Add TaskManager to pluginServices (elastic#112687)

Provide access to the TaskManager in plugins so that a RemovedTaskListener can be registered. This will allow a plugin to monitor when submitted tasks complete.

Author: parkertimmins

docs/changelog/112687.yaml

@@ -0,0 +1,5 @@
+pr: 112687
+summary: Add `TaskManager` to `pluginServices`
+area: Infra/Metrics
+type: enhancement
+issues: []

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

@@ -855,7 +855,8 @@ private void construct(
             featureService,
             systemIndices,
             dataStreamGlobalRetentionSettings,
-            documentParsingProvider
+            documentParsingProvider,
+            taskManager
         );
 
         Collection<?> pluginComponents = pluginsService.flatMap(plugin -> {

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

@@ -24,6 +24,7 @@
 import org.elasticsearch.plugins.internal.DocumentParsingProvider;
 import org.elasticsearch.repositories.RepositoriesService;
 import org.elasticsearch.script.ScriptService;
+import org.elasticsearch.tasks.TaskManager;
 import org.elasticsearch.telemetry.TelemetryProvider;
 import org.elasticsearch.threadpool.ThreadPool;
 import org.elasticsearch.watcher.ResourceWatcherService;
@@ -48,5 +49,6 @@ public record PluginServiceInstances(
     FeatureService featureService,
     SystemIndices systemIndices,
     DataStreamGlobalRetentionSettings dataStreamGlobalRetentionSettings,
-    DocumentParsingProvider documentParsingProvider
+    DocumentParsingProvider documentParsingProvider,
+    TaskManager taskManager
 ) implements Plugin.PluginServices {}

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

@@ -31,6 +31,7 @@
 import org.elasticsearch.plugins.internal.DocumentParsingProvider;
 import org.elasticsearch.repositories.RepositoriesService;
 import org.elasticsearch.script.ScriptService;
+import org.elasticsearch.tasks.TaskManager;
 import org.elasticsearch.telemetry.TelemetryProvider;
 import org.elasticsearch.threadpool.ExecutorBuilder;
 import org.elasticsearch.threadpool.ThreadPool;
@@ -165,6 +166,12 @@ public interface PluginServices {
          * A provider of utilities to observe and report parsing of documents
          */
         DocumentParsingProvider documentParsingProvider();
+
+        /**
+         * The task manager for the node. This should only be used by plugins
+         * to track task removal by registering a RemovedTaskListener.
+         */
+        TaskManager taskManager();
     }
 
     /**