Use executor's describeTasks method to log task information in cluster service (#19531)

This fixes the log output in some places of ClusterService where the executor's describeTasks wasn't used to log task information.

core/src/main/java/org/elasticsearch/cluster/service/ClusterService.java

@@ -411,7 +411,8 @@ public class ClusterService extends AbstractLifecycleComponent {
                 List<UpdateTask> existingTasks = updateTasksPerExecutor.computeIfAbsent(executor, k -> new ArrayList<>());
                 for (@SuppressWarnings("unchecked") UpdateTask<T> existing : existingTasks) {
                     if (tasksIdentity.containsKey(existing.task)) {
-                        throw new IllegalStateException("task [" + existing.task + "] with source [" + source + "] is already queued");
+                        throw new IllegalStateException("task [" + executor.describeTasks(Collections.singletonList(existing.task)) +
+                            "] with source [" + source + "] is already queued");
                     }
                 }
                 existingTasks.addAll(updateTasks);
@@ -517,11 +518,11 @@ public class ClusterService extends AbstractLifecycleComponent {
             if (pending != null) {
                 for (UpdateTask<T> task : pending) {
                     if (task.processed.getAndSet(true) == false) {
-                        logger.trace("will process [{}[{}]]", task.source, task.task);
+                        logger.trace("will process {}", task.toString(executor));
                         toExecute.add(task);
                         processTasksBySource.computeIfAbsent(task.source, s -> new ArrayList<>()).add(task.task);
                     } else {
-                        logger.trace("skipping [{}[{}]], already processed", task.source, task.task);
+                        logger.trace("skipping {}, already processed", task.toString(executor));
                     }
                 }
             }
@@ -571,7 +572,8 @@ public class ClusterService extends AbstractLifecycleComponent {
         assert (assertsEnabled = true);
         if (assertsEnabled) {
             for (UpdateTask<T> updateTask : toExecute) {
-                assert batchResult.executionResults.containsKey(updateTask.task) : "missing task result for [" + updateTask.task + "]";
+                assert batchResult.executionResults.containsKey(updateTask.task) :
+                    "missing task result for " + updateTask.toString(executor);
             }
         }
 
@@ -579,13 +581,13 @@ public class ClusterService extends AbstractLifecycleComponent {
         final ArrayList<UpdateTask<T>> proccessedListeners = new ArrayList<>();
         // fail all tasks that have failed and extract those that are waiting for results
         for (UpdateTask<T> updateTask : toExecute) {
-            assert batchResult.executionResults.containsKey(updateTask.task) : "missing " + updateTask.task.toString();
+            assert batchResult.executionResults.containsKey(updateTask.task) : "missing " + updateTask.toString(executor);
             final ClusterStateTaskExecutor.TaskResult executionResult =
                     batchResult.executionResults.get(updateTask.task);
             executionResult.handle(
                     () -> proccessedListeners.add(updateTask),
                     ex -> {
-                        logger.debug("cluster state update task [{}] failed", ex, updateTask.source);
+                        logger.debug("cluster state update task {} failed", ex, updateTask.toString(executor));
                         updateTask.listener.onFailure(updateTask.source, ex);
                     }
             );
@@ -854,6 +856,15 @@ public class ClusterService extends AbstractLifecycleComponent {
         public void run() {
             runTasksForExecutor(executor);
         }
+
+        public String toString(ClusterStateTaskExecutor<T> executor) {
+            String taskDescription = executor.describeTasks(Collections.singletonList(task));
+            if (taskDescription.isEmpty()) {
+                return "[" + source + "]";
+            } else {
+                return "[" + source + "[" + taskDescription + "]]";
+            }
+        }
     }
 
     private void warnAboutSlowTaskIfNeeded(TimeValue executionTime, String source) {