add file watcher for dev

kitsune/Cargo.toml

@@ -16,6 +16,7 @@ eula = false
 
 [dependencies]
 athena.workspace = true
+arc-swap = "1.7.1"
 argon2 = { version = "0.5.3", features = ["std"] }
 async-trait = "0.1.83"
 axum = { version = "0.7.9", features = ["macros", "multipart"] }
@@ -70,6 +71,7 @@ mimalloc = "0.1.43"
 mime = "0.3.17"
 mime_guess = { version = "2.0.5", default-features = false }
 minijinja.workspace = true
+notify = "7.0.0"
 oxide-auth = "0.6.1"
 oxide-auth-async = "0.2.1"
 oxide-auth-axum = "0.5.0"
@@ -120,7 +122,6 @@ kitsune-mastodon = { workspace = true, optional = true }
 
 # "oidc" feature
 kitsune-oidc = { workspace = true, optional = true }
-arc-swap = "1.7.1"
 
 [dev-dependencies]
 kitsune-http-client.workspace = true

kitsune/src/template.rs

@@ -1,7 +1,8 @@
 use arc_swap::ArcSwapAny;
 use core::str;
+use notify::Watcher;
 use rust_embed::RustEmbed;
-use std::sync::OnceLock;
+use std::{mem::ManuallyDrop, path::Path, sync::OnceLock};
 use triomphe::Arc;
 
 static ENVIRONMENT: OnceLock<ArcSwapAny<Arc<minijinja::Environment<'static>>>> = OnceLock::new();
@@ -28,14 +29,36 @@ fn init_environment() -> minijinja::Environment<'static> {
     environment
 }
 
+fn spawn_watcher() {
+    let watcher = notify::recommended_watcher(|event: notify::Result<notify::Event>| {
+        if event.is_err() {
+            return;
+        }
+
+        ENVIRONMENT
+            .get()
+            .unwrap()
+            .store(Arc::new(init_environment()));
+    })
+    .unwrap();
+
+    let mut watcher = ManuallyDrop::new(watcher);
+    let template_dir = Path::new(concat!(env!("CARGO_MANIFEST_DIR"), "/templates"));
+
+    watcher
+        .watch(template_dir, notify::RecursiveMode::Recursive)
+        .unwrap();
+}
+
 #[track_caller]
 pub fn render<S>(name: &str, ctx: S) -> Option<String>
 where
     S: serde::Serialize,
 {
     let handle = ENVIRONMENT
         .get_or_init(|| {
-            // ToDo: Spawn watcher on the path which replaces the environment through the arc-swap
+            #[cfg(debug_assertions)]
+            spawn_watcher();
             ArcSwapAny::new(Arc::new(init_environment()))
         })
         .load_full();