server/src/main/java/org/apache/druid/indexing/overlord/supervisor/NoopSupervisorSpec.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.indexing.overlord.supervisor;

import com.fasterxml.jackson.annotation.JsonCreator;
import com.fasterxml.jackson.annotation.JsonIgnore;
import com.fasterxml.jackson.annotation.JsonProperty;
import com.google.common.annotations.VisibleForTesting;
import com.google.common.collect.ImmutableSet;
import org.apache.druid.indexing.overlord.DataSourceMetadata;
import org.apache.druid.indexing.overlord.supervisor.autoscaler.LagStats;
import org.apache.druid.server.security.ResourceAction;

import javax.annotation.Nonnull;
import javax.annotation.Nullable;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import java.util.Objects;
import java.util.Set;

/**
 * Used as a tombstone marker in the supervisors metadata table to indicate that the supervisor has been removed.
 */
public class NoopSupervisorSpec implements SupervisorSpec
{
  // NoopSupervisorSpec is used as a tombstone, added when a previously running supervisor is stopped.
  // Inherit the datasources of the previous running spec, so that we can determine whether a user is authorized to see
  // this tombstone (users can only see tombstones for datasources that they have access to).
  @Nullable
  @JsonProperty("dataSources")
  private List<String> datasources;

  @Nullable
  @JsonProperty("id")
  private String id;

  @JsonProperty("suspended")
  private boolean suspended; //ignored

  @JsonProperty("type")
  private String type; //ignored

  @JsonProperty("source")
  private String source; //ignored

  @VisibleForTesting
  public NoopSupervisorSpec(
      String id,
      List<String> datasources
  )
  {
    this(id, datasources, null, null, null);
  }

  @JsonCreator
  public NoopSupervisorSpec(
      @JsonProperty("id") @Nullable String id,
      @JsonProperty("dataSources") @Nullable List<String> datasources,
      @JsonProperty("suspended") @Nullable Boolean suspended,
      @JsonProperty("type") @Nullable String type,
      @JsonProperty("source") @Nullable String source
  )
  {
    this.id = id;
    this.datasources = datasources == null ? new ArrayList<>() : datasources;
    // these are ignored
    this.suspended = false;
    this.type = "noop";
    this.source = "noop";
  }

  @Override
  @JsonProperty
  public String getId()
  {
    return id;
  }


  @Override
  @Nullable
  @JsonProperty("dataSources")
  public List<String> getDataSources()
  {
    return datasources;
  }

  @Override
  @JsonProperty("suspended")
  public boolean isSuspended()
  {
    return suspended;
  }

  @Override
  @JsonProperty("type")
  public String getType()
  {
    return type;
  }

  @Nonnull
  @JsonIgnore
  @Override
  public Set<ResourceAction> getInputSourceResources()
  {
    return ImmutableSet.of();
  }

  @Override
  @JsonProperty("source")
  public String getSource()
  {
    return source;
  }

  @Override
  public Supervisor createSupervisor()
  {
    return new Supervisor()
    {
      @Override
      public void start()
      {
      }

      @Override
      public void stop(boolean stopGracefully)
      {
      }

      @Override
      public SupervisorReport getStatus()
      {
        return null;
      }

      @Override
      public SupervisorStateManager.State getState()
      {
        return SupervisorStateManager.BasicState.RUNNING;
      }

      @Override
      public void reset(DataSourceMetadata dataSourceMetadata)
      {
      }

      @Override
      public void resetOffsets(DataSourceMetadata resetDataSourceMetadata)
      {
      }

      @Override
      public void checkpoint(int taskGroupId, DataSourceMetadata checkpointMetadata)
      {

      }

      @Override
      public LagStats computeLagStats()
      {
        return new LagStats(0, 0, 0);
      }

      @Override
      public int getActiveTaskGroupsCount()
      {
        return -1;
      }

      @Override
      public Set<String> getActiveRealtimeSequencePrefixes()
      {
        return Collections.emptySet();
      }
    };
  }

  @Override
  public SupervisorSpec createRunningSpec()
  {
    return new NoopSupervisorSpec(id, datasources);
  }

  @Override
  public SupervisorSpec createSuspendedSpec()
  {
    return new NoopSupervisorSpec(id, datasources);
  }

  @Override
  public boolean equals(Object o)
  {
    if (this == o) {
      return true;
    }
    if (o == null || getClass() != o.getClass()) {
      return false;
    }
    NoopSupervisorSpec spec = (NoopSupervisorSpec) o;
    return Objects.equals(datasources, spec.datasources) &&
           Objects.equals(getId(), spec.getId());
  }

  @Override
  public int hashCode()
  {
    return Objects.hash(datasources, getId());
  }
}