Make NodeEnvironment.nodeDataPaths singular (#72432)

This commit renames the nodeDataPaths method to be singular and return a
single Path instead of an array. This is done in isolation from other
NodeEnvironemnt methods to make it reviewable.

relates #71205

server/src/internalClusterTest/java/org/elasticsearch/cluster/coordination/UnsafeBootstrapAndDetachCommandIT.java

@@ -156,7 +156,7 @@ public void testBootstrapNoClusterState() throws IOException {
         internalCluster().stopRandomDataNode();
         Environment environment = TestEnvironment.newEnvironment(
             Settings.builder().put(internalCluster().getDefaultSettings()).put(dataPathSettings).build());
-        PersistedClusterStateService.deleteAll(nodeEnvironment.nodeDataPaths());
+        PersistedClusterStateService.deleteAll(nodeEnvironment.nodeDataPath());
 
         expectThrows(() -> unsafeBootstrap(environment), ElasticsearchNodeCommand.NO_NODE_METADATA_FOUND_MSG);
     }
@@ -170,7 +170,7 @@ public void testDetachNoClusterState() throws IOException {
         internalCluster().stopRandomDataNode();
         Environment environment = TestEnvironment.newEnvironment(
             Settings.builder().put(internalCluster().getDefaultSettings()).put(dataPathSettings).build());
-        PersistedClusterStateService.deleteAll(nodeEnvironment.nodeDataPaths());
+        PersistedClusterStateService.deleteAll(nodeEnvironment.nodeDataPath());
 
         expectThrows(() -> detachCluster(environment), ElasticsearchNodeCommand.NO_NODE_METADATA_FOUND_MSG);
     }
@@ -252,7 +252,7 @@ public void test3MasterNodes2Failed() throws Exception {
 
         logger.info("--> unsafely-bootstrap 1st master-eligible node");
         MockTerminal terminal = unsafeBootstrap(environmentMaster1);
-        Metadata metadata = ElasticsearchNodeCommand.createPersistedClusterStateService(Settings.EMPTY, nodeEnvironment.nodeDataPaths())
+        Metadata metadata = ElasticsearchNodeCommand.createPersistedClusterStateService(Settings.EMPTY, nodeEnvironment.nodeDataPath())
             .loadBestOnDiskState().metadata;
         assertThat(terminal.getOutput(), containsString(
             String.format(Locale.ROOT, UnsafeBootstrapMasterCommand.CLUSTER_STATE_TERM_VERSION_MSG_FORMAT,

server/src/internalClusterTest/java/org/elasticsearch/env/NodeEnvironmentIT.java

@@ -95,15 +95,15 @@ public Settings onNodeStopped(String nodeName) {
         assertThat(ex.getMessage(), startsWith("node does not have the data role but has shard data"));
     }
 
-    private IllegalStateException expectThrowsOnRestart(CheckedConsumer<Path[], Exception> onNodeStopped) {
+    private IllegalStateException expectThrowsOnRestart(CheckedConsumer<Path, Exception> onNodeStopped) {
         internalCluster().startNode();
-        final Path[] dataPaths = internalCluster().getInstance(NodeEnvironment.class).nodeDataPaths();
+        final Path dataPath = internalCluster().getInstance(NodeEnvironment.class).nodeDataPath();
         return expectThrows(IllegalStateException.class,
             () -> internalCluster().restartRandomDataNode(new InternalTestCluster.RestartCallback() {
                 @Override
                 public Settings onNodeStopped(String nodeName) {
                     try {
-                        onNodeStopped.accept(dataPaths);
+                        onNodeStopped.accept(dataPath);
                     } catch (Exception e) {
                         throw new AssertionError(e);
                     }

server/src/internalClusterTest/java/org/elasticsearch/gateway/GatewayIndexStateIT.java

@@ -513,20 +513,18 @@ public void testHalfDeletedIndexImport() throws Exception {
         ensureGreen("test");
 
         final Metadata metadata = internalCluster().getInstance(ClusterService.class).state().metadata();
-        final Path[] paths = internalCluster().getInstance(NodeEnvironment.class).nodeDataPaths();
+        final Path path = internalCluster().getInstance(NodeEnvironment.class).nodeDataPath();
         final String nodeId = client().admin().cluster().prepareNodesInfo(nodeName).clear().get().getNodes().get(0).getNode().getId();
 
