| /* |
| * 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.sidecar.routes; |
| |
| import java.util.function.Supplier; |
| |
| import javax.annotation.Nullable; |
| |
| import com.datastax.driver.core.ResultSet; |
| import com.datastax.driver.core.exceptions.NoHostAvailableException; |
| import com.google.inject.Inject; |
| import com.google.inject.Singleton; |
| import io.vertx.core.logging.Logger; |
| import io.vertx.core.logging.LoggerFactory; |
| import org.apache.cassandra.sidecar.CQLSession; |
| |
| /** |
| * Basic health check to verify that a CQL connection can be established with a basic SELECT query. |
| */ |
| @Singleton |
| public class HealthCheck implements Supplier<Boolean> |
| { |
| private static final Logger logger = LoggerFactory.getLogger(HealthCheck.class); |
| |
| @Nullable |
| private final CQLSession session; |
| |
| @Inject |
| public HealthCheck(@Nullable CQLSession session) |
| { |
| this.session = session; |
| } |
| |
| /** |
| * The actual health check |
| * |
| * @return |
| */ |
| private boolean check() |
| { |
| try |
| { |
| if (session != null && session.getLocalCql() != null) |
| { |
| ResultSet rs = session.getLocalCql().execute("SELECT release_version FROM system.local"); |
| boolean result = (rs.one() != null); |
| logger.debug("HealthCheck status: {}", result); |
| return result; |
| } |
| } |
| catch (NoHostAvailableException nha) |
| { |
| logger.trace("NoHostAvailableException in HealthCheck - Cassandra Down"); |
| } |
| catch (Exception e) |
| { |
| logger.error("Failed to reach Cassandra.", e); |
| } |
| return false; |
| } |
| |
| /** |
| * Get the check value |
| * |
| * @return true or false based on whether check was successful |
| */ |
| @Override |
| public Boolean get() |
| { |
| return check(); |
| } |
| |
| } |