Refactor into appropriate uses of scheduleUnlessShuttingDown (#37709)

Replace `threadPool().schedule()` / catch
`EsRejectedExecutionException` pattern with direct calls to
`ThreadPool#scheduleUnlessShuttingDown()`.

Closes #36318

server/src/main/java/org/elasticsearch/cluster/InternalClusterInfoService.java

@@ -130,17 +130,17 @@ public class InternalClusterInfoService implements ClusterInfoService, LocalNode
         if (logger.isTraceEnabled()) {
             logger.trace("I have been elected master, scheduling a ClusterInfoUpdateJob");
         }
+
+        // Submit a job that will start after DEFAULT_STARTING_INTERVAL, and reschedule itself after running
+        threadPool.scheduleUnlessShuttingDown(updateFrequency, executorName(), new SubmitReschedulingClusterInfoUpdatedJob());
+
         try {
-            // Submit a job that will start after DEFAULT_STARTING_INTERVAL, and reschedule itself after running
-            threadPool.schedule(updateFrequency, executorName(), new SubmitReschedulingClusterInfoUpdatedJob());
             if (clusterService.state().getNodes().getDataNodes().size() > 1) {
                 // Submit an info update job to be run immediately
                 threadPool.executor(executorName()).execute(() -> maybeRefresh());
             }
         } catch (EsRejectedExecutionException ex) {
-            if (logger.isDebugEnabled()) {
-                logger.debug("Couldn't schedule cluster info update task - node might be shutting down", ex);
-            }
+            logger.debug("Couldn't schedule cluster info update task - node might be shutting down", ex);
         }
     }
 
@@ -223,11 +223,7 @@ public class InternalClusterInfoService implements ClusterInfoService, LocalNode
                             if (logger.isTraceEnabled()) {
                                 logger.trace("Scheduling next run for updating cluster info in: {}", updateFrequency.toString());
                             }
-                            try {
-                                threadPool.schedule(updateFrequency, executorName(), this);
-                            } catch (EsRejectedExecutionException ex) {
-                                logger.debug("Reschedule cluster info service was rejected", ex);
-                            }
+                            threadPool.scheduleUnlessShuttingDown(updateFrequency, executorName(), this);
                         }
                     }
                 });

server/src/main/java/org/elasticsearch/transport/TransportKeepAlive.java

@@ -30,7 +30,6 @@ import org.elasticsearch.common.metrics.CounterMetric;
 import org.elasticsearch.common.unit.TimeValue;
 import org.elasticsearch.common.util.concurrent.AbstractLifecycleRunnable;
 import org.elasticsearch.common.util.concurrent.ConcurrentCollections;
-import org.elasticsearch.common.util.concurrent.EsRejectedExecutionException;
 import org.elasticsearch.threadpool.ThreadPool;
 
 import java.io.Closeable;
@@ -185,15 +184,7 @@ final class TransportKeepAlive implements Closeable {
 
         @Override
         protected void onAfterInLifecycle() {
-            try {
-                threadPool.schedule(pingInterval, ThreadPool.Names.GENERIC, this);
-            } catch (EsRejectedExecutionException ex) {
-                if (ex.isExecutorShutdown()) {
-                    logger.debug("couldn't schedule new ping execution, executor is shutting down", ex);
-                } else {
-                    throw ex;
-                }
-            }
+            threadPool.scheduleUnlessShuttingDown(pingInterval, ThreadPool.Names.GENERIC, this);
         }
 
         @Override

x-pack/plugin/ccr/src/main/java/org/elasticsearch/xpack/ccr/action/ShardFollowTasksExecutor.java

@@ -32,7 +32,6 @@ import org.elasticsearch.common.settings.IndexScopedSettings;
 import org.elasticsearch.common.settings.Settings;
 import org.elasticsearch.common.settings.SettingsModule;
 import org.elasticsearch.common.unit.TimeValue;
-import org.elasticsearch.common.util.concurrent.EsRejectedExecutionException;
 import org.elasticsearch.index.Index;
 import org.elasticsearch.index.IndexNotFoundException;
 import org.elasticsearch.index.engine.CommitStats;
@@ -102,17 +101,8 @@ public class ShardFollowTasksExecutor extends PersistentTasksExecutor<ShardFollo
                                                  Map<String, String> headers) {
         ShardFollowTask params = taskInProgress.getParams();
         Client followerClient = wrapClient(client, params.getHeaders());
-        BiConsumer<TimeValue, Runnable> scheduler = (delay, command) -> {
-            try {
-                threadPool.schedule(delay, Ccr.CCR_THREAD_POOL_NAME, command);
-            } catch (EsRejectedExecutionException e) {
-                if (e.isExecutorShutdown()) {
-                    logger.debug("couldn't schedule command, executor is shutting down", e);
-                } else {
-                    throw e;
-                }
-            }
-        };
+        BiConsumer<TimeValue, Runnable> scheduler = (delay, command) ->
+            threadPool.scheduleUnlessShuttingDown(delay, Ccr.CCR_THREAD_POOL_NAME, command);
 
         final String recordedLeaderShardHistoryUUID = getLeaderShardHistoryUUID(params);
         return new ShardFollowNodeTask(id, type, action, getDescription(taskInProgress), parentTaskId, headers, params,