This closes #3056

artemis-server/src/main/java/org/apache/activemq/artemis/core/server/impl/BackupRecoveryJournalLoader.java

@@ -50,6 +50,7 @@ public class BackupRecoveryJournalLoader extends PostOfficeJournalLoader {
    private ServerLocator locator;
    private final ClusterController clusterController;
    private final StorageManager storageManager;
+   private final Configuration configuration;
 
    public BackupRecoveryJournalLoader(PostOffice postOffice,
                                       PagingManager pagingManager,
@@ -68,6 +69,7 @@ public class BackupRecoveryJournalLoader extends PostOfficeJournalLoader {
       this.locator = locator;
       this.clusterController = clusterController;
       this.storageManager = storageManager;
+      this.configuration = configuration;
    }
 
    @Override
@@ -89,11 +91,11 @@ public class BackupRecoveryJournalLoader extends PostOfficeJournalLoader {
    public void postLoad(Journal messageJournal,
                         ResourceManager resourceManager,
                         Map<SimpleString, List<Pair<byte[], Long>>> duplicateIDMap) throws Exception {
-      ScaleDownHandler scaleDownHandler = new ScaleDownHandler(pagingManager, postOffice, nodeManager, clusterController, parentServer.getStorageManager());
+      ScaleDownHandler scaleDownHandler = new ScaleDownHandler(pagingManager, postOffice, nodeManager, clusterController, parentServer != null ? parentServer.getStorageManager() : storageManager);
       locator.setProtocolManagerFactory(ActiveMQServerSideProtocolManagerFactory.getInstance(locator, storageManager));
 
       try (ClientSessionFactory sessionFactory = locator.createSessionFactory()) {
-         scaleDownHandler.scaleDown(sessionFactory, resourceManager, duplicateIDMap, parentServer.getConfiguration().getManagementAddress(), parentServer.getNodeID());
+         scaleDownHandler.scaleDown(sessionFactory, resourceManager, duplicateIDMap, parentServer != null ? parentServer.getConfiguration().getManagementAddress() : configuration.getManagementAddress(), parentServer != null ? parentServer.getNodeID() : null);
       }
    }
 

tests/integration-tests/src/test/java/org/apache/activemq/artemis/tests/integration/cluster/failover/SharedStoreScaleDownBackupTest.java

