From 53e91737573a40b0479062316baae2d234811228 Mon Sep 17 00:00:00 2001
From: Christian Schwarz <christian@neon.tech>
Date: Fri, 22 Mar 2024 22:57:53 +0000
Subject: [PATCH] Revert "use tokio::signal for pageserver shutdown"

This reverts commit b5460314806e826b95ae8f8a8214d4fb4287e50c.
---
 pageserver/src/bin/pageserver.rs | 62 ++++++++++++++++----------------
 1 file changed, 32 insertions(+), 30 deletions(-)

diff --git a/pageserver/src/bin/pageserver.rs b/pageserver/src/bin/pageserver.rs
index f1a03471bb..21f86eba3d 100644
--- a/pageserver/src/bin/pageserver.rs
+++ b/pageserver/src/bin/pageserver.rs
@@ -17,7 +17,6 @@ use pageserver::disk_usage_eviction_task::{self, launch_disk_usage_global_evicti
 use pageserver::metrics::{STARTUP_DURATION, STARTUP_IS_LOADING};
 use pageserver::tenant::{secondary, TenantSharedResources};
 use remote_storage::GenericRemoteStorage;
-use tokio::signal::unix::SignalKind;
 use tokio::time::Instant;
 use tracing::*;
 
@@ -663,37 +662,40 @@ fn start_pageserver(
     let mut shutdown_pageserver = Some(shutdown_pageserver.drop_guard());
 
     // All started up! Now just sit and wait for shutdown signal.
-
     {
-        THE_RUNTIME.block_on(async move {
-            let mut sigint = tokio::signal::unix::signal(SignalKind::interrupt()).unwrap();
-            let mut sigterm = tokio::signal::unix::signal(SignalKind::terminate()).unwrap();
-            let mut sigquit = tokio::signal::unix::signal(SignalKind::quit()).unwrap();
-            let signal = tokio::select! {
-                _ = sigquit.recv() => {
-                    info!("Got signal SIGQUIT. Terminating in immediate shutdown mode",);
-                    std::process::exit(111);
-                }
-                _ = sigint.recv() => { "SIGINT" },
-                _ = sigterm.recv() => { "SIGTERM" },
-            };
+        use signal_hook::consts::*;
+        let signal_handler = THE_RUNTIME.spawn_blocking(move || {
+            let mut signals =
+                signal_hook::iterator::Signals::new([SIGINT, SIGTERM, SIGQUIT]).unwrap();
+            return signals
+                .forever()
+                .next()
+                .expect("forever() never returns None unless explicitly closed");
+        });
+        let signal = THE_RUNTIME.block_on(signal_handler).expect("join error");
+        match signal {
+            SIGQUIT => {
+                info!("Got signal {signal}. Terminating in immediate shutdown mode",);
+                std::process::exit(111);
+            }
+            SIGINT | SIGTERM => {
+                info!("Got signal {signal}. Terminating gracefully in fast shutdown mode",);
 
-            info!("Got signal {signal}. Terminating gracefully in fast shutdown mode",);
-
-            // This cancels the `shutdown_pageserver` cancellation tree.
-            // Right now that tree doesn't reach very far, and `task_mgr` is used instead.
-            // The plan is to change that over time.
-            shutdown_pageserver.take();
-            let bg_remote_storage = remote_storage.clone();
-            let bg_deletion_queue = deletion_queue.clone();
-            pageserver::shutdown_pageserver(
-                &tenant_manager,
-                bg_remote_storage.map(|_| bg_deletion_queue),
-                0,
-            )
-            .await;
-            unreachable!()
-        })
+                // This cancels the `shutdown_pageserver` cancellation tree.
+                // Right now that tree doesn't reach very far, and `task_mgr` is used instead.
+                // The plan is to change that over time.
+                shutdown_pageserver.take();
+                let bg_remote_storage = remote_storage.clone();
+                let bg_deletion_queue = deletion_queue.clone();
+                THE_RUNTIME.block_on(pageserver::shutdown_pageserver(
+                    &tenant_manager,
+                    bg_remote_storage.map(|_| bg_deletion_queue),
+                    0,
+                ));
+                unreachable!()
+            }
+            _ => unreachable!(),
+        }
     }
 }