         writeBrokenMeta(metaStateService -> {
-            for (final Path path : paths) {
-                IOUtils.rm(path.resolve(PersistedClusterStateService.METADATA_DIRECTORY_NAME));
-            }
+            IOUtils.rm(path.resolve(PersistedClusterStateService.METADATA_DIRECTORY_NAME));
             metaStateService.writeGlobalState("test", Metadata.builder(metadata)
                 // we remove the manifest file, resetting the term and making this look like an upgrade from 6.x, so must also reset the
                 // term in the coordination metadata
                 .coordinationMetadata(CoordinationMetadata.builder(metadata.coordinationMetadata()).term(0L).build())
                 // add a tombstone but do not delete the index metadata from disk
                .putCustom(IndexGraveyard.TYPE, IndexGraveyard.builder().addTombstone(metadata.index("test").getIndex()).build()).build());
-            NodeMetadata.FORMAT.writeAndCleanup(new NodeMetadata(nodeId, Version.CURRENT), paths);
+            NodeMetadata.FORMAT.writeAndCleanup(new NodeMetadata(nodeId, Version.CURRENT), path);
         });
 
         ensureGreen();

server/src/main/java/org/elasticsearch/cluster/coordination/ElasticsearchNodeCommand.java

@@ -101,7 +101,7 @@ public ElasticsearchNodeCommand(String description) {
         super(description);
     }
 
-    public static PersistedClusterStateService createPersistedClusterStateService(Settings settings, Path[] dataPaths) throws IOException {
+    public static PersistedClusterStateService createPersistedClusterStateService(Settings settings, Path... dataPaths) throws IOException {
         final NodeMetadata nodeMetadata = PersistedClusterStateService.nodeMetadata(dataPaths);
         if (nodeMetadata == null) {
             throw new ElasticsearchException(NO_NODE_METADATA_FOUND_MSG);

server/src/main/java/org/elasticsearch/env/NodeEnvironment.java

@@ -894,13 +894,9 @@ public boolean hasNodeFile() {
      * Returns an array of all of the nodes data locations.
      * @throws IllegalStateException if the node is not configured to store local locations
      */
-    public Path[] nodeDataPaths() {
+    public Path nodeDataPath() {
         assertEnvIsLocked();
-        Path[] paths = new Path[nodePaths.length];
-        for(int i=0;i<paths.length;i++) {
-            paths[i] = nodePaths[i].path;
-        }
-        return paths;
+        return nodePaths[0].path;
     }
 
     /**
@@ -1295,9 +1291,7 @@ public static Path shardStatePathToDataPath(Path shardPath) {
      * This prevents disasters if nodes are started under the wrong username etc.
      */
     private void assertCanWrite() throws IOException {
-        for (Path path : nodeDataPaths()) { // check node-paths are writable
-            tryWriteTempFile(path);
-        }
+        tryWriteTempFile(nodeDataPath());
         for (String indexFolderName : this.availableIndexFolders()) {
             for (Path indexPath : this.resolveIndexFolder(indexFolderName)) { // check index paths are writable
                 Path indexStatePath = indexPath.resolve(MetadataStateFormat.STATE_DIR_NAME);

server/src/main/java/org/elasticsearch/gateway/MetaStateService.java

@@ -58,7 +58,7 @@ public MetaStateService(NodeEnvironment nodeEnv, NamedXContentRegistry namedXCon
      * @throws IOException if some IOException when loading files occurs or there is no metadata referenced by manifest file.
      */
     public Tuple<Manifest, Metadata> loadFullState() throws IOException {
-        final Manifest manifest = MANIFEST_FORMAT.loadLatestState(logger, namedXContentRegistry, nodeEnv.nodeDataPaths());
+        final Manifest manifest = MANIFEST_FORMAT.loadLatestState(logger, namedXContentRegistry, nodeEnv.nodeDataPath());
         if (manifest == null) {
             return loadFullStateBWC();
         }
@@ -68,7 +68,7 @@ public Tuple<Manifest, Metadata> loadFullState() throws IOException {
             metadataBuilder = Metadata.builder();
         } else {
             final Metadata globalMetadata = METADATA_FORMAT.loadGeneration(logger, namedXContentRegistry, manifest.getGlobalGeneration(),
-                    nodeEnv.nodeDataPaths());
+                    nodeEnv.nodeDataPath());
             if (globalMetadata != null) {
                 metadataBuilder = Metadata.builder(globalMetadata);
             } else {
@@ -101,7 +101,7 @@ private Tuple<Manifest, Metadata> loadFullStateBWC() throws IOException {
         Metadata.Builder metadataBuilder;
 