@@ -0,0 +1,126 @@
+/**
+ * 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
+ * <p>
+ * http://www.apache.org/licenses/LICENSE-2.0
+ * <p>
+ * 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.activemq.artemis.tests.integration.cluster.failover;
+
+import org.apache.activemq.artemis.api.core.SimpleString;
+import org.apache.activemq.artemis.api.core.client.ClientMessage;
+import org.apache.activemq.artemis.core.config.ScaleDownConfiguration;
+import org.apache.activemq.artemis.core.config.ha.SharedStoreMasterPolicyConfiguration;
+import org.apache.activemq.artemis.core.config.ha.SharedStoreSlavePolicyConfiguration;
+import org.apache.activemq.artemis.core.postoffice.impl.LocalQueueBinding;
+import org.apache.activemq.artemis.core.server.cluster.impl.MessageLoadBalancingType;
+import org.apache.activemq.artemis.core.settings.impl.AddressSettings;
+import org.apache.activemq.artemis.tests.integration.cluster.distribution.ClusterTestBase;
+import org.junit.Assert;
+import org.junit.Before;
+import org.junit.Test;
+
+public class SharedStoreScaleDownBackupTest extends ClusterTestBase {
+
+   protected boolean isNetty() {
+      return true;
+   }
+
+   @Override
+   @Before
+   public void setUp() throws Exception {
+      super.setUp();
+
+      setupLiveServer(0, isFileStorage(), true, isNetty(), false);
+      setupLiveServer(1, isFileStorage(), true, isNetty(), false);
+      setupBackupServer(2, 0, isFileStorage(), true, isNetty());
+
+      setupClusterConnection("cluster0", "testAddress", MessageLoadBalancingType.ON_DEMAND, 1, isNetty(), 0, 1);
+      setupClusterConnection("cluster1", "testAddress", MessageLoadBalancingType.ON_DEMAND, 1, isNetty(), 1, 0);
+      setupClusterConnection("cluster0", "testAddress", MessageLoadBalancingType.ON_DEMAND, 1, isNetty(), 2, 1);
+
+      ((SharedStoreMasterPolicyConfiguration)getServer(0).getConfiguration().getHAPolicyConfiguration()).
+         setFailoverOnServerShutdown(true);
+      ((SharedStoreSlavePolicyConfiguration)getServer(2).getConfiguration().getHAPolicyConfiguration()).
+         setFailoverOnServerShutdown(true).
+         setRestartBackup(true).
+         setScaleDownConfiguration(new ScaleDownConfiguration().setEnabled(true).addConnector(
+            getServer(2).getConfiguration().getClusterConfigurations().get(0).getStaticConnectors().get(0)));
+
+      getServer(0).getConfiguration().getAddressesSettings().put("#", new AddressSettings().setRedistributionDelay(0));
+      getServer(1).getConfiguration().getAddressesSettings().put("#", new AddressSettings().setRedistributionDelay(0));
+
+      startServers(0, 1, 2);
+
+      setupSessionFactory(0, isNetty());
+      setupSessionFactory(1, isNetty());
+   }
+
+
+   @Test
+   public void testBasicScaleDown() throws Exception {
+      final int TEST_SIZE = 2;
+      final String addressName = "testAddress";
+      final String queueName1 = "testQueue1";
+      final String queueName2 = "testQueue2";
+
+      // create 2 queues on each node mapped to the same address
+      createQueue(0, addressName, queueName1, null, true);
+      createQueue(0, addressName, queueName2, null, true);
+      createQueue(1, addressName, queueName1, null, true);
+      createQueue(1, addressName, queueName2, null, true);
+
+      // send messages to node 0
+      send(0, addressName, TEST_SIZE, true, null);
+
+      // consume a message from queue 2
+      addConsumer(1, 0, queueName2, null, false);
+      ClientMessage clientMessage = consumers[1].getConsumer().receive(250);
+      Assert.assertNotNull(clientMessage);
+      clientMessage.acknowledge();
+      consumers[1].getSession().commit();
+      //      removeConsumer(1);
+
+      // at this point on node 0 there should be 2 messages in testQueue1 and 1 message in testQueue2
+      Assert.assertEquals(TEST_SIZE, getMessageCount(((LocalQueueBinding) servers[0].getPostOffice().getBinding(new SimpleString(queueName1))).getQueue()));
+      Assert.assertEquals(TEST_SIZE - 1, getMessageCount(((LocalQueueBinding) servers[0].getPostOffice().getBinding(new SimpleString(queueName2))).getQueue()));
+
+      // trigger scaleDown from node 0 to node 1
+      servers[0].stop();
+
+      // get the 2 messages from queue 1
+      addConsumer(0, 1, queueName1, null);
+      clientMessage = consumers[0].getConsumer().receive(250);
+      Assert.assertNotNull(clientMessage);
+      clientMessage.acknowledge();
+      clientMessage = consumers[0].getConsumer().receive(250);
+      Assert.assertNotNull(clientMessage);
+      clientMessage.acknowledge();
+
+      // ensure there are no more messages on queue 1
+      clientMessage = consumers[0].getConsumer().receive(250);
+      Assert.assertNull(clientMessage);
+      removeConsumer(0);
+
+      // get the 1 message from queue 2
+      addConsumer(0, 1, queueName2, null);
+      clientMessage = consumers[0].getConsumer().receive(250);
+      Assert.assertNotNull(clientMessage);
+      clientMessage.acknowledge();
+
+      // ensure there are no more messages on queue 1
+      clientMessage = consumers[0].getConsumer().receive(250);
+      Assert.assertNull(clientMessage);
+      removeConsumer(0);
+   }
+}