[Transform] Encapsulate plugin-level settings into a `TransformExtens…

…ion` interface (#98978)

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

@@ -0,0 +1,36 @@
+/*
+ * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+ * or more contributor license agreements. Licensed under the Elastic License
+ * 2.0; you may not use this file except in compliance with the Elastic License
+ * 2.0.
+ */
+
+package org.elasticsearch.xpack.transform;
+
+import org.elasticsearch.cluster.metadata.IndexMetadata;
+import org.elasticsearch.common.settings.Settings;
+
+public class DefaultTransformExtension implements TransformExtension {
+
+    @Override
+    public boolean includeNodeInfo() {
+        return true;
+    }
+
+    @Override
+    public Settings getTransformInternalIndexAdditionalSettings() {
+        return Settings.EMPTY;
+    }
+
+    /**
+     * Provides destination index settings, hardcoded at the moment. In future this might be customizable or generation could be based on
+     * source settings.
+     */
+    @Override
+    public Settings getTransformDestinationIndexSettings() {
+        return Settings.builder()
+            .put(IndexMetadata.SETTING_NUMBER_OF_SHARDS, 1)
+            .put(IndexMetadata.SETTING_AUTO_EXPAND_REPLICAS, "0-1")
+            .build();
+    }
+}

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

@@ -137,6 +137,7 @@ public class Transform extends Plugin implements SystemIndexPlugin, PersistentTa
 
     private final Settings settings;
     private final SetOnce<TransformServices> transformServices = new SetOnce<>();
+    private final TransformExtension transformExtension = new DefaultTransformExtension();
 
     public static final Integer DEFAULT_INITIAL_MAX_PAGE_SEARCH_SIZE = Integer.valueOf(500);
     public static final TimeValue DEFAULT_TRANSFORM_FREQUENCY = TimeValue.timeValueSeconds(60);
@@ -250,7 +251,12 @@ public Collection<Object> createComponents(
             client,
             xContentRegistry
         );
-        TransformAuditor auditor = new TransformAuditor(client, clusterService.getNodeName(), clusterService, includeNodeInfo());
+        TransformAuditor auditor = new TransformAuditor(
+            client,
+            clusterService.getNodeName(),
+            clusterService,
+            getTransformExtension().includeNodeInfo()
+        );
         Clock clock = Clock.systemUTC();
         TransformCheckpointService checkpointService = new TransformCheckpointService(
             clock,
@@ -264,7 +270,11 @@ public Collection<Object> createComponents(
 
         transformServices.set(new TransformServices(configManager, checkpointService, auditor, scheduler));
 
-        return Arrays.asList(transformServices.get(), new TransformClusterStateListener(clusterService, client));
+        return Arrays.asList(
+            transformServices.get(),
+            new TransformClusterStateListener(clusterService, client),
+            new TransformExtensionHolder(getTransformExtension())
+        );
     }
 
     @Override
@@ -285,7 +295,7 @@ public List<PersistentTasksExecutor<?>> getPersistentTasksExecutor(
                 threadPool,
                 clusterService,
                 settingsModule.getSettings(),
-                getTransformInternalIndexAdditionalSettings(),
+                getTransformExtension().getTransformInternalIndexAdditionalSettings(),
                 expressionResolver
             )
         );
@@ -354,7 +364,9 @@ public UnaryOperator<Map<String, IndexTemplateMetadata>> getIndexTemplateMetadat
     @Override
     public Collection<SystemIndexDescriptor> getSystemIndexDescriptors(Settings settings) {
         try {
-            return List.of(TransformInternalIndex.getSystemIndexDescriptor(getTransformInternalIndexAdditionalSettings()));
+            return List.of(
+                TransformInternalIndex.getSystemIndexDescriptor(getTransformExtension().getTransformInternalIndexAdditionalSettings())
+            );
         } catch (IOException e) {
             throw new UncheckedIOException(e);
         }
@@ -467,11 +479,17 @@ public String getFeatureDescription() {
         return "Manages configuration and state for transforms";
     }
 
+    public TransformExtension getTransformExtension() {
+        return transformExtension;
+    }
+
+    @Deprecated
     public boolean includeNodeInfo() {
-        return true;
+        return getTransformExtension().includeNodeInfo();
     }
 
+    @Deprecated
     public Settings getTransformInternalIndexAdditionalSettings() {
-        return Settings.EMPTY;
+        return getTransformExtension().getTransformInternalIndexAdditionalSettings();
     }
 }

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

@@ -0,0 +1,23 @@
+/*
+ * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+ * or more contributor license agreements. Licensed under the Elastic License
+ * 2.0; you may not use this file except in compliance with the Elastic License
+ * 2.0.
+ */
+
+package org.elasticsearch.xpack.transform;
+
+import org.elasticsearch.common.settings.Settings;
+
+public interface TransformExtension {
+
+    boolean includeNodeInfo();
+
+    Settings getTransformInternalIndexAdditionalSettings();
+
+    /**
+     * Provides destination index settings, hardcoded at the moment. In future this might be customizable or generation could be based on
+     * source settings.
+     */
+    Settings getTransformDestinationIndexSettings();
+}

