server/src/main/java/org/apache/druid/server/coordinator/duty/KillCompactionConfig.java

/*
 * 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.druid.server.coordinator.duty;

import com.google.common.collect.ImmutableList;
import org.apache.druid.audit.AuditInfo;
import org.apache.druid.common.config.ConfigManager;
import org.apache.druid.java.util.RetryableException;
import org.apache.druid.java.util.common.RetryUtils;
import org.apache.druid.java.util.common.logger.Logger;
import org.apache.druid.metadata.SegmentsMetadataManager;
import org.apache.druid.server.coordinator.CoordinatorCompactionConfig;
import org.apache.druid.server.coordinator.CoordinatorConfigManager;
import org.apache.druid.server.coordinator.DataSourceCompactionConfig;
import org.apache.druid.server.coordinator.config.MetadataCleanupConfig;
import org.apache.druid.server.coordinator.stats.Stats;
import org.joda.time.DateTime;

import java.util.Map;
import java.util.Set;
import java.util.concurrent.atomic.AtomicInteger;
import java.util.function.Function;
import java.util.stream.Collectors;

/**
 * CoordinatorDuty for automatic deletion of compaction configurations from the config table in metadata storage.
 * Note that this will delete compaction configuration for inactive datasources
 * (datasource with no used and unused segments) immediately.
 */
public class KillCompactionConfig extends MetadataCleanupDuty
{
  private static final Logger log = new Logger(KillCompactionConfig.class);
  private static final int UPDATE_NUM_RETRY = 5;

  private final SegmentsMetadataManager sqlSegmentsMetadataManager;
  private final CoordinatorConfigManager configManager;

  public KillCompactionConfig(
      MetadataCleanupConfig config,
      SegmentsMetadataManager sqlSegmentsMetadataManager,
      CoordinatorConfigManager configManager
  )
  {
    super("compaction configs", config, Stats.Kill.COMPACTION_CONFIGS);
    this.sqlSegmentsMetadataManager = sqlSegmentsMetadataManager;
    this.configManager = configManager;
  }

  @Override
  protected int cleanupEntriesCreatedBefore(DateTime minCreatedTime)
  {
    try {
      return RetryUtils.retry(
          this::tryDeleteCompactionConfigs,
          e -> e instanceof RetryableException,
          UPDATE_NUM_RETRY
      );
    }
    catch (Exception e) {
      log.error(e, "Failed to kill compaction configurations");
      return 0;
    }
  }

  /**
   * Creates a new compaction config by deleting entries for inactive datasources.
   */
  private CoordinatorCompactionConfig deleteConfigsForInactiveDatasources(
      CoordinatorCompactionConfig current
  )
  {
    // If current compaction config is empty then there is nothing to do
    if (CoordinatorCompactionConfig.empty().equals(current)) {
      log.info("Nothing to do as compaction config is already empty.");
      return current;
    }

    // Get all active datasources
    // Note that we get all active datasources after getting compaction config to prevent race condition if new
    // datasource and config are added.
    Set<String> activeDatasources = sqlSegmentsMetadataManager.retrieveAllDataSourceNames();
    final Map<String, DataSourceCompactionConfig> updated = current
        .getCompactionConfigs()
        .stream()
        .filter(dataSourceCompactionConfig -> activeDatasources.contains(dataSourceCompactionConfig.getDataSource()))
        .collect(Collectors.toMap(DataSourceCompactionConfig::getDataSource, Function.identity()));

    return CoordinatorCompactionConfig.from(current, ImmutableList.copyOf(updated.values()));
  }

  /**
   * Tries to delete compaction configs for inactive datasources and returns
   * the number of compaction configs successfully removed.
   */
  private int tryDeleteCompactionConfigs() throws RetryableException
  {
    // Calculate number of compaction configs removed
    final AtomicInteger compactionConfigRemoved = new AtomicInteger(0);

    ConfigManager.SetResult result = configManager.getAndUpdateCompactionConfig(
        current -> {
          final CoordinatorCompactionConfig updated = deleteConfigsForInactiveDatasources(current);
          int numCurrentConfigs = current.getCompactionConfigs() == null ? 0 : current.getCompactionConfigs().size();
          int numUpdatedConfigs = updated.getCompactionConfigs() == null ? 0 : updated.getCompactionConfigs().size();
          compactionConfigRemoved.set(Math.max(0, numCurrentConfigs - numUpdatedConfigs));

          return updated;
        },
        new AuditInfo(
            "KillCompactionConfig",
            "KillCompactionConfig",
            "CoordinatorDuty for automatic deletion of compaction config",
            ""
        )
    );

    if (result.isOk()) {
      return compactionConfigRemoved.get();
    } else if (result.isRetryable()) {
      log.debug("Retrying KillCompactionConfig duty");
      throw new RetryableException(result.getException());
    } else {
      log.error(result.getException(), "Failed to kill compaction configurations");
      return 0;
    }
  }
}