         Tuple<Metadata, Long> metadataAndGeneration =
-                METADATA_FORMAT.loadLatestStateWithGeneration(logger, namedXContentRegistry, nodeEnv.nodeDataPaths());
+                METADATA_FORMAT.loadLatestStateWithGeneration(logger, namedXContentRegistry, nodeEnv.nodeDataPath());
         Metadata globalMetadata = metadataAndGeneration.v1();
         long globalStateGeneration = metadataAndGeneration.v2();
 
@@ -173,7 +173,7 @@ List<IndexMetadata> loadIndicesStates(Predicate<String> excludeIndexPathIdsPredi
      * Loads the global state, *without* index state, see {@link #loadFullState()} for that.
      */
     Metadata loadGlobalState() throws IOException {
-        return METADATA_FORMAT.loadLatestState(logger, namedXContentRegistry, nodeEnv.nodeDataPaths());
+        return METADATA_FORMAT.loadLatestState(logger, namedXContentRegistry, nodeEnv.nodeDataPath());
     }
 
     /**
@@ -185,7 +185,7 @@ Metadata loadGlobalState() throws IOException {
     public void writeManifestAndCleanup(String reason, Manifest manifest) throws WriteStateException {
         logger.trace("[_meta] writing state, reason [{}]", reason);
         try {
-            long generation = MANIFEST_FORMAT.writeAndCleanup(manifest, nodeEnv.nodeDataPaths());
+            long generation = MANIFEST_FORMAT.writeAndCleanup(manifest, nodeEnv.nodeDataPath());
             logger.trace("[_meta] state written (generation: {})", generation);
         } catch (WriteStateException ex) {
             throw new WriteStateException(ex.isDirty(), "[_meta]: failed to write meta state", ex);
@@ -222,7 +222,7 @@ public long writeIndex(String reason, IndexMetadata indexMetadata) throws WriteS
     long writeGlobalState(String reason, Metadata metadata) throws WriteStateException {
         logger.trace("[_global] writing state, reason [{}]", reason);
         try {
-            long generation = METADATA_FORMAT.write(metadata, nodeEnv.nodeDataPaths());
+            long generation = METADATA_FORMAT.write(metadata, nodeEnv.nodeDataPath());
             logger.trace("[_global] state written");
             return generation;
         } catch (WriteStateException ex) {
@@ -236,7 +236,7 @@ long writeGlobalState(String reason, Metadata metadata) throws WriteStateExcepti
      * @param currentGeneration current state generation to keep in the directory.
      */
     void cleanupGlobalState(long currentGeneration) {
-        METADATA_FORMAT.cleanupOldFiles(currentGeneration, nodeEnv.nodeDataPaths());
+        METADATA_FORMAT.cleanupOldFiles(currentGeneration, nodeEnv.nodeDataPath());
     }
 
     /**
@@ -254,8 +254,8 @@ public void cleanupIndex(Index index, long currentGeneration) {
      * (only used for dangling indices at that point).
      */
     public void unreferenceAll() throws IOException {
-        MANIFEST_FORMAT.writeAndCleanup(Manifest.empty(), nodeEnv.nodeDataPaths()); // write empty file so that indices become unreferenced
-        METADATA_FORMAT.cleanupOldFiles(Long.MAX_VALUE, nodeEnv.nodeDataPaths());
+        MANIFEST_FORMAT.writeAndCleanup(Manifest.empty(), nodeEnv.nodeDataPath()); // write empty file so that indices become unreferenced
+        METADATA_FORMAT.cleanupOldFiles(Long.MAX_VALUE, nodeEnv.nodeDataPath());
     }
 
     /**
@@ -270,6 +270,6 @@ public void deleteAll() throws IOException {
             // delete meta state directories of indices
             MetadataStateFormat.deleteMetaState(nodeEnv.resolveIndexFolder(indexFolderName));
         }
-        MANIFEST_FORMAT.cleanupOldFiles(Long.MAX_VALUE, nodeEnv.nodeDataPaths()); // finally delete manifest
+        MANIFEST_FORMAT.cleanupOldFiles(Long.MAX_VALUE, nodeEnv.nodeDataPath()); // finally delete manifest
     }
 }

server/src/main/java/org/elasticsearch/gateway/PersistedClusterStateService.java

@@ -136,7 +136,7 @@ public class PersistedClusterStateService {
 
     public PersistedClusterStateService(NodeEnvironment nodeEnvironment, NamedXContentRegistry namedXContentRegistry, BigArrays bigArrays,
                                         ClusterSettings clusterSettings, LongSupplier relativeTimeMillisSupplier) {
-        this(nodeEnvironment.nodeDataPaths(), nodeEnvironment.nodeId(), namedXContentRegistry, bigArrays, clusterSettings,
+        this(new Path[] { nodeEnvironment.nodeDataPath() }, nodeEnvironment.nodeId(), namedXContentRegistry, bigArrays, clusterSettings,
             relativeTimeMillisSupplier);
     }
 
