Fix : Druid throws java.util.concurrent.RejectedExecutionException when ingest task is stopping. (#10555)

* check exec status before return Signal

* add more log

* change log level to debug and add UT

* change log leverl to warn and merge master

Co-authored-by: yuezhang <yuezhang@freewheel.tv>

core/src/main/java/org/apache/druid/java/util/common/concurrent/ScheduledExecutors.java

@@ -53,7 +53,12 @@ public class ScheduledExecutors
           public Signal call()
           {
             runnable.run(); // (Exceptions are handled for us)
-            return Signal.REPEAT;
+            if (exec.isShutdown()) {
+              log.warn("ScheduledExecutorService is ShutDown. Return 'Signal.STOP' and stopped rescheduling %s (delay %s)", this, delay);
+              return Signal.STOP;
+            } else {
+              return Signal.REPEAT;
+            }
           }
         }
     );

core/src/test/java/org/apache/druid/java/util/common/concurrent/ScheduledExecutorsTest.java

@@ -0,0 +1,46 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF 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.apache.druid.java.util.common.concurrent;
+
+import org.joda.time.Duration;
+import org.junit.Test;
+
+import java.util.concurrent.ScheduledExecutorService;
+
+public class ScheduledExecutorsTest
+{
+  @Test
+  public void testscheduleWithFixedDelay() throws InterruptedException
+  {
+    Duration initialDelay = new Duration(1000);
+    Duration delay = new Duration(1000);
+    ScheduledExecutorService exec = Execs.scheduledSingleThreaded("BasicAuthenticatorCacheManager-Exec--%d");
+    ScheduledExecutors.scheduleWithFixedDelay(
+            exec,
+            initialDelay,
+            delay,
+        () -> {
+            System.out.println("TEST!");
+        }
+    );
+    Thread.sleep(5 * 1000);
+    exec.shutdown();
+  }
+}