content: /*
   * 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.bifromq.basekv.localengine.rocksdb;
  
  import org.apache.bifromq.basekv.localengine.KVEngineException;
  import org.apache.bifromq.basekv.localengine.metrics.KVSpaceOpMeters;
  import io.micrometer.core.instrument.Gauge;
  import io.micrometer.core.instrument.Metrics;
  import io.micrometer.core.instrument.Tags;
  import java.io.File;
  import java.nio.file.Files;
  import org.slf4j.Logger;
  
  public class RocksDBCPableKVEngine extends
      RocksDBKVEngine<RocksDBCPableKVEngine, RocksDBCPableKVSpace, RocksDBCPableKVEngineConfigurator> {
      private final File cpRootDir;
      private MetricManager metricManager;
  
      public RocksDBCPableKVEngine(String overrideIdentity,
                                   RocksDBCPableKVEngineConfigurator configurator) {
          super(overrideIdentity, configurator);
          cpRootDir = new File(configurator.dbCheckpointRootDir());
          try {
              Files.createDirectories(cpRootDir.getAbsoluteFile().toPath());
          } catch (Throwable e) {
              throw new KVEngineException("Failed to create checkpoint root folder", e);
          }
      }
  
      @Override
      protected RocksDBCPableKVSpace doBuildKVSpace(String spaceId,
                                                    RocksDBCPableKVEngineConfigurator configurator,
                                                    Runnable onDestroy,
                                                    KVSpaceOpMeters opMeters,
                                                    Logger logger,
                                                    String... tags) {
          return new RocksDBCPableKVSpace(spaceId, configurator, this, onDestroy, opMeters, logger, tags);
      }
  
      @Override
      protected void doStart(String... metricTags) {
          super.doStart(metricTags);
          metricManager = new MetricManager(metricTags);
      }
  
      @Override
      protected void doStop() {
          metricManager.close();
          super.doStop();
      }
  
      private class MetricManager {
          private final Gauge checkpointTotalSpaceGauge;
          private final Gauge checkpointsUsableSpaceGauge;
  
          MetricManager(String... metricTags) {
              Tags tags = Tags.of(metricTags);
              checkpointTotalSpaceGauge =
                  Gauge.builder("basekv.le.rocksdb.total.checkpoints", cpRootDir::getTotalSpace)
                      .tags(tags)
                      .register(Metrics.globalRegistry);
              checkpointsUsableSpaceGauge = Gauge.builder("basekv.le.rocksdb.usable.checkpoints",
                      cpRootDir::getUsableSpace)
                  .tags(tags)
                  .register(Metrics.globalRegistry);
          }
  
          void close() {
              Metrics.globalRegistry.remove(checkpointTotalSpaceGauge);
              Metrics.globalRegistry.remove(checkpointsUsableSpaceGauge);
          }
      }
  }
  