Deprecate shared and index data path settings

This commit adds deprecation warnings for use of the path.shared_data
setting as well as the index setting index.data_path.

relates elastic#73168

Author: rjernst

docs/reference/migration/migrate_8_0/settings.asciidoc

@@ -242,3 +242,18 @@ was deprecated in Elasticsearch 7.13.0, and is removed as of Elasticsearch
 Discontinue use of the removed setting. Specifying this setting in Elasticsearch
 configuration will result in an error on startup.
 ====
+
+[[shared-data-path-setting]]
+.Shared data path and per index data path settings deprecated
+[%collapsible]
+====
+*Details* +
+Elasticsearch uses the shared data path as the base path of per index data
+paths. This feature was previously used with shared replicas. Starting in
+7.13.0, these settings are deprecated. Starting in 8.0 only existing
+indices created in 7.x will be capable of using the shared data path and
+per index data path settings.
+
+*Impact* +
+Discontinue use of the deprecated settings.
+====

server/src/main/java/org/elasticsearch/cluster/metadata/IndexMetadata.java

@@ -282,7 +282,7 @@ public static APIBlock readFrom(StreamInput input) throws IOException {
     public static final String SETTING_HISTORY_UUID = "index.history.uuid";
     public static final String SETTING_DATA_PATH = "index.data_path";
     public static final Setting<String> INDEX_DATA_PATH_SETTING =
-        new Setting<>(SETTING_DATA_PATH, "", Function.identity(), Property.IndexScope);
+        new Setting<>(SETTING_DATA_PATH, "", Function.identity(), Property.IndexScope, Property.Deprecated);
     public static final String INDEX_UUID_NA_VALUE = "_na_";
 
     public static final String INDEX_ROUTING_REQUIRE_GROUP_PREFIX = "index.routing.allocation.require";

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

@@ -46,7 +46,8 @@ public class Environment {
             new Setting<>("path.logs", "", Function.identity(), Property.NodeScope);
     public static final Setting<List<String>> PATH_REPO_SETTING =
         Setting.listSetting("path.repo", Collections.emptyList(), Function.identity(), Property.NodeScope);
-    public static final Setting<String> PATH_SHARED_DATA_SETTING = Setting.simpleString("path.shared_data", Property.NodeScope);
+    public static final Setting<String> PATH_SHARED_DATA_SETTING = Setting.simpleString("path.shared_data",
+        Property.NodeScope, Property.Deprecated);
     public static final Setting<String> NODE_PIDFILE_SETTING = Setting.simpleString("node.pidfile", Property.NodeScope);
 
     private final Settings settings;

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

@@ -8,6 +8,7 @@
 package org.elasticsearch.env;
 
 import org.elasticsearch.common.io.PathUtils;
+import org.elasticsearch.common.settings.Setting;
 import org.elasticsearch.common.settings.Settings;
 import org.elasticsearch.test.ESTestCase;
 
@@ -17,6 +18,7 @@
 import java.nio.file.Path;
 import java.util.List;
 
+import static org.elasticsearch.common.inject.matcher.Matchers.not;
 import static org.hamcrest.CoreMatchers.endsWith;
 import static org.hamcrest.CoreMatchers.notNullValue;
 import static org.hamcrest.CoreMatchers.nullValue;
@@ -191,6 +193,15 @@ public void testSingleDataPathListCheck() {
         }
     }
 
+    public void testSharedDataPathDeprecation() {
+        final Settings settings = Settings.builder()
+            .put(Environment.PATH_HOME_SETTING.getKey(), createTempDir())
+            .put(Environment.PATH_SHARED_DATA_SETTING.getKey(), createTempDir()).build();
+        Environment env = new Environment(settings, null);
+        assertThat(env.sharedDataFile(), notNullValue());
+        assertSettingDeprecationsAndWarnings(new Setting[] { Environment.PATH_SHARED_DATA_SETTING });
+    }
+
     private void assertPath(final String actual, final Path expected) {
         assertIsAbsolute(actual);
         assertIsNormalized(actual);
@@ -204,5 +215,4 @@ private void assertIsAbsolute(final String path) {
     private void assertIsNormalized(final String path) {
         assertThat("path [" + path + "] is not normalized", PathUtils.get(path), equalTo(PathUtils.get(path).normalize()));
     }
-
 }

server/src/test/java/org/elasticsearch/index/IndexSettingsTests.java

@@ -30,6 +30,7 @@
 import java.util.function.Function;
 
 import static org.hamcrest.CoreMatchers.equalTo;
+import static org.hamcrest.Matchers.is;
 import static org.hamcrest.core.StringContains.containsString;
 import static org.hamcrest.object.HasToString.hasToString;
 
