Fixed a potential concurrency issue when reloading configuration (#1108)

Signed-off-by: dhoard <doug.hoard@gmail.com>
prometheus · Dec 27, 2024 · cb88d2f · cb88d2f
1 parent 9f1fdec
commit cb88d2f
Showing 1 changed file with 5 additions and 4 deletions.
diff --git a/collector/src/main/java/io/prometheus/jmx/JmxCollector.java b/collector/src/main/java/io/prometheus/jmx/JmxCollector.java
@@ -229,8 +229,9 @@ private void exitOnConfigError() {
     private void reloadConfig() {
         try (FileReader fr = new FileReader(configFile)) {
             Map<String, Object> newYamlConfig = new Yaml().load(fr);
-            config = loadConfig(newYamlConfig);
-            config.lastUpdate = configFile.lastModified();
+            Config newConfig = loadConfig(newYamlConfig);
+            newConfig.lastUpdate = configFile.lastModified();
+            config = newConfig;
             configReloadSuccess.inc();
         } catch (Exception e) {
             LOGGER.log(SEVERE, "Configuration reload failed: %s: ", e);
@@ -240,8 +241,8 @@ private void reloadConfig() {
 
     private synchronized Config getLatestConfig() {
         if (configFile != null) {
-            long mtime = configFile.lastModified();
-            if (mtime > config.lastUpdate) {
+            long lastModified = configFile.lastModified();
+            if (lastModified > config.lastUpdate) {
                 LOGGER.log(FINE, "Configuration file changed, reloading...");
                 reloadConfig();
             }