Fix bug where topology query could execute indefinitely

wrapper/src/main/java/software/amazon/jdbc/hostlistprovider/AuroraHostListProvider.java

@@ -30,6 +30,7 @@
 import java.util.Properties;
 import java.util.Set;
 import java.util.UUID;
+import java.util.concurrent.Executor;
 import java.util.concurrent.TimeUnit;
 import java.util.concurrent.locks.ReentrantLock;
 import java.util.logging.Logger;
@@ -48,6 +49,7 @@
 import software.amazon.jdbc.util.RdsUrlType;
 import software.amazon.jdbc.util.RdsUtils;
 import software.amazon.jdbc.util.StringUtils;
+import software.amazon.jdbc.util.SynchronousExecutor;
 import software.amazon.jdbc.util.Utils;
 
 public class AuroraHostListProvider implements DynamicHostListProvider {
@@ -75,6 +77,7 @@ public class AuroraHostListProvider implements DynamicHostListProvider {
               + "This pattern is required to be specified for IP address or custom domain connections to AWS RDS "
               + "clusters. Otherwise, if unspecified, the pattern will be automatically created for AWS RDS clusters.");
 
+  private final Executor networkTimeoutExecutor = new SynchronousExecutor();
   private final HostListProviderService hostListProviderService;
   private final String originalUrl;
   private RdsUrlType rdsUrlType;
@@ -93,6 +96,7 @@ public class AuroraHostListProvider implements DynamicHostListProvider {
   public static final CacheMap<String, String> suggestedPrimaryClusterIdCache = new CacheMap<>();
   public static final CacheMap<String, Boolean> primaryClusterIdCache = new CacheMap<>();
 
+  private static final int defaultTopologyQueryTimeoutMs = 5000;
   private final ReentrantLock lock = new ReentrantLock();
   protected String clusterId;
   protected HostSpec clusterInstanceTemplate;
@@ -333,11 +337,27 @@ protected List<HostSpec> queryForTopology(final Connection conn) throws SQLExcep
       this.topologyAwareDialect = (TopologyAwareDatabaseCluster) this.hostListProviderService.getDialect();
     }
 
+    int networkTimeout = -1;
+    try {
+      networkTimeout = conn.getNetworkTimeout();
+      // The topology query is not monitored by the EFM plugin, so it needs a socket timeout
+      if (networkTimeout == 0) {
+        conn.setNetworkTimeout(networkTimeoutExecutor, defaultTopologyQueryTimeoutMs);
+      }
+    } catch (SQLException e) {
+      LOGGER.warning(() -> Messages.get("AuroraHostListProvider.errorGettingNetworkTimeout",
+          new Object[] {e.getMessage()}));
+    }
+
     try (final Statement stmt = conn.createStatement();
         final ResultSet resultSet = stmt.executeQuery(this.topologyAwareDialect.getTopologyQuery())) {
       return processQueryResults(resultSet);
     } catch (final SQLSyntaxErrorException e) {
       throw new SQLException(Messages.get("AuroraHostListProvider.invalidQuery"), e);
+    } finally {
+      if (networkTimeout == 0 && !conn.isClosed()) {
+        conn.setNetworkTimeout(networkTimeoutExecutor, networkTimeout);
+      }
     }
   }
 

wrapper/src/main/java/software/amazon/jdbc/util/SynchronousExecutor.java

@@ -0,0 +1,28 @@
+/*
+ * Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
+ *
+ * Licensed 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 software.amazon.jdbc.util;
+
+import java.io.Serializable;
+import java.util.concurrent.Executor;
+
+public class SynchronousExecutor implements Executor, Serializable {
+
+  @Override
+  public void execute(Runnable task) {
+    task.run();
+  }
+}

wrapper/src/main/resources/messages.properties

@@ -28,6 +28,7 @@ AuroraHostListProvider.invalidQuery=Error obtaining host list. Provided database
 AuroraHostListProvider.invalidDialect=Expecting a dialect that supports a cluster topology.
 AuroraHostListProvider.invalidDialectForGetHostRole=An Aurora dialect is required to analyze a host's role. The detected dialect was ''{0}''
 AuroraHostListProvider.errorGettingHostRole=An error occurred while obtaining the connected host's role. This could occur if the connection is broken or if you are not connected to an Aurora database.
+AuroraHostListProvider.errorGettingNetworkTimeout=An error occurred while getting the connection network timeout: {0}
 
 # AWS Credentials Manager
 AwsCredentialsManager.nullProvider=The configured AwsCredentialsProvider was null. If you have configured the AwsCredentialsManager to use a custom AwsCredentialsProviderHandler, please ensure the handler does not return null.