@@ -534,4 +535,14 @@ public void testSoftDeletesDefaultSetting() {
         Settings settings = Settings.builder().put(IndexMetadata.SETTING_VERSION_CREATED, createdVersion).build();
         assertTrue(IndexSettings.INDEX_SOFT_DELETES_SETTING.get(settings));
     }
+
+    public void testCustomDataPathDeprecated() {
+        final Settings settings = Settings.builder()
+            .put(IndexMetadata.INDEX_DATA_PATH_SETTING.getKey(), "my-custom-dir")
+            .build();
+        IndexMetadata metadata = newIndexMeta("test", settings);
+        IndexSettings indexSettings = new IndexSettings(metadata, Settings.EMPTY);
+        assertThat(indexSettings.hasCustomDataPath(), is(true));
+        assertSettingDeprecationsAndWarnings(new Setting[] { IndexMetadata.INDEX_DATA_PATH_SETTING });
+    }
 }

x-pack/plugin/deprecation/src/main/java/org/elasticsearch/xpack/deprecation/DeprecationChecks.java

@@ -32,10 +32,15 @@ private DeprecationChecks() {
     static List<Function<ClusterState, DeprecationIssue>> CLUSTER_SETTINGS_CHECKS =
         Collections.emptyList();
 
-    static List<BiFunction<Settings, PluginsAndModules, DeprecationIssue>> NODE_SETTINGS_CHECKS = List.of();
+    static List<BiFunction<Settings, PluginsAndModules, DeprecationIssue>> NODE_SETTINGS_CHECKS = List.of(
+        NodeDeprecationChecks::checkSharedDataPathSetting
+    );
 
-    static List<Function<IndexMetadata, DeprecationIssue>> INDEX_SETTINGS_CHECKS =
-            List.of(IndexDeprecationChecks::oldIndicesCheck, IndexDeprecationChecks::translogRetentionSettingCheck);
+    static List<Function<IndexMetadata, DeprecationIssue>> INDEX_SETTINGS_CHECKS = List.of(
+        IndexDeprecationChecks::oldIndicesCheck,
+        IndexDeprecationChecks::translogRetentionSettingCheck,
+        IndexDeprecationChecks::checkIndexDataPath
+        );
 
     /**
      * helper utility function to reduce repeat of running a specific {@link List} of checks.
@@ -48,4 +53,5 @@ private DeprecationChecks() {
     static <T> List<DeprecationIssue> filterChecks(List<T> checks, Function<T, DeprecationIssue> mapper) {
         return checks.stream().map(mapper).filter(Objects::nonNull).collect(Collectors.toList());
     }
+
 }

x-pack/plugin/deprecation/src/main/java/org/elasticsearch/xpack/deprecation/IndexDeprecationChecks.java

@@ -10,9 +10,11 @@
 import org.elasticsearch.Version;
 import org.elasticsearch.cluster.metadata.IndexMetadata;
 import org.elasticsearch.cluster.metadata.MappingMetadata;
+import org.elasticsearch.env.Environment;
 import org.elasticsearch.index.IndexSettings;
 import org.elasticsearch.xpack.core.deprecation.DeprecationIssue;
 
+import java.util.Locale;
 import java.util.Map;
 import java.util.function.BiConsumer;
 
@@ -55,4 +57,16 @@ static DeprecationIssue translogRetentionSettingCheck(IndexMetadata indexMetadat
         }
         return null;
     }
+
+    static DeprecationIssue checkIndexDataPath(IndexMetadata indexMetadata) {
+        if (IndexMetadata.INDEX_DATA_PATH_SETTING.exists(indexMetadata.getSettings())) {
+            final String message = String.format(Locale.ROOT,
+                "setting [%s] is deprecated and will be removed in a future version", IndexMetadata.INDEX_DATA_PATH_SETTING.getKey());
+            final String url =
+                "https://www.elastic.co/guide/en/elasticsearch/reference/7.13/breaking-changes-7.13.html#deprecate-shared-data-path-setting";
+            final String details = "Found index data path configured. Discontinue use of this setting.";
+            return new DeprecationIssue(DeprecationIssue.Level.CRITICAL, message, url, details);
+        }
+        return null;
+    }
 }

x-pack/plugin/deprecation/src/main/java/org/elasticsearch/xpack/deprecation/NodeDeprecationChecks.java

@@ -8,8 +8,10 @@
 package org.elasticsearch.xpack.deprecation;
 
 import org.elasticsearch.action.admin.cluster.node.info.PluginsAndModules;
+import org.elasticsearch.bootstrap.BootstrapSettings;
 import org.elasticsearch.common.settings.Setting;
 import org.elasticsearch.common.settings.Settings;
+import org.elasticsearch.env.Environment;
 import org.elasticsearch.xpack.core.deprecation.DeprecationIssue;
 
 import java.util.Locale;
@@ -113,4 +115,15 @@ static DeprecationIssue checkRemovedSetting(final Settings settings, final Setti
         return new DeprecationIssue(DeprecationIssue.Level.CRITICAL, message, url, details);
     }
 
