From 012df197811ac43b4daedd3f20150bd4bd28e125 Mon Sep 17 00:00:00 2001
From: Eduwer Camacaro <eduwerc@gmail.com>
Date: Fri, 21 Feb 2025 09:08:36 -0500
Subject: [PATCH] fix(server): make standby on instance tracker synchronized
 for multiple threads

---
 .../server/monitoring/StandbyStoresOnInstance.java     | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/server/src/main/java/io/littlehorse/server/monitoring/StandbyStoresOnInstance.java b/server/src/main/java/io/littlehorse/server/monitoring/StandbyStoresOnInstance.java
index 5aba1dd05..3a81e711c 100644
--- a/server/src/main/java/io/littlehorse/server/monitoring/StandbyStoresOnInstance.java
+++ b/server/src/main/java/io/littlehorse/server/monitoring/StandbyStoresOnInstance.java
@@ -32,7 +32,7 @@ public final class StandbyStoresOnInstance {
      * @param currentOffset batch end offset
      * @param endOffset topic partition end offset
      */
-    public void recordOffsets(TopicPartition topicPartition, final long currentOffset, final long endOffset) {
+    public synchronized void recordOffsets(TopicPartition topicPartition, final long currentOffset, final long endOffset) {
         StandbyTopicPartitionMetrics newMetric =
                 new StandbyTopicPartitionMetrics(topicPartition, currentOffset, endOffset);
         partitions.remove(newMetric);
@@ -43,7 +43,7 @@ public void recordOffsets(TopicPartition topicPartition, final long currentOffse
      * Calculates the total lag across all partitions in the store
      * @return sum of lag values for all partitions.
      */
-    public long totalLag() {
+    public synchronized long totalLag() {
         return partitions.stream()
                 .map(StandbyTopicPartitionMetrics::getCurrentLag)
                 .map(lag -> Math.max(0, lag)) // ignore sentinel values (-1)
@@ -56,11 +56,11 @@ public long totalLag() {
      *
      * @return The number of registered partitions for this store.
      */
-    public int registeredPartitions() {
+    public synchronized int registeredPartitions() {
         return partitions.size();
     }
 
-    public Optional<StandbyTopicPartitionMetrics> lagInfoForPartition(int partition) {
+    public synchronized Optional<StandbyTopicPartitionMetrics> lagInfoForPartition(int partition) {
         return partitions.stream()
                 .filter(standbyTopicPartitionMetrics -> standbyTopicPartitionMetrics.getPartition() == partition)
                 .findFirst();
@@ -73,7 +73,7 @@ public Optional<StandbyTopicPartitionMetrics> lagInfoForPartition(int partition)
      * @param endOffset partition end offset
      * @param reason standby suspension reason
      */
-    public void suspendPartition(
+    public synchronized void suspendPartition(
             final TopicPartition topicPartition,
             final long currentOffset,
             final long endOffset,