From d7c8309ccfa5ebc1fc6c7b284cbe74e9a05192a7 Mon Sep 17 00:00:00 2001
From: Bas van Kervel <basvankervel@gmail.com>
Date: Mon, 22 Jul 2024 14:50:09 +0200
Subject: [PATCH] core: extract go routine to separate function

---
 core/node/rpc/sync/client/remote.go | 84 +++++++++++++++--------------
 1 file changed, 44 insertions(+), 40 deletions(-)

diff --git a/core/node/rpc/sync/client/remote.go b/core/node/rpc/sync/client/remote.go
index cce7771f8a..92bd6fcfb0 100644
--- a/core/node/rpc/sync/client/remote.go
+++ b/core/node/rpc/sync/client/remote.go
@@ -93,46 +93,7 @@ func (s *remoteSyncer) Run() {
 
 	latestMsgReceived.Store(time.Now())
 
-	go func() {
-		var (
-			// check every pingTicker if it's time to send a ping req to remote
-			pingTicker = time.NewTicker(3 * time.Second)
-			// don't send a ping req if there was activity within recentActivityInterval
-			recentActivityInterval = 15 * time.Second
-			// if no message was receiving within recentActivityDeadline assume stream is dead
-			recentActivityDeadline = 30 * time.Second
-		)
-		defer pingTicker.Stop()
-
-		for {
-			select {
-			case <-pingTicker.C:
-				now := time.Now()
-				lastMsgRecv := latestMsgReceived.Load().(time.Time)
-				if lastMsgRecv.Add(recentActivityDeadline).Before(now) { // no recent activity -> conn dead
-					s.syncStreamCancel()
-					return
-				}
-
-				if lastMsgRecv.Add(recentActivityInterval).After(now) { // seen recent activity
-					continue
-				}
-
-				// send ping to remote to generate activity to check if remote is still alive
-				if _, err := s.client.PingSync(s.syncStreamCtx, connect.NewRequest(&PingSyncRequest{
-					SyncId: s.syncID,
-					Nonce:  fmt.Sprintf("%d", now.Unix()),
-				})); err != nil {
-					s.syncStreamCancel()
-					return
-				}
-				return
-
-			case <-s.syncStreamCtx.Done():
-				return
-			}
-		}
-	}()
+	go s.connectionAlive(&latestMsgReceived)
 
 	for s.responseStream.Receive() {
 		if s.syncStreamCtx.Err() != nil {
@@ -171,6 +132,49 @@ func (s *remoteSyncer) Run() {
 	}
 }
 
+// connectionAlive periodically pings remote to check if the connection is still alive.
+// if the remote can't be reach the sync stream is canceled.
+func (s *remoteSyncer) connectionAlive(latestMsgReceived *atomic.Value) {
+	var (
+		// check every pingTicker if it's time to send a ping req to remote
+		pingTicker = time.NewTicker(3 * time.Second)
+		// don't send a ping req if there was activity within recentActivityInterval
+		recentActivityInterval = 15 * time.Second
+		// if no message was receiving within recentActivityDeadline assume stream is dead
+		recentActivityDeadline = 30 * time.Second
+	)
+	defer pingTicker.Stop()
+
+	for {
+		select {
+		case <-pingTicker.C:
+			now := time.Now()
+			lastMsgRecv := latestMsgReceived.Load().(time.Time)
+			if lastMsgRecv.Add(recentActivityDeadline).Before(now) { // no recent activity -> conn dead
+				s.syncStreamCancel()
+				return
+			}
+
+			if lastMsgRecv.Add(recentActivityInterval).After(now) { // seen recent activity
+				continue
+			}
+
+			// send ping to remote to generate activity to check if remote is still alive
+			if _, err := s.client.PingSync(s.syncStreamCtx, connect.NewRequest(&PingSyncRequest{
+				SyncId: s.syncID,
+				Nonce:  fmt.Sprintf("%d", now.Unix()),
+			})); err != nil {
+				s.syncStreamCancel()
+				return
+			}
+			return
+
+		case <-s.syncStreamCtx.Done():
+			return
+		}
+	}
+}
+
 func (s *remoteSyncer) Address() common.Address {
 	return s.remoteAddr
 }