Add version guards around Transform hidden index settings (#54036)

This commit ensures that the hidden index settings are only applied to the
Transform index templates when the cluster can support those settings.

Also unmutes the tests which were failing due to the previous behavior.

Author: gwbrown

x-pack/plugin/transform/src/main/java/org/elasticsearch/xpack/transform/Transform.java

@@ -9,6 +9,7 @@
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.apache.lucene.util.SetOnce;
+import org.elasticsearch.Version;
 import org.elasticsearch.action.ActionRequest;
 import org.elasticsearch.action.ActionResponse;
 import org.elasticsearch.client.Client;
@@ -320,7 +321,10 @@ public UnaryOperator<Map<String, IndexTemplateMetaData>> getIndexTemplateMetaDat
                 logger.error("Error creating transform index template", e);
             }
             try {
-                templates.put(TransformInternalIndexConstants.AUDIT_INDEX, TransformInternalIndex.getAuditIndexTemplateMetaData());
+                // Template upgraders are only ever called on the master nodes, so we can use the current node version as the compatibility
+                // version here because we can be sure that this node, if elected master, will be compatible with itself.
+                templates.put(TransformInternalIndexConstants.AUDIT_INDEX,
+                    TransformInternalIndex.getAuditIndexTemplateMetaData(Version.CURRENT));
             } catch (IOException e) {
                 logger.warn("Error creating transform audit index", e);
             }

x-pack/plugin/transform/src/main/java/org/elasticsearch/xpack/transform/TransformClusterStateListener.java

@@ -23,6 +23,7 @@
 
 import static org.elasticsearch.xpack.core.ClientHelper.TRANSFORM_ORIGIN;
 import static org.elasticsearch.xpack.core.ClientHelper.executeAsyncWithOrigin;
+import static org.elasticsearch.xpack.transform.persistence.TransformInternalIndex.HIDDEN_INTRODUCED_VERSION;
 
 class TransformClusterStateListener implements ClusterStateListener {
 
@@ -77,11 +78,16 @@ private static void createAuditAliasForDataFrameBWC(ClusterState state, Client c
             return;
         }
 
+        final IndicesAliasesRequest.AliasActions aliasAction = IndicesAliasesRequest.AliasActions.add()
+            .index(TransformInternalIndexConstants.AUDIT_INDEX_DEPRECATED)
+            .alias(TransformInternalIndexConstants.AUDIT_INDEX_READ_ALIAS);
+
+        if (state.nodes().getMinNodeVersion().onOrAfter(HIDDEN_INTRODUCED_VERSION)) {
+            aliasAction.isHidden(true);
+        }
+
         final IndicesAliasesRequest request = client.admin().indices().prepareAliases()
-                .addAliasAction(IndicesAliasesRequest.AliasActions.add()
-                    .index(TransformInternalIndexConstants.AUDIT_INDEX_DEPRECATED)
-                    .alias(TransformInternalIndexConstants.AUDIT_INDEX_READ_ALIAS)
-                    .isHidden(true))
+                .addAliasAction(aliasAction)
                 .request();
 
         executeAsyncWithOrigin(client.threadPool().getThreadContext(), TRANSFORM_ORIGIN, request,

x-pack/plugin/transform/src/main/java/org/elasticsearch/xpack/transform/persistence/TransformInternalIndex.java

@@ -39,6 +39,7 @@
 import java.io.IOException;
 import java.util.Collections;
 
+import static org.elasticsearch.cluster.metadata.IndexMetaData.SETTING_INDEX_HIDDEN;
 import static org.elasticsearch.common.xcontent.XContentFactory.jsonBuilder;
 import static org.elasticsearch.index.mapper.MapperService.SINGLE_MAPPING_NAME;
 import static org.elasticsearch.xpack.core.ClientHelper.TRANSFORM_ORIGIN;
@@ -79,6 +80,8 @@ public final class TransformInternalIndex {
     public static final String KEYWORD = "keyword";
     public static final String BOOLEAN = "boolean";
 
+    public static final Version HIDDEN_INTRODUCED_VERSION = Version.V_7_7_0;
+
     public static IndexTemplateMetaData getIndexTemplateMetaData() throws IOException {
         IndexTemplateMetaData transformTemplate = IndexTemplateMetaData.builder(TransformInternalIndexConstants.LATEST_INDEX_VERSIONED_NAME)
             .patterns(Collections.singletonList(TransformInternalIndexConstants.LATEST_INDEX_VERSIONED_NAME))
@@ -97,19 +100,22 @@ public static IndexTemplateMetaData getIndexTemplateMetaData() throws IOExceptio
         return transformTemplate;
     }
 
