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.base.Preconditions;
import com.google.common.collect.ImmutableList;
import com.google.inject.Inject;
import org.apache.druid.audit.AuditInfo;
import org.apache.druid.common.config.ConfigManager;
import org.apache.druid.common.config.JacksonConfigManager;
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.java.util.emitter.service.ServiceEmitter;
import org.apache.druid.java.util.emitter.service.ServiceMetricEvent;
import org.apache.druid.metadata.SqlSegmentsMetadataManager;
import org.apache.druid.server.coordinator.CoordinatorCompactionConfig;
import org.apache.druid.server.coordinator.DataSourceCompactionConfig;
import org.apache.druid.server.coordinator.DruidCoordinatorConfig;
import org.apache.druid.server.coordinator.DruidCoordinatorRuntimeParams;

import java.util.Map;
import java.util.Set;
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 implements CoordinatorDuty
{
  private static final Logger log = new Logger(KillCompactionConfig.class);
  private static final int UPDATE_NUM_RETRY = 5;

  static final String COUNT_METRIC = "metadata/kill/compaction/count";

  private final long period;
  private long lastKillTime = 0;

  private final JacksonConfigManager jacksonConfigManager;
  private final SqlSegmentsMetadataManager sqlSegmentsMetadataManager;

  @Inject
  public KillCompactionConfig(
      DruidCoordinatorConfig config,
      SqlSegmentsMetadataManager sqlSegmentsMetadataManager,
      JacksonConfigManager jacksonConfigManager
  )
  {
    this.sqlSegmentsMetadataManager = sqlSegmentsMetadataManager;
    this.jacksonConfigManager = jacksonConfigManager;
    this.period = config.getCoordinatorCompactionKillPeriod().getMillis();
    Preconditions.checkArgument(
        this.period >= config.getCoordinatorMetadataStoreManagementPeriod().getMillis(),
        "Coordinator compaction configuration kill period must be >= druid.coordinator.period.metadataStoreManagementPeriod"
    );
    log.debug(
        "Compaction Configuration Kill Task scheduling enabled with period [%s]",
        this.period
    );
  }

  @Override
  public DruidCoordinatorRuntimeParams run(DruidCoordinatorRuntimeParams params)
  {
    long currentTimeMillis = System.currentTimeMillis();
    if ((lastKillTime + period) < currentTimeMillis) {
      lastKillTime = currentTimeMillis;
      try {
        RetryUtils.retry(
            () -> {
              CoordinatorCompactionConfig current = CoordinatorCompactionConfig.current(jacksonConfigManager);
              // If current compaction config is empty then there is nothing to do
              if (CoordinatorCompactionConfig.empty().equals(current)) {
                log.info(
                    "Finished running KillCompactionConfig duty. Nothing to do as compaction config is already empty.");
                emitMetric(params.getEmitter(), 0);
                return ConfigManager.SetResult.ok();
              }

              // 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()));

              // Calculate number of compaction configs to remove for logging
              int compactionConfigRemoved = current.getCompactionConfigs().size() - updated.size();

              ConfigManager.SetResult result = jacksonConfigManager.set(
                  CoordinatorCompactionConfig.CONFIG_KEY,
                  // Do database insert without swap if the current config is empty as this means the config may be null in the database
                  current,
                  CoordinatorCompactionConfig.from(current, ImmutableList.copyOf(updated.values())),
                  new AuditInfo(
                      "KillCompactionConfig",
                      "CoordinatorDuty for automatic deletion of compaction config",
                      ""
                  )
              );
              if (result.isOk()) {
                log.info(
                    "Finished running KillCompactionConfig duty. Removed %,d compaction configs",
                    compactionConfigRemoved
                );
                emitMetric(params.getEmitter(), compactionConfigRemoved);
              } else if (result.isRetryable()) {
                // Failed but is retryable
                log.debug("Retrying KillCompactionConfig duty");
                throw new RetryableException(result.getException());
              } else {
                // Failed and not retryable
                log.error(result.getException(), "Failed to kill compaction configurations");
                emitMetric(params.getEmitter(), 0);
              }
              return result;
            },
            e -> e instanceof RetryableException,
            UPDATE_NUM_RETRY
        );
      }
      catch (Exception e) {
        log.error(e, "Failed to kill compaction configurations");
        emitMetric(params.getEmitter(), 0);
      }
    }
    return params;
  }

  private void emitMetric(ServiceEmitter emitter, int compactionConfigRemoved)
  {
    emitter.emit(
        new ServiceMetricEvent.Builder().build(
            COUNT_METRIC,
            compactionConfigRemoved
        )
    );
  }
}