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

@@ -0,0 +1,41 @@
+/*
+ * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+ * or more contributor license agreements. Licensed under the Elastic License
+ * 2.0; you may not use this file except in compliance with the Elastic License
+ * 2.0.
+ */
+
+package org.elasticsearch.xpack.transform;
+
+import org.elasticsearch.node.Node;
+
+import java.util.Objects;
+
+/**
+ * Wrapper for the {@link TransformExtension} interface that allows it to be used
+ * given the way {@link Node} does Guice bindings for plugin components.
+ * TODO: remove this class entirely once Guice is removed entirely.
+ */
+public class TransformExtensionHolder {
+
+    private final TransformExtension transformExtension;
+
+    /**
+     * Used by Guice.
+     */
+    public TransformExtensionHolder() {
+        this.transformExtension = null;
+    }
+
+    public TransformExtensionHolder(TransformExtension transformExtension) {
+        this.transformExtension = Objects.requireNonNull(transformExtension);
+    }
+
+    public boolean isEmpty() {
+        return transformExtension == null;
+    }
+
+    public TransformExtension getTransformExtension() {
+        return transformExtension;
+    }
+}

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

@@ -125,6 +125,7 @@ public static void updateTransform(
         final boolean dryRun,
         final boolean checkAccess,
         final TimeValue timeout,
+        final Settings destIndexSettings,
         ActionListener<UpdateResult> listener
     ) {
         // rewrite config into a new format if necessary
@@ -185,6 +186,7 @@ public static void updateTransform(
                 destIndexMappings,
                 seqNoPrimaryTermAndIndex,
                 clusterState,
+                destIndexSettings,
                 ActionListener.wrap(r -> updateTransformListener.onResponse(null), listener::onFailure)
             );
         }, listener::onFailure);
@@ -300,6 +302,7 @@ private static void updateTransformConfiguration(
         Map<String, String> mappings,
         SeqNoPrimaryTermAndIndex seqNoPrimaryTermAndIndex,
         ClusterState clusterState,
+        Settings destIndexSettings,
         ActionListener<Void> listener
     ) {
         // <3> Return to the listener
@@ -351,6 +354,7 @@ private static void updateTransformConfiguration(
                 indexNameExpressionResolver,
                 clusterState,
                 config,
+                destIndexSettings,
                 mappings,
                 createDestinationListener
             );

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

@@ -50,6 +50,7 @@
 import org.elasticsearch.xpack.core.transform.transforms.SyncConfig;
 import org.elasticsearch.xpack.core.transform.transforms.TransformConfig;
 import org.elasticsearch.xpack.core.transform.transforms.TransformDestIndexSettings;
+import org.elasticsearch.xpack.transform.TransformExtensionHolder;
 import org.elasticsearch.xpack.transform.persistence.TransformIndex;
 import org.elasticsearch.xpack.transform.transforms.Function;
 import org.elasticsearch.xpack.transform.transforms.FunctionFactory;
@@ -78,6 +79,7 @@ public class TransportPreviewTransformAction extends HandledTransportAction<Requ
     private final TransportService transportService;
     private final Settings nodeSettings;
     private final SourceDestValidator sourceDestValidator;
+    private final Settings destIndexSettings;
 
     @Inject
     public TransportPreviewTransformAction(
@@ -88,7 +90,8 @@ public TransportPreviewTransformAction(
         IndexNameExpressionResolver indexNameExpressionResolver,
         ClusterService clusterService,
         Settings settings,
-        IngestService ingestService
+        IngestService ingestService,
+        TransformExtensionHolder transformExtensionHolder
     ) {
         super(PreviewTransformAction.NAME, transportService, actionFilters, Request::new);
         this.securityContext = XPackSettings.SECURITY_ENABLED.get(settings)
@@ -111,6 +114,7 @@ public TransportPreviewTransformAction(
             clusterService.getNodeName(),
             License.OperationMode.BASIC.description()
         );
+        this.destIndexSettings = transformExtensionHolder.getTransformExtension().getTransformDestinationIndexSettings();
     }
 
     @Override
@@ -236,6 +240,7 @@ private void getPreview(
                 HeaderWarning.addWarning("Pipeline returned " + errors.size() + " errors, first error: " + errors.get(0));
             }
             TransformDestIndexSettings generatedDestIndexSettings = TransformIndex.createTransformDestIndexSettings(
+                destIndexSettings,
                 mappings.get(),
                 transformId,
                 Clock.systemUTC()
@@ -249,6 +254,7 @@ private void getPreview(
         ActionListener<List<Map<String, Object>>> previewListener = ActionListener.wrap(docs -> {
             if (pipeline == null) {
                 TransformDestIndexSettings generatedDestIndexSettings = TransformIndex.createTransformDestIndexSettings(
+                    destIndexSettings,
                     mappings.get(),
                     transformId,
                     Clock.systemUTC()

