Make persistent tasks work.

Made persistent tasks executors pluggable.

server/src/main/java/org/elasticsearch/action/ActionModule.java

@@ -312,9 +312,12 @@
 import org.elasticsearch.rest.action.search.RestMultiSearchAction;
 import org.elasticsearch.rest.action.search.RestSearchAction;
 import org.elasticsearch.rest.action.search.RestSearchScrollAction;
-import org.elasticsearch.tasks.TaskManager;
 import org.elasticsearch.threadpool.ThreadPool;
 import org.elasticsearch.usage.UsageService;
+import org.elasticsearch.persistent.CompletionPersistentTaskAction;
+import org.elasticsearch.persistent.RemovePersistentTaskAction;
+import org.elasticsearch.persistent.StartPersistentTaskAction;
+import org.elasticsearch.persistent.UpdatePersistentTaskStatusAction;
 
 import java.util.ArrayList;
 import java.util.Collections;
@@ -507,6 +510,12 @@ public <Request extends ActionRequest, Response extends ActionResponse> void reg
 
         actionPlugins.stream().flatMap(p -> p.getActions().stream()).forEach(actions::register);
 
+        // Persistent tasks:
+        actions.register(StartPersistentTaskAction.INSTANCE, StartPersistentTaskAction.TransportAction.class);
+        actions.register(UpdatePersistentTaskStatusAction.INSTANCE, UpdatePersistentTaskStatusAction.TransportAction.class);
+        actions.register(CompletionPersistentTaskAction.INSTANCE, CompletionPersistentTaskAction.TransportAction.class);
+        actions.register(RemovePersistentTaskAction.INSTANCE, RemovePersistentTaskAction.TransportAction.class);
+
         return unmodifiableMap(actions.getRegistry());
     }
 

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

@@ -117,6 +117,7 @@
 import org.elasticsearch.plugins.MapperPlugin;
 import org.elasticsearch.plugins.MetaDataUpgrader;
 import org.elasticsearch.plugins.NetworkPlugin;
+import org.elasticsearch.plugins.PersistentTaskPlugin;
 import org.elasticsearch.plugins.Plugin;
 import org.elasticsearch.plugins.PluginsService;
 import org.elasticsearch.plugins.RepositoryPlugin;
@@ -139,6 +140,10 @@
 import org.elasticsearch.transport.TransportService;
 import org.elasticsearch.usage.UsageService;
 import org.elasticsearch.watcher.ResourceWatcherService;
+import org.elasticsearch.persistent.PersistentTasksClusterService;
+import org.elasticsearch.persistent.PersistentTasksExecutor;
+import org.elasticsearch.persistent.PersistentTasksExecutorRegistry;
+import org.elasticsearch.persistent.PersistentTasksService;
 
 import java.io.BufferedWriter;
 import java.io.Closeable;
@@ -461,6 +466,17 @@ protected Node(final Environment environment, Collection<Class<? extends Plugin>
                 threadPool, scriptModule.getScriptService(), bigArrays, searchModule.getFetchPhase(),
                 responseCollectorService);
 
+            final List<PersistentTasksExecutor<?>> tasksExecutors = pluginsService
+                .filterPlugins(PersistentTaskPlugin.class).stream()
+                .map(p -> p.getPersistentTasksExecutor(clusterService))
+                .flatMap(List::stream)
+                .collect(toList());
+
+            final PersistentTasksExecutorRegistry registry = new PersistentTasksExecutorRegistry(settings, tasksExecutors);
+            final PersistentTasksClusterService persistentTasksClusterService =
+                new PersistentTasksClusterService(settings, registry, clusterService);
+            final PersistentTasksService persistentTasksService = new PersistentTasksService(settings, clusterService, threadPool, client);
+
             modules.add(b -> {
                     b.bind(Node.class).toInstance(this);
                     b.bind(NodeService.class).toInstance(nodeService);
@@ -504,6 +520,9 @@ protected Node(final Environment environment, Collection<Class<? extends Plugin>
                     }
                     httpBind.accept(b);
                     pluginComponents.stream().forEach(p -> b.bind((Class) p.getClass()).toInstance(p));
+                    b.bind(PersistentTasksService.class).toInstance(persistentTasksService);
+                    b.bind(PersistentTasksClusterService.class).toInstance(persistentTasksClusterService);
+                    b.bind(PersistentTasksExecutorRegistry.class).toInstance(registry);
                 }
             );
             injector = modules.createInjector();