-    public static IndexTemplateMetaData getAuditIndexTemplateMetaData() throws IOException {
+    public static IndexTemplateMetaData getAuditIndexTemplateMetaData(Version compatibilityVersion) throws IOException {
+        final Settings.Builder auditIndexSettings = Settings.builder()
+            // the audits are expected to be small
+            .put(IndexMetaData.SETTING_NUMBER_OF_SHARDS, 1)
+            .put(IndexMetaData.SETTING_AUTO_EXPAND_REPLICAS, "0-1");
+        final AliasMetaData.Builder alias = AliasMetaData.builder(TransformInternalIndexConstants.AUDIT_INDEX_READ_ALIAS);
+        if (compatibilityVersion.onOrAfter(HIDDEN_INTRODUCED_VERSION)) {
+            auditIndexSettings.put(SETTING_INDEX_HIDDEN, true);
+            alias.isHidden(true);
+        }
         IndexTemplateMetaData transformTemplate = IndexTemplateMetaData.builder(TransformInternalIndexConstants.AUDIT_INDEX)
             .patterns(Collections.singletonList(TransformInternalIndexConstants.AUDIT_INDEX_PREFIX + "*"))
             .version(Version.CURRENT.id)
-            .settings(
-                Settings.builder()
-                    // the audits are expected to be small
-                    .put(IndexMetaData.SETTING_NUMBER_OF_SHARDS, 1)
-                    .put(IndexMetaData.SETTING_AUTO_EXPAND_REPLICAS, "0-1")
-                    .put(IndexMetaData.SETTING_INDEX_HIDDEN, true)
-            )
+            .settings(auditIndexSettings)
             .putMapping(MapperService.SINGLE_MAPPING_NAME, Strings.toString(auditMappings()))
-            .putAlias(AliasMetaData.builder(TransformInternalIndexConstants.AUDIT_INDEX_READ_ALIAS).isHidden(true))
+            .putAlias(alias)
             .build();
         return transformTemplate;
     }
@@ -406,7 +412,7 @@ protected static void installLatestAuditIndexTemplateIfRequired(
 
         // Installing the template involves communication with the master node, so it's more expensive but much rarer
         try {
-            IndexTemplateMetaData indexTemplateMetaData = getAuditIndexTemplateMetaData();
+            IndexTemplateMetaData indexTemplateMetaData = getAuditIndexTemplateMetaData(clusterService.state().nodes().getMinNodeVersion());
             BytesReference jsonMappings = new BytesArray(indexTemplateMetaData.mappings().get(SINGLE_MAPPING_NAME).uncompressed());
             PutIndexTemplateRequest request = new PutIndexTemplateRequest(TransformInternalIndexConstants.AUDIT_INDEX).patterns(
                 indexTemplateMetaData.patterns()

x-pack/plugin/transform/src/test/java/org/elasticsearch/xpack/transform/persistence/TransformInternalIndexTests.java

@@ -6,6 +6,7 @@
 
 package org.elasticsearch.xpack.transform.persistence;
 
+import org.elasticsearch.Version;
 import org.elasticsearch.action.ActionListener;
 import org.elasticsearch.action.support.master.AcknowledgedResponse;
 import org.elasticsearch.client.AdminClient;
@@ -55,7 +56,8 @@ public class TransformInternalIndexTests extends ESTestCase {
 
         mapBuilder = ImmutableOpenMap.builder();
         try {
-            mapBuilder.put(TransformInternalIndexConstants.AUDIT_INDEX, TransformInternalIndex.getAuditIndexTemplateMetaData());
+            mapBuilder.put(TransformInternalIndexConstants.AUDIT_INDEX,
+                TransformInternalIndex.getAuditIndexTemplateMetaData(Version.CURRENT));
         } catch (IOException e) {
             throw new UncheckedIOException(e);
         }

x-pack/qa/rolling-upgrade/src/test/java/org/elasticsearch/upgrades/TransformSurvivesUpgradeIT.java

@@ -128,7 +128,6 @@ protected RestClient buildClient(Settings settings, HttpHost[] hosts) throws IOE
      * The purpose of this test is to ensure that when a job is open through a rolling upgrade we upgrade the results
      * index mappings when it is assigned to an upgraded node even if no other ML endpoint is called after the upgrade
      */
-    @AwaitsFix(bugUrl = "https://github.com/elastic/elasticsearch/issues/53931")
     public void testTransformRollingUpgrade() throws Exception {
         assumeTrue("Continuous transform time sync not fixed until 7.4", UPGRADE_FROM_VERSION.onOrAfter(Version.V_7_4_0));
         Request adjustLoggingLevels = new Request("PUT", "/_cluster/settings");

x-pack/qa/rolling-upgrade/src/test/resources/rest-api-spec/test/mixed_cluster/80_transform_jobs_crud.yml

@@ -1,8 +1,3 @@
-setup:
-  - skip:
-      version: "all"
-      reason:  "AwaitsFix https://github.com/elastic/elasticsearch/issues/53931"
-
 ---
 "Test put batch transform on mixed cluster":
   - skip:

x-pack/qa/rolling-upgrade/src/test/resources/rest-api-spec/test/upgraded_cluster/80_transform_jobs_crud.yml

@@ -1,8 +1,4 @@
 setup:
-  - skip:
-      version: "all"
-      reason:  "AwaitsFix https://github.com/elastic/elasticsearch/issues/53931"
-
   - do:
       cluster.health:
         wait_for_status: green