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

@@ -37,6 +37,7 @@
 import org.elasticsearch.xpack.core.transform.action.StopTransformAction;
 import org.elasticsearch.xpack.core.transform.transforms.TransformConfig;
 import org.elasticsearch.xpack.core.transform.transforms.TransformConfigUpdate;
+import org.elasticsearch.xpack.transform.TransformExtensionHolder;
 import org.elasticsearch.xpack.transform.TransformServices;
 import org.elasticsearch.xpack.transform.notifications.TransformAuditor;
 import org.elasticsearch.xpack.transform.persistence.SeqNoPrimaryTermAndIndex;
@@ -58,6 +59,7 @@ public class TransportResetTransformAction extends AcknowledgedTransportMasterNo
     private final Client client;
     private final SecurityContext securityContext;
     private final Settings settings;
+    private final Settings destIndexSettings;
 
     @Inject
     public TransportResetTransformAction(
@@ -68,7 +70,8 @@ public TransportResetTransformAction(
         IndexNameExpressionResolver indexNameExpressionResolver,
         TransformServices transformServices,
         Client client,
-        Settings settings
+        Settings settings,
+        TransformExtensionHolder transformExtensionHolder
     ) {
         super(
             ResetTransformAction.NAME,
@@ -87,6 +90,7 @@ public TransportResetTransformAction(
             ? new SecurityContext(settings, threadPool.getThreadContext())
             : null;
         this.settings = settings;
+        this.destIndexSettings = transformExtensionHolder.getTransformExtension().getTransformDestinationIndexSettings();
     }
 
     @Override
@@ -131,6 +135,7 @@ protected void masterOperation(Task task, Request request, ClusterState state, A
                     false, // dry run
                     false, // check access
                     request.timeout(),
+                    destIndexSettings,
                     updateTransformListener
                 );
             },

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

@@ -23,6 +23,7 @@
 import org.elasticsearch.cluster.metadata.IndexNameExpressionResolver;
 import org.elasticsearch.cluster.service.ClusterService;
 import org.elasticsearch.common.inject.Inject;
+import org.elasticsearch.common.settings.Settings;
 import org.elasticsearch.core.TimeValue;
 import org.elasticsearch.health.HealthStatus;
 import org.elasticsearch.persistent.PersistentTasksCustomMetadata;
@@ -40,6 +41,7 @@
 import org.elasticsearch.xpack.core.transform.transforms.TransformState;
 import org.elasticsearch.xpack.core.transform.transforms.TransformTaskParams;
 import org.elasticsearch.xpack.core.transform.transforms.TransformTaskState;
+import org.elasticsearch.xpack.transform.TransformExtensionHolder;
 import org.elasticsearch.xpack.transform.TransformServices;
 import org.elasticsearch.xpack.transform.notifications.TransformAuditor;
 import org.elasticsearch.xpack.transform.persistence.AuthorizationStatePersistenceUtils;
@@ -62,6 +64,7 @@ public class TransportStartTransformAction extends TransportMasterNodeAction<Sta
     private final PersistentTasksService persistentTasksService;
     private final Client client;
     private final TransformAuditor auditor;
+    private final Settings destIndexSettings;
 
     @Inject
     public TransportStartTransformAction(
@@ -72,7 +75,8 @@ public TransportStartTransformAction(
         IndexNameExpressionResolver indexNameExpressionResolver,
         TransformServices transformServices,
         PersistentTasksService persistentTasksService,
-        Client client
+        Client client,
+        TransformExtensionHolder transformExtensionHolder
     ) {
         this(
             StartTransformAction.NAME,
@@ -83,7 +87,8 @@ public TransportStartTransformAction(
             indexNameExpressionResolver,
             transformServices,
             persistentTasksService,
-            client
+            client,
+            transformExtensionHolder
         );
     }
 
@@ -96,7 +101,8 @@ protected TransportStartTransformAction(
         IndexNameExpressionResolver indexNameExpressionResolver,
         TransformServices transformServices,
         PersistentTasksService persistentTasksService,
-        Client client
+        Client client,
+        TransformExtensionHolder transformExtensionHolder
     ) {
         super(
             name,
@@ -113,6 +119,7 @@ protected TransportStartTransformAction(
         this.persistentTasksService = persistentTasksService;
         this.client = client;
         this.auditor = transformServices.getAuditor();
+        this.destIndexSettings = transformExtensionHolder.getTransformExtension().getTransformDestinationIndexSettings();
     }
 
     @Override
@@ -191,6 +198,7 @@ protected void masterOperation(
                 indexNameExpressionResolver,
                 state,
                 transformConfigHolder.get(),
+                destIndexSettings,
                 validationResponse.getDestIndexMappings(),
                 createOrGetIndexListener
             );