Stop AutoRepair monitoring thread upon Cassandra shutdown

patch by Jaydeepkumar Chovatia; reviewed by Bernardo Botella, Andrew Tolbert for CASSANDRA-20623

CHANGES.txt

@@ -1,4 +1,5 @@
 5.1
+ * Stop AutoRepair monitoring thread upon Cassandra shutdown (CASSANDRA-20623)
  * Avoid duplicate hardlink error upon forceful taking of ephemeral snapshots during repair (CASSANDRA-20490)
  * When a custom disk error handler fails to initiate, fail the startup of a node instead of using the no-op handler (CASSANDRA-20614)
  * Rewrite constraint framework to remove column specification from constraint definition, introduce SQL-like NOT NULL (CASSANDRA-20563)

src/java/org/apache/cassandra/repair/autorepair/AutoRepair.java

@@ -28,6 +28,7 @@ import java.util.List;
 import java.util.Map;
 import java.util.Set;
 import java.util.UUID;
+import java.util.concurrent.ExecutionException;
 import java.util.concurrent.TimeUnit;
 import java.util.function.BiConsumer;
 import java.util.function.Consumer;
@@ -102,6 +103,8 @@ public class AutoRepair
     public boolean isSetupDone = false;
     public static AutoRepair instance = new AutoRepair();
 
+    public volatile boolean isShutDown = false;
+
     private AutoRepair()
     {
         // Private constructor to prevent instantiation
@@ -566,4 +569,35 @@ public class AutoRepair
             }
         }
     }
+
+    public synchronized void shutdownBlocking() throws ExecutionException, InterruptedException
+    {
+        if (!isSetupDone)
+        {
+            // By default, executors within AutoRepair are not initialized as the feature is opt-in.
+            // If the AutoRepair has not been set up, then there is no need to worry about shutting it down
+            return;
+        }
+        if (isShutDown)
+        {
+            throw new IllegalStateException("AutoRepair has already been shut down");
+        }
+        isShutDown = true;
+        for (AutoRepairConfig.RepairType repairType : AutoRepairConfig.RepairType.values())
+        {
+            repairRunnableExecutors.get(repairType).shutdown();
+            repairExecutors.get(repairType).shutdown();
+        }
+        logger.info("Paused AutoRepair");
+    }
+
+    public Map<AutoRepairConfig.RepairType, ScheduledExecutorPlus> getRepairExecutors()
+    {
+        return repairExecutors;
+    }
+
+    public Map<AutoRepairConfig.RepairType, ScheduledExecutorPlus> getRepairRunnableExecutors()
+    {
+        return repairRunnableExecutors;
+    }
 }

src/java/org/apache/cassandra/service/StorageService.java

@@ -3913,6 +3913,8 @@ public class StorageService extends NotificationBroadcasterSupport implements IE
 
             CommitLog.instance.shutdownBlocking();
 
+            AutoRepair.instance.shutdownBlocking();
+
             // wait for miscellaneous tasks like sstable and commitlog segment deletion
             ColumnFamilyStore.shutdownPostFlushExecutor();
 

test/unit/org/apache/cassandra/repair/autorepair/AutoRepairShutdownTest.java

@@ -0,0 +1,75 @@
+/*
+ * 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.cassandra.repair.autorepair;
+
+import org.junit.BeforeClass;
+import org.junit.Test;
+
+import org.apache.cassandra.cql3.CQLTester;
+import org.apache.cassandra.repair.autorepair.AutoRepairConfig.RepairType;
+
+import static org.apache.cassandra.Util.setAutoRepairEnabled;
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertTrue;
+import static org.junit.Assert.fail;
+
+/**
+ * Unit tests to validate the executor shutdown inside {@link AutoRepair}
+ */
+public class AutoRepairShutdownTest extends CQLTester
+{
+    @BeforeClass
+    public static void setupClass() throws Exception
+    {
+        setAutoRepairEnabled(true);
+        requireNetwork();
+    }
+
+    @Test
+    public void testAutoRepairShutdown() throws Exception
+    {
+        AutoRepair.instance.setup();
+
+        for (RepairType type : RepairType.values())
+        {
+            assertFalse("RepairRunnableExecutor should not have been shut down", AutoRepair.instance.getRepairRunnableExecutors().get(type).isShutdown());
+            assertFalse("RepairExecutor should not have been shut down", AutoRepair.instance.getRepairExecutors().get(type).isShutdown());
+        }
+        assertFalse("AutoRepair should not be marked as shut down", AutoRepair.instance.isShutDown);
+
+        AutoRepair.instance.shutdownBlocking();
+
+        for (RepairType type : RepairType.values())
+        {
+            assertTrue("RepairRunnableExecutor should be shut down", AutoRepair.instance.getRepairRunnableExecutors().get(type).isShutdown());
+            assertTrue("RepairExecutor should be shut down", AutoRepair.instance.getRepairExecutors().get(type).isShutdown());
+        }
+        assertTrue("AutoRepair should be marked as shut down", AutoRepair.instance.isShutDown);
+
+        try
+        {
+            AutoRepair.instance.shutdownBlocking();
+            fail("A second call to shutdown should have thrown an exception");
+        }
+        catch (IllegalStateException e)
+        {
+            // expected
+        }
+    }
+}