+    static DeprecationIssue checkSharedDataPathSetting(final Settings settings, final PluginsAndModules pluginsAndModules) {
+        if (Environment.PATH_SHARED_DATA_SETTING.exists(settings)) {
+            final String message = String.format(Locale.ROOT,
+                "setting [%s] is deprecated and will be removed in a future version", Environment.PATH_SHARED_DATA_SETTING.getKey());
+            final String url =
+                "https://www.elastic.co/guide/en/elasticsearch/reference/7.13/breaking-changes-7.13.html#deprecate-shared-data-path-setting";
+            final String details = "Found shared data path configured. Discontinue use of this setting.";
+            return new DeprecationIssue(DeprecationIssue.Level.CRITICAL, message, url, details);
+        }
+        return null;
+    }
 }

x-pack/plugin/deprecation/src/test/java/org/elasticsearch/xpack/deprecation/IndexDeprecationChecksTests.java

@@ -64,4 +64,19 @@ public void testDefaultTranslogRetentionSettings() {
         List<DeprecationIssue> issues = DeprecationChecks.filterChecks(INDEX_SETTINGS_CHECKS, c -> c.apply(indexMetadata));
         assertThat(issues, empty());
     }
+
+    public void testIndexDataPathSetting() {
+        Settings.Builder settings = settings(Version.CURRENT);
+        settings.put(IndexMetadata.INDEX_DATA_PATH_SETTING.getKey(), createTempDir());
+        IndexMetadata indexMetadata = IndexMetadata.builder("test").settings(settings).numberOfShards(1).numberOfReplicas(0).build();
+        List<DeprecationIssue> issues = DeprecationChecks.filterChecks(INDEX_SETTINGS_CHECKS, c -> c.apply(indexMetadata));
+        final String expectedUrl =
+            "https://www.elastic.co/guide/en/elasticsearch/reference/7.13/breaking-changes-7.13.html#deprecate-shared-data-path-setting";
+        assertThat(issues, contains(
+            new DeprecationIssue(DeprecationIssue.Level.CRITICAL,
+                "setting [index.data_path] is deprecated and will be removed in a future version",
+                expectedUrl,
+                "Found index data path configured. Discontinue use of this setting."
+        )));
+    }
 }

x-pack/plugin/deprecation/src/test/java/org/elasticsearch/xpack/deprecation/NodeDeprecationChecksTests.java

@@ -7,14 +7,22 @@
 
 package org.elasticsearch.xpack.deprecation;
 
+import org.elasticsearch.Version;
+import org.elasticsearch.cluster.metadata.IndexMetadata;
 import org.elasticsearch.common.settings.Setting;
 import org.elasticsearch.common.settings.Settings;
+import org.elasticsearch.env.Environment;
 import org.elasticsearch.test.ESTestCase;
 import org.elasticsearch.xpack.core.deprecation.DeprecationIssue;
 
+import java.util.List;
+
+import static org.elasticsearch.xpack.deprecation.DeprecationChecks.INDEX_SETTINGS_CHECKS;
+import static org.elasticsearch.xpack.deprecation.DeprecationChecks.NODE_SETTINGS_CHECKS;
 import static org.hamcrest.Matchers.equalTo;
 import static org.hamcrest.Matchers.not;
 import static org.hamcrest.Matchers.nullValue;
+import static org.hamcrest.collection.IsIterableContainingInOrder.contains;
 
 public class NodeDeprecationChecksTests extends ESTestCase {
 
@@ -42,4 +50,19 @@ public void testRemovedSetting() {
         assertThat(issue.getUrl(), equalTo("https://removed-setting.example.com"));
     }
 
+    public void testSharedDataPathSetting() {
+        Settings settings = Settings.builder()
+            .put(Environment.PATH_HOME_SETTING.getKey(), createTempDir())
+            .put(Environment.PATH_SHARED_DATA_SETTING.getKey(), createTempDir()).build();
+
+        List<DeprecationIssue> issues = DeprecationChecks.filterChecks(NODE_SETTINGS_CHECKS, c -> c.apply(settings, null));
+        final String expectedUrl =
+            "https://www.elastic.co/guide/en/elasticsearch/reference/7.13/breaking-changes-7.13.html#deprecate-shared-data-path-setting";
+        assertThat(issues, contains(
+            new DeprecationIssue(DeprecationIssue.Level.CRITICAL,
+                "setting [path.shared_data] is deprecated and will be removed in a future version",
+                expectedUrl,
+                "Found shared data path configured. Discontinue use of this setting."
+            )));
+    }
 }