fc-queue-runner: use LISTEN/NOTIFY for reactive wakeups

Signed-off-by: NotAShelf <raf@notashelf.dev>
Change-Id: I3b6f0f5eff05caf7a04a9da7de8b558f6a6a6964

crates/queue-runner/src/main.rs

@@ -68,8 +68,15 @@ async fn main() -> anyhow::Result<()> {
 
   let worker_pool_for_drain = worker_pool.clone();
 
+  let wakeup = Arc::new(tokio::sync::Notify::new());
+  let listener_handle = fc_common::pg_notify::spawn_listener(
+    db.pool(),
+    &[fc_common::pg_notify::CHANNEL_BUILDS_CHANGED],
+    wakeup.clone(),
+  );
+
   tokio::select! {
-      result = fc_queue_runner::runner_loop::run(db.pool().clone(), worker_pool, poll_interval) => {
+      result = fc_queue_runner::runner_loop::run(db.pool().clone(), worker_pool, poll_interval, wakeup) => {
           if let Err(e) = result {
               tracing::error!("Runner loop failed: {e}");
           }
@@ -83,6 +90,9 @@ async fn main() -> anyhow::Result<()> {
       }
   }
 
+  listener_handle.abort();
+  let _ = listener_handle.await;
+
   tracing::info!("Queue runner shutting down, closing database pool");
   db.close().await;
 

crates/queue-runner/src/runner_loop.rs

@@ -5,6 +5,7 @@ use fc_common::{
   repo,
 };
 use sqlx::PgPool;
+use tokio::sync::Notify;
 
 use crate::worker::WorkerPool;
 
@@ -12,6 +13,7 @@ pub async fn run(
   pool: PgPool,
   worker_pool: Arc<WorkerPool>,
   poll_interval: Duration,
+  wakeup: Arc<Notify>,
 ) -> anyhow::Result<()> {
   // Reset orphaned builds from previous crashes (older than 5 minutes)
   match repo::builds::reset_orphaned(&pool, 300).await {
@@ -185,6 +187,7 @@ pub async fn run(
         tracing::error!("Failed to fetch pending builds: {e}");
       },
     }
-    tokio::time::sleep(poll_interval).await;
+    // Wake on NOTIFY or fall back to regular poll interval
+    let _ = tokio::time::timeout(poll_interval, wakeup.notified()).await;
   }
 }