johnyangk commented on a change in pull request #219: [NEMO-351] Empowering Nemo with fast I/O using Apache Crail URL: https://github.com/apache/incubator-nemo/pull/219#discussion_r292262441
########## File path: runtime/executor/src/main/java/org/apache/nemo/runtime/executor/data/stores/CrailFileStore.java ########## @@ -0,0 +1,174 @@ +/* + * 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.nemo.runtime.executor.data.stores; + +import org.apache.crail.*; +import org.apache.crail.conf.CrailConfiguration; +import org.apache.nemo.common.exception.BlockFetchException; +import org.apache.nemo.conf.JobConf; +import org.apache.nemo.common.exception.BlockWriteException; +import org.apache.nemo.runtime.executor.data.*; +import org.apache.nemo.runtime.executor.data.block.Block; +import org.apache.nemo.runtime.executor.data.block.CrailFileBlock; +import org.apache.nemo.runtime.executor.data.metadata.CrailFileMetadata; +import org.apache.nemo.runtime.executor.data.streamchainer.Serializer; +import org.apache.reef.tang.annotations.Parameter; + +import javax.annotation.concurrent.ThreadSafe; +import javax.inject.Inject; +import java.io.IOException; +import java.io.Serializable; +import java.util.Optional; + +/** + * Stores blocks in CrailStore. + * Since the data is stored in CrailStore and globally accessed by multiple nodes, + * each read, or deletion for a file needs one instance of {@link CrailFileBlock}. + * When CrailFileBlock is created, it's metadata is maintained in memory until the block is committed. + * After the block is committed, the metadata is stored in and read from a CrailStore. + */ +@ThreadSafe +public final class CrailFileStore extends AbstractBlockStore implements RemoteFileStore { + private final String fileDirectory; + private CrailConfiguration conf; + private CrailStore fs; + + /** + * Constructor. + * + * @param volumeDirectory the CrailStore directory where we contain the files. + * @param jobId the job id. + * @param serializerManager the serializer manager. + * @throws Exception for any error occurred while trying to set Crail requirements. + */ + @Inject + private CrailFileStore(@Parameter(JobConf.CrailVolumeDirectory.class) final String volumeDirectory, + @Parameter(JobConf.JobId.class) final String jobId, + final SerializerManager serializerManager) throws Exception { + super(serializerManager); + this.conf = CrailConfiguration.createConfigurationFromFile(); + this.fs = CrailStore.newInstance(conf); + this.fileDirectory = volumeDirectory; + } + + @Override + public Block createBlock(final String blockId) { + deleteBlock(blockId); + final Serializer serializer = getSerializerFromWorker(blockId); + final String filePath = DataUtil.blockIdToFilePath(blockId, fileDirectory); + final String metaPath = DataUtil.blockIdToMetaFilePath(blockId, fileDirectory); + final CrailFileMetadata metadata = CrailFileMetadata.create(metaPath, fs); + return new CrailFileBlock<>(blockId, serializer, filePath, metadata, fs); + } + + /** + * Writes a committed block to this store. + * + * @param block the block to write. + * @throws BlockWriteException if fail to write. + */ + + @Override + public void writeBlock(final Block block) throws BlockWriteException { + if (!(block instanceof CrailFileBlock)) { + throw new BlockWriteException(new Throwable( + this.toString() + " only accept " + CrailFileBlock.class.getName())); + } else if (!block.isCommitted()) { + throw new BlockWriteException(new Throwable("The block " + block.getId() + "is not committed yet.")); + } + // Do nothing. The block have to be written in CrailStore file during commit. + } + + /** + * Reads a committed block from this store. + * + * @param blockId of the target partition. + * @return the target block (if it exists). + * @throws BlockFetchException for any error occurred while trying to fetch a block. + */ + + @Override + + public Optional<Block> readBlock(final String blockId) throws BlockFetchException { + final String filePath = DataUtil.blockIdToFilePath(blockId, fileDirectory); + try { + if (fs.lookup(filePath).get() == null) { + return Optional.empty(); + } else { + try { + final CrailFileBlock block = getBlockFromFile(blockId); + return Optional.of(block); + } catch (final IOException e) { + throw new BlockFetchException(e); + } catch (Exception e) { Review comment: Please use a more specific Exception class. ---------------------------------------------------------------- This is an automated message from the Apache Git Service. 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