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.bookkeeper.stream.storage.impl.metadata;
  
  import com.google.common.collect.Maps;
  import java.util.Map;
  import java.util.concurrent.CompletableFuture;
  import java.util.concurrent.ScheduledExecutorService;
  import lombok.extern.slf4j.Slf4j;
  import org.apache.bookkeeper.clients.impl.internal.api.StorageServerClientManager;
  import org.apache.bookkeeper.common.concurrent.FutureUtils;
  import org.apache.bookkeeper.statelib.api.mvcc.MVCCAsyncStore;
  import org.apache.bookkeeper.stream.proto.RangeMetadata;
  import org.apache.bookkeeper.stream.proto.StreamProperties;
  import org.apache.bookkeeper.stream.proto.storage.GetActiveRangesRequest;
  import org.apache.bookkeeper.stream.proto.storage.GetActiveRangesResponse;
  import org.apache.bookkeeper.stream.proto.storage.RelatedRanges;
  import org.apache.bookkeeper.stream.proto.storage.RelationType;
  import org.apache.bookkeeper.stream.proto.storage.StatusCode;
  import org.apache.bookkeeper.stream.protocol.util.StorageContainerPlacementPolicy;
  import org.apache.bookkeeper.stream.storage.api.metadata.MetaRangeStore;
  import org.apache.bookkeeper.stream.storage.api.metadata.stream.MetaRange;
  import org.apache.bookkeeper.stream.storage.impl.metadata.stream.MetaRangeImpl;
  
  /**
   * The default implementation of {@link MetaRangeStore}.
   */
  @Slf4j
  public class MetaRangeStoreImpl
      implements MetaRangeStore {
  
      private final MVCCAsyncStore<byte[], byte[]> store;
      private final ScheduledExecutorService executor;
      private final StorageContainerPlacementPolicy rangePlacementPolicy;
      private final Map<Long, MetaRangeImpl> streams;
      private final StorageServerClientManager clientManager;
  
      public MetaRangeStoreImpl(MVCCAsyncStore<byte[], byte[]> store,
                                StorageContainerPlacementPolicy rangePlacementPolicy,
                                ScheduledExecutorService executor,
                                StorageServerClientManager clientManager) {
          this.store = store;
          this.executor = executor;
          this.rangePlacementPolicy = rangePlacementPolicy;
          this.streams = Maps.newHashMap();
          this.clientManager = clientManager;
      }
  
      //
      // Methods for {@link MetaRangeStore}
      //
  
      //
      // Stream API
      //
  
      private CompletableFuture<GetActiveRangesResponse> createStreamIfMissing(long streamId,
                                                                               MetaRangeImpl metaRange,
                                                                               StreamProperties streamProps) {
          if (null == streamProps) {
              return FutureUtils.value(GetActiveRangesResponse.newBuilder()
                  .setCode(StatusCode.STREAM_NOT_FOUND)
                  .build());
          }
  
          return metaRange.create(streamProps).thenCompose(created -> {
              if (created) {
                  synchronized (streams) {
                      streams.put(streamId, metaRange);
                  }
                  return getActiveRanges(metaRange);
              } else {
                  return FutureUtils.value(GetActiveRangesResponse.newBuilder()
                      .setCode(StatusCode.INTERNAL_SERVER_ERROR)
                      .build());
              }
          });
      }
  
      @Override
      public CompletableFuture<GetActiveRangesResponse> getActiveRanges(GetActiveRangesRequest request) {
          final long streamId = request.getStreamId();
  
          MetaRangeImpl metaRange = streams.get(streamId);
  
          if (null == metaRange) {
              final MetaRangeImpl metaRangeImpl = new MetaRangeImpl(store, executor, rangePlacementPolicy);
              return metaRangeImpl.load(streamId)
                  .thenCompose(mr -> {
                      if (null == mr) {
                          // meta range doesn't exist, talk to root range to get the stream props
                          return clientManager.getStreamProperties(streamId)
                              .thenCompose(streamProperties ->
                                  createStreamIfMissing(streamId, metaRangeImpl, streamProperties));
                      } else {
                          synchronized (streams) {
                              streams.put(streamId, (MetaRangeImpl) mr);
                          }
                          return getActiveRanges(mr);
                      }
                  });
          } else {
              return getActiveRanges(metaRange);
          }
      }
  
      private CompletableFuture<GetActiveRangesResponse> getActiveRanges(MetaRange metaRange) {
          GetActiveRangesResponse.Builder respBuilder = GetActiveRangesResponse.newBuilder();
          return metaRange.getActiveRanges()
              .thenApplyAsync(ranges -> {
                  for (RangeMetadata range : ranges) {
                      RelatedRanges.Builder rrBuilder = RelatedRanges.newBuilder()
                          .setProps(range.getProps())
                          .setType(RelationType.PARENTS)
                          .addAllRelatedRanges(range.getParentsList());
                      respBuilder.addRanges(rrBuilder);
                  }
                  return respBuilder
                      .setCode(StatusCode.SUCCESS)
                      .build();
              }, executor)
              .exceptionally(cause -> respBuilder.setCode(StatusCode.INTERNAL_SERVER_ERROR).build());
      }
  
  }
  