From 030c8c464801d0706bb7004312ed3f54f6a144a1 Mon Sep 17 00:00:00 2001
From: Harald Musum <musum@yahooinc.com>
Date: Mon, 20 Jun 2022 23:23:12 +0200
Subject: Synchronize access to sessionStateWatchers map

---
 .../config/server/session/SessionRepository.java   | 26 ++++++++++++++--------
 1 file changed, 17 insertions(+), 9 deletions(-)

(limited to 'configserver')

diff --git a/configserver/src/main/java/com/yahoo/vespa/config/server/session/SessionRepository.java b/configserver/src/main/java/com/yahoo/vespa/config/server/session/SessionRepository.java
index 059d192e7d2..9b8abbf4cf6 100644
--- a/configserver/src/main/java/com/yahoo/vespa/config/server/session/SessionRepository.java
+++ b/configserver/src/main/java/com/yahoo/vespa/config/server/session/SessionRepository.java
@@ -315,7 +315,7 @@ public class SessionRepository {
     public void deleteLocalSession(LocalSession session) {
         long sessionId = session.getSessionId();
         log.log(Level.FINE, () -> "Deleting local session " + sessionId);
-        SessionStateWatcher watcher = sessionStateWatchers.remove(sessionId);
+        SessionStateWatcher watcher = removeSessionStateWatcher(sessionId);
         if (watcher != null) watcher.close();
         localSessionCache.remove(sessionId);
         NestedTransaction transaction = new NestedTransaction();
@@ -323,6 +323,12 @@ public class SessionRepository {
         transaction.commit();
     }
 
+    private SessionStateWatcher removeSessionStateWatcher(long sessionId) {
+        synchronized (sessionStateWatchers) {
+            return sessionStateWatchers.remove(sessionId);
+        }
+    }
+
     private void deleteAllSessions() {
         for (LocalSession session : getLocalSessions()) {
             deleteLocalSession(session);
@@ -886,13 +892,15 @@ public class SessionRepository {
     }
 
     private void updateSessionStateWatcher(long sessionId, RemoteSession remoteSession) {
-        SessionStateWatcher sessionStateWatcher = sessionStateWatchers.get(sessionId);
-        if (sessionStateWatcher == null) {
-            Curator.FileCache fileCache = curator.createFileCache(getSessionStatePath(sessionId).getAbsolute(), false);
-            fileCache.addListener(this::nodeChanged);
-            sessionStateWatchers.put(sessionId, new SessionStateWatcher(fileCache, remoteSession, metricUpdater, zkWatcherExecutor, this));
-        } else {
-            sessionStateWatcher.updateRemoteSession(remoteSession);
+        synchronized (sessionStateWatchers) {
+            SessionStateWatcher sessionStateWatcher = sessionStateWatchers.get(sessionId);
+            if (sessionStateWatcher == null) {
+                Curator.FileCache fileCache = curator.createFileCache(getSessionStatePath(sessionId).getAbsolute(), false);
+                fileCache.addListener(this::nodeChanged);
+                sessionStateWatchers.put(sessionId, new SessionStateWatcher(fileCache, remoteSession, metricUpdater, zkWatcherExecutor, this));
+            } else {
+                sessionStateWatcher.updateRemoteSession(remoteSession);
+            }
         }
     }
 
@@ -928,7 +936,7 @@ public class SessionRepository {
             long sessionId = it.next().sessionId;
             if (existingSessions.contains(sessionId)) continue;
 
-            SessionStateWatcher watcher = sessionStateWatchers.remove(sessionId);
+            SessionStateWatcher watcher = removeSessionStateWatcher(sessionId);
             if (watcher != null) watcher.close();
             it.remove();
             metricUpdater.incRemovedSessions();
-- 
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