@@ -202,7 +202,7 @@ private static IndexWriter createIndexWriter(Directory directory, boolean openEx
      * Remove all persisted cluster states from the given data paths, for use in tests. Should only be called when there is no open
      * {@link Writer} on these paths.
      */
-    public static void deleteAll(Path[] dataPaths) throws IOException {
+    public static void deleteAll(Path... dataPaths) throws IOException {
         for (Path dataPath : dataPaths) {
             Lucene.cleanLuceneIndex(new SimpleFSDirectory(dataPath.resolve(METADATA_DIRECTORY_NAME)));
         }

server/src/main/java/org/elasticsearch/monitor/fs/FsHealthService.java

@@ -30,7 +30,6 @@
 import java.nio.file.Files;
 import java.nio.file.Path;
 import java.nio.file.StandardOpenOption;
-import java.util.HashSet;
 import java.util.Set;
 import java.util.function.LongSupplier;
 import java.util.stream.Collectors;
@@ -141,43 +140,38 @@ public void run() {
         }
 
         private void monitorFSHealth() {
-            Set<Path> currentUnhealthyPaths = null;
-            Path[] paths = null;
+            Path path;
             try {
-                paths = nodeEnv.nodeDataPaths();
+                path = nodeEnv.nodeDataPath();
             } catch (IllegalStateException e) {
                 logger.error("health check failed", e);
                 brokenLock = true;
                 return;
             }
 
-            for (Path path : paths) {
-                long executionStartTime = currentTimeMillisSupplier.getAsLong();
-                try {
-                    if (Files.exists(path)) {
-                        Path tempDataPath = path.resolve(TEMP_FILE_NAME);
-                        Files.deleteIfExists(tempDataPath);
-                        try (OutputStream os = Files.newOutputStream(tempDataPath, StandardOpenOption.CREATE_NEW)) {
-                            os.write(byteToWrite);
-                            IOUtils.fsync(tempDataPath, false);
-                        }
-                        Files.delete(tempDataPath);
-                        final long elapsedTime = currentTimeMillisSupplier.getAsLong() - executionStartTime;
-                        if (elapsedTime > slowPathLoggingThreshold.millis()) {
-                            logger.warn("health check of [{}] took [{}ms] which is above the warn threshold of [{}]",
-                                path, elapsedTime, slowPathLoggingThreshold);
-                        }
+            brokenLock = false;
+            long executionStartTime = currentTimeMillisSupplier.getAsLong();
+            try {
+                if (Files.exists(path)) {
+                    Path tempDataPath = path.resolve(TEMP_FILE_NAME);
+                    Files.deleteIfExists(tempDataPath);
+                    try (OutputStream os = Files.newOutputStream(tempDataPath, StandardOpenOption.CREATE_NEW)) {
+                        os.write(byteToWrite);
+                        IOUtils.fsync(tempDataPath, false);
                     }
-                } catch (Exception ex) {
-                    logger.error(new ParameterizedMessage("health check of [{}] failed", path), ex);
-                    if (currentUnhealthyPaths == null) {
-                        currentUnhealthyPaths = new HashSet<>(1);
+                    Files.delete(tempDataPath);
+                    final long elapsedTime = currentTimeMillisSupplier.getAsLong() - executionStartTime;
+                    if (elapsedTime > slowPathLoggingThreshold.millis()) {
+                        logger.warn("health check of [{}] took [{}ms] which is above the warn threshold of [{}]",
+                            path, elapsedTime, slowPathLoggingThreshold);
                     }
-                    currentUnhealthyPaths.add(path);
                 }
+            } catch (Exception ex) {
+                logger.error(new ParameterizedMessage("health check of [{}] failed", path), ex);
+                unhealthyPaths = Set.of(path);
+                return;
             }
-            unhealthyPaths = currentUnhealthyPaths;
-            brokenLock = false;
+            unhealthyPaths = null;
         }
     }
 }