server/src/main/java/org/elasticsearch/plugins/PersistentTaskPlugin.java

@@ -0,0 +1,39 @@
+/*
+ * Licensed to Elasticsearch under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+package org.elasticsearch.plugins;
+
+import org.elasticsearch.cluster.service.ClusterService;
+import org.elasticsearch.persistent.PersistentTasksExecutor;
+
+import java.util.Collections;
+import java.util.List;
+
+/**
+ * Plugin for registering persistent tasks executors.
+ */
+public interface PersistentTaskPlugin {
+
+    /**
+     * Returns additional persistent tasks executors added by this plugin.
+     */
+    default List<PersistentTasksExecutor<?>> getPersistentTasksExecutor(ClusterService clusterService) {
+        return Collections.emptyList();
+    }
+
+}

server/src/test/java/org/elasticsearch/persistent/TestPersistentTasksPlugin.java

@@ -54,6 +54,7 @@
 import org.elasticsearch.env.Environment;
 import org.elasticsearch.env.NodeEnvironment;
 import org.elasticsearch.plugins.ActionPlugin;
+import org.elasticsearch.plugins.PersistentTaskPlugin;
 import org.elasticsearch.plugins.Plugin;
 import org.elasticsearch.script.ScriptService;
 import org.elasticsearch.tasks.Task;
@@ -87,33 +88,16 @@
 /**
  * A plugin that adds a test persistent task.
  */
-public class TestPersistentTasksPlugin extends Plugin implements ActionPlugin {
+public class TestPersistentTasksPlugin extends Plugin implements ActionPlugin, PersistentTaskPlugin {
 
     @Override
     public List<ActionHandler<? extends ActionRequest, ? extends ActionResponse>> getActions() {
-        return Arrays.asList(
-                new ActionHandler<>(TestTaskAction.INSTANCE, TransportTestTaskAction.class),
-                new ActionHandler<>(StartPersistentTaskAction.INSTANCE, StartPersistentTaskAction.TransportAction.class),
-                new ActionHandler<>(UpdatePersistentTaskStatusAction.INSTANCE, UpdatePersistentTaskStatusAction.TransportAction.class),
-                new ActionHandler<>(CompletionPersistentTaskAction.INSTANCE, CompletionPersistentTaskAction.TransportAction.class),
-                new ActionHandler<>(RemovePersistentTaskAction.INSTANCE, RemovePersistentTaskAction.TransportAction.class)
-        );
+        return Collections.singletonList(new ActionHandler<>(TestTaskAction.INSTANCE, TransportTestTaskAction.class));
     }
 
     @Override
-    public Collection<Object> createComponents(Client client, ClusterService clusterService, ThreadPool threadPool,
-                                               ResourceWatcherService resourceWatcherService, ScriptService scriptService,
-                                               NamedXContentRegistry xContentRegistry, Environment environment,
-                                               NodeEnvironment nodeEnvironment, NamedWriteableRegistry namedWriteableRegistry) {
-        PersistentTasksService persistentTasksService = new PersistentTasksService(Settings.EMPTY, clusterService, threadPool, client);
-        TestPersistentTasksExecutor testPersistentAction = new TestPersistentTasksExecutor(Settings.EMPTY, clusterService);
-        PersistentTasksExecutorRegistry persistentTasksExecutorRegistry = new PersistentTasksExecutorRegistry(Settings.EMPTY,
-                Collections.singletonList(testPersistentAction));
-        return Arrays.asList(
-                persistentTasksService,
-                persistentTasksExecutorRegistry,
-                new PersistentTasksClusterService(Settings.EMPTY, persistentTasksExecutorRegistry, clusterService)
-        );
+    public List<PersistentTasksExecutor<?>> getPersistentTasksExecutor(ClusterService clusterService) {
+        return Collections.singletonList(new TestPersistentTasksExecutor(Settings.EMPTY, clusterService));
     }
 
     @Override