 if sentinel_watcher.panic_was_triggered() {

crates/http/src/workers/socket.rs

@@ -15,6 +15,7 @@ use aquatic_http_protocol::request::{Request, RequestParseError, ScrapeRequest};
 use aquatic_http_protocol::response::{
     FailureResponse, Response, ScrapeResponse, ScrapeStatistics,
 };
+use arc_swap::ArcSwap;
 use either::Either;
 use futures::stream::FuturesUnordered;
 use futures_lite::{AsyncReadExt, AsyncWriteExt, StreamExt};
@@ -59,7 +60,7 @@ pub async fn run_socket_worker(
     _sentinel: PanicSentinel,
     config: Config,
     state: State,
-    tls_config: Arc<RustlsConfig>,
+    tls_config: Arc<ArcSwap<RustlsConfig>>,
     request_mesh_builder: MeshBuilder<ChannelRequest, Partial>,
     priv_dropper: PrivilegeDropper,
     server_start_instant: ServerStartInstant,
@@ -208,12 +209,12 @@ impl Connection {
         request_senders: Rc<Senders<ChannelRequest>>,
         server_start_instant: ServerStartInstant,
         connection_id: ConnectionId,
-        tls_config: Arc<RustlsConfig>,
+        tls_config: Arc<ArcSwap<RustlsConfig>>,
         connection_slab: Rc<RefCell<Slab<ConnectionReference>>>,
         stream: TcpStream,
         peer_addr: CanonicalSocketAddr,
     ) -> anyhow::Result<()> {
-        let tls_acceptor: TlsAcceptor = tls_config.into();
+        let tls_acceptor: TlsAcceptor = tls_config.load_full().into();
         let stream = tls_acceptor.accept(stream).await?;
 
         let mut response_buffer = [0; RESPONSE_BUFFER_SIZE];