server/src/main/java/org/elasticsearch/node/Node.java

@@ -814,7 +814,7 @@ public Node start() throws NodeValidationException {
             try {
                 assert injector.getInstance(MetaStateService.class).loadFullState().v1().isEmpty();
                 final NodeMetadata nodeMetadata = NodeMetadata.FORMAT.loadLatestState(logger, NamedXContentRegistry.EMPTY,
-                    nodeEnvironment.nodeDataPaths());
+                    nodeEnvironment.nodeDataPath());
                 assert nodeMetadata != null;
                 assert nodeMetadata.nodeVersion().equals(Version.CURRENT);
                 assert nodeMetadata.nodeId().equals(localNodeFactory.getNode().getId());

server/src/test/java/org/elasticsearch/env/NodeEnvironmentTests.java

@@ -62,7 +62,7 @@ public void testNodeLock() throws IOException {
         // Close the environment that holds the lock and make sure we can get the lock after release
         env.close();
         env = new NodeEnvironment(settings, TestEnvironment.newEnvironment(settings));
-        assertThat(env.nodeDataPaths()[0], equalTo(PathUtils.get(dataPath)));
+        assertThat(env.nodeDataPath(), equalTo(PathUtils.get(dataPath)));
 
         env.close();
         assertThat(env.lockedShards(), empty());

server/src/test/java/org/elasticsearch/env/NodeRepurposeCommandTests.java

@@ -61,7 +61,7 @@ public void createNodePaths() throws IOException {
         dataMasterSettings = buildEnvSettings(Settings.EMPTY);
         environment = TestEnvironment.newEnvironment(dataMasterSettings);
         try (NodeEnvironment nodeEnvironment = new NodeEnvironment(dataMasterSettings, environment)) {
-            nodePaths = nodeEnvironment.nodeDataPaths();
+            nodePaths = new Path[] { nodeEnvironment.nodeDataPath() };
             final String nodeId = randomAlphaOfLength(10);
             try (PersistedClusterStateService.Writer writer = new PersistedClusterStateService(nodePaths, nodeId,
                 xContentRegistry(), BigArrays.NON_RECYCLING_INSTANCE,
@@ -89,7 +89,7 @@ public void testNothingToCleanup() throws Exception {
         if (randomBoolean()) {
             try (NodeEnvironment env = new NodeEnvironment(noDataMasterSettings, environment)) {
                 try (PersistedClusterStateService.Writer writer =
-                         ElasticsearchNodeCommand.createPersistedClusterStateService(Settings.EMPTY, env.nodeDataPaths()).createWriter()) {
+                         ElasticsearchNodeCommand.createPersistedClusterStateService(Settings.EMPTY, env.nodeDataPath()).createWriter()) {
                     writer.writeFullStateAndCommit(1L, ClusterState.EMPTY_STATE);
                 }
             }
@@ -217,7 +217,7 @@ private void createIndexDataFiles(Settings settings, int shardCount, boolean wri
         try (NodeEnvironment env = new NodeEnvironment(settings, environment)) {
             if (writeClusterState) {
                 try (PersistedClusterStateService.Writer writer =
-                         ElasticsearchNodeCommand.createPersistedClusterStateService(Settings.EMPTY, env.nodeDataPaths()).createWriter()) {
+                         ElasticsearchNodeCommand.createPersistedClusterStateService(Settings.EMPTY, env.nodeDataPath()).createWriter()) {
                     writer.writeFullStateAndCommit(1L, ClusterState.builder(ClusterName.DEFAULT)
                         .metadata(Metadata.builder().put(IndexMetadata.builder(INDEX.getName())
                             .settings(Settings.builder().put("index.version.created", Version.CURRENT)

server/src/test/java/org/elasticsearch/env/OverrideNodeVersionCommandTests.java

@@ -42,7 +42,7 @@ public void createNodePaths() throws IOException {
         final Settings settings = buildEnvSettings(Settings.EMPTY);
         environment = TestEnvironment.newEnvironment(settings);
         try (NodeEnvironment nodeEnvironment = new NodeEnvironment(settings, environment)) {
-            nodePaths = nodeEnvironment.nodeDataPaths();
+            nodePaths = new Path[] { nodeEnvironment.nodeDataPath() };
             nodeId = nodeEnvironment.nodeId();
 
             try (PersistedClusterStateService.Writer writer = new PersistedClusterStateService(nodePaths, nodeId,