From 53cf4d1baaa994544c02ec12f4bea28598720aa8 Mon Sep 17 00:00:00 2001
From: Alex Auvolat <alex@adnab.me>
Date: Sun, 19 Apr 2020 21:33:38 +0000
Subject: [PATCH] Log which workers are doing what

---
 src/admin_rpc.rs  |  4 +++-
 src/background.rs | 13 +++++++------
 src/block.rs      |  6 ++++--
 src/membership.rs |  4 +++-
 src/table_sync.rs | 14 ++++++++------
 5 files changed, 25 insertions(+), 16 deletions(-)

diff --git a/src/admin_rpc.rs b/src/admin_rpc.rs
index 0318e799..125f897e 100644
--- a/src/admin_rpc.rs
+++ b/src/admin_rpc.rs
@@ -182,7 +182,9 @@ impl AdminRpcHandler {
 			self.garage
 				.system
 				.background
-				.spawn_worker(move |must_exit| async move { self2.repair_worker(must_exit).await })
+				.spawn_worker("Repair worker".into(), move |must_exit| async move {
+					self2.repair_worker(must_exit).await
+				})
 				.await;
 			Ok(AdminRPC::Ok(format!(
 				"Repair launched on {:?}",
diff --git a/src/background.rs b/src/background.rs
index 34e96ff7..b9a4684a 100644
--- a/src/background.rs
+++ b/src/background.rs
@@ -36,8 +36,8 @@ impl BackgroundRunner {
 
 	pub async fn run(self: Arc<Self>) {
 		let mut workers = self.workers.lock().await;
-		for _i in 0..self.n_runners {
-			workers.push(tokio::spawn(self.clone().runner()));
+		for i in 0..self.n_runners {
+			workers.push(tokio::spawn(self.clone().runner(i)));
 		}
 		drop(workers);
 
@@ -68,7 +68,7 @@ impl BackgroundRunner {
 		let _: Result<_, _> = self.queue_in.clone().send((boxed, true));
 	}
 
-	pub async fn spawn_worker<F, T>(&self, worker: F)
+	pub async fn spawn_worker<F, T>(&self, name: String, worker: F)
 	where
 		F: FnOnce(watch::Receiver<bool>) -> T + Send + 'static,
 		T: Future<Output = JobOutput> + Send + 'static,
@@ -77,14 +77,14 @@ impl BackgroundRunner {
 		let stop_signal = self.stop_signal.clone();
 		workers.push(tokio::spawn(async move {
 			if let Err(e) = worker(stop_signal).await {
-				eprintln!("Worker stopped with error: {}", e);
+				eprintln!("Worker stopped with error: {}, error: {}", name, e);
 			} else {
-				println!("A worker exited successfully (which one?)");
+				println!("Worker exited successfully: {}", name);
 			}
 		}));
 	}
 
-	async fn runner(self: Arc<Self>) {
+	async fn runner(self: Arc<Self>, i: usize) {
 		let stop_signal = self.stop_signal.clone();
 		loop {
 			let must_exit: bool = *stop_signal.borrow();
@@ -94,6 +94,7 @@ impl BackgroundRunner {
 				}
 			} else {
 				if must_exit {
+					eprintln!("Background runner {} exiting", i);
 					return;
 				}
 				tokio::time::delay_for(Duration::from_secs(1)).await;
diff --git a/src/block.rs b/src/block.rs
index 11818fd8..81b111ce 100644
--- a/src/block.rs
+++ b/src/block.rs
@@ -107,11 +107,13 @@ impl BlockManager {
 
 	pub async fn spawn_background_worker(self: Arc<Self>) {
 		// Launch 2 simultaneous workers for background resync loop preprocessing
-		for _i in 0..2usize {
+		for i in 0..2usize {
 			let bm2 = self.clone();
 			self.system
 				.background
-				.spawn_worker(move |must_exit| bm2.resync_loop(must_exit))
+				.spawn_worker(format!("block resync worker {}", i), move |must_exit| {
+					bm2.resync_loop(must_exit)
+				})
 				.await;
 		}
 	}
diff --git a/src/membership.rs b/src/membership.rs
index fc21d0b5..193b5936 100644
--- a/src/membership.rs
+++ b/src/membership.rs
@@ -391,7 +391,9 @@ impl System {
 
 		self.clone()
 			.background
-			.spawn_worker(|stop_signal| self.ping_loop(stop_signal).map(Ok))
+			.spawn_worker(format!("ping loop"), |stop_signal| {
+				self.ping_loop(stop_signal).map(Ok)
+			})
 			.await;
 	}
 
diff --git a/src/table_sync.rs b/src/table_sync.rs
index 2fb5de77..a750e04e 100644
--- a/src/table_sync.rs
+++ b/src/table_sync.rs
@@ -96,18 +96,20 @@ where
 		table
 			.system
 			.background
-			.spawn_worker(move |must_exit: watch::Receiver<bool>| {
-				s1.watcher_task(must_exit, busy_rx)
-			})
+			.spawn_worker(
+				format!("table sync watcher for {}", table.name),
+				move |must_exit: watch::Receiver<bool>| s1.watcher_task(must_exit, busy_rx),
+			)
 			.await;
 
 		let s2 = syncer.clone();
 		table
 			.system
 			.background
-			.spawn_worker(move |must_exit: watch::Receiver<bool>| {
-				s2.syncer_task(must_exit, busy_tx)
-			})
+			.spawn_worker(
+				format!("table syncer for {}", table.name),
+				move |must_exit: watch::Receiver<bool>| s2.syncer_task(must_exit, busy_tx),
+			)
 			.await;
 
 		syncer