Add fix

Author: jfreden

server/src/internalClusterTest/java/org/elasticsearch/reservedstate/service/FileSettingsServiceIT.java

@@ -522,28 +522,30 @@ public void testSymlinkUpdateTriggerReload() throws Exception {
             assertBusy(() -> assertTrue(masterFileSettingsService.watching()));
             assertFalse(dataFileSettingsService.watching());
 
-            createK8sLikeMount(masterNode);
+            // Create the settings.json as a symlink to simulate k8 setup
+            // settings.json -> ..data/settings.json
+            // ..data -> ..TIMESTAMP_TEMP_FOLDER_1
+            createK8sLikeSymlinks(masterNode);
             assertClusterStateSaveOK(savedClusterState.v1(), savedClusterState.v2(), "50mb");
         }
         {
             var savedClusterState = setupClusterStateListener(masterNode);
-            updateSymbolicLink(masterNode, testJSON43mb);
+            // Update ..data symlink to ..data -> ..TIMESTAMP_TEMP_FOLDER_2 to simulate kubernetes secret update
+            updateSymlinks(masterNode, testJSON43mb);
             assertClusterStateSaveOK(savedClusterState.v1(), savedClusterState.v2(), "43mb");
         }
     }
 
-    public Path createK8sLikeMount(String node) throws Exception {
+    public Path createK8sLikeSymlinks(String node) throws Exception {
         FileSettingsService fileSettingsService = internalCluster().getInstance(FileSettingsService.class, node);
         Path baseDir = fileSettingsService.watchedFileDir();
         var fileDir = Files.createDirectories(baseDir.resolve("..TIMESTAMP_TEMP_FOLDER_1"));
         writeJSONFile(node, testJSON, logger, versionCounter.incrementAndGet(), fileDir.resolve("settings.json"));
-
         var dataDir = Files.createSymbolicLink(baseDir.resolve("..data"), fileDir.getFileName());
-
         return Files.createSymbolicLink(baseDir.resolve("settings.json"), dataDir.getFileName().resolve("settings.json"));
     }
 
-    public void updateSymbolicLink(String node, String json) throws Exception {
+    public void updateSymlinks(String node, String json) throws Exception {
         FileSettingsService fileSettingsService = internalCluster().getInstance(FileSettingsService.class, node);
         Path baseDir = fileSettingsService.watchedFileDir();
         var fileDir = Files.createDirectories(baseDir.resolve("..TIMESTAMP_TEMP_FOLDER_2"));

server/src/main/java/org/elasticsearch/common/file/AbstractFileWatchingService.java

@@ -18,6 +18,7 @@
 import java.io.IOException;
 import java.io.InputStream;
 import java.nio.file.ClosedWatchServiceException;
+import java.nio.file.Files;
 import java.nio.file.NoSuchFileException;
 import java.nio.file.Path;
 import java.nio.file.StandardWatchEventKinds;
@@ -241,7 +242,9 @@ protected final void watcherThread() {
                     Set<Path> processedFiles = new HashSet<>();
                     for (WatchEvent<?> e : events) {
                         Path fullFile = settingsDir.resolve(e.context().toString());
-                        if (processedFiles.add(fullFile)) {
+                        if (Files.isSymbolicLink(fullFile)) {
+                            reprocessAllChangedFilesInSettingsDir();
+                        } else if (processedFiles.add(fullFile)) {
                             if (fileChanged(fullFile)) {
                                 process(fullFile);
                             }
@@ -257,14 +260,7 @@ protected final void watcherThread() {
                         settingsDirWatchKey = enableDirectoryWatcher(settingsDirWatchKey, settingsDir);
 
                         // re-read the settings directory, and ping for any changes
-                        try (Stream<Path> files = filesList(settingsDir)) {
-                            for (var f = files.iterator(); f.hasNext();) {
-                                Path file = f.next();
-                                if (fileChanged(file)) {
-                                    process(file);
-                                }
-                            }
-                        }
+                        reprocessAllChangedFilesInSettingsDir();
                     } else if (settingsDirWatchKey != null) {
                         settingsDirWatchKey.cancel();
                     }
@@ -279,6 +275,17 @@ protected final void watcherThread() {
         }
     }
 
+    private void reprocessAllChangedFilesInSettingsDir() throws IOException, InterruptedException {
+        try (Stream<Path> files = filesList(settingsDir)) {
+            for (var f = files.iterator(); f.hasNext();) {
+                Path file = f.next();
+                if (fileChanged(file)) {
+                    process(file);
+                }
+            }
+        }
+    }
+
     protected final synchronized void stopWatcher() {
         if (watching()) {
             logger.debug("stopping watcher ...");