| /* |
| * 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 |
| * |
| * https://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.trevni.avro.mapreduce; |
| |
| import java.io.IOException; |
| import java.io.OutputStream; |
| import java.nio.charset.StandardCharsets; |
| import java.util.Map.Entry; |
| |
| import org.apache.avro.Schema; |
| import org.apache.avro.reflect.ReflectData; |
| import org.apache.hadoop.conf.Configuration; |
| import org.apache.hadoop.fs.FileSystem; |
| import org.apache.hadoop.fs.Path; |
| import org.apache.hadoop.mapreduce.RecordWriter; |
| import org.apache.hadoop.mapreduce.TaskAttemptContext; |
| import org.apache.hadoop.mapreduce.lib.output.FileOutputFormat; |
| import org.apache.trevni.ColumnFileMetaData; |
| import org.apache.trevni.avro.AvroColumnWriter; |
| |
| /** |
| * Abstract base class for <code>RecordWriter</code>s that writes Trevni |
| * container files. |
| * |
| * @param <K> The type of key the record writer should generate. |
| * @param <V> The type of value the record wrtier should generate. |
| * @param <T> The type of the entries within the Trevni container file being |
| * written. |
| */ |
| public abstract class AvroTrevniRecordWriterBase<K, V, T> extends RecordWriter<K, V> { |
| |
| /** trevni file extension */ |
| public final static String EXT = ".trv"; |
| |
| /** prefix of job configs that we care about */ |
| public static final String META_PREFIX = "trevni.meta."; |
| |
| /** |
| * Counter that increments as new trevni files are create because the current |
| * file has exceeded the block size |
| */ |
| protected int part = 0; |
| |
| /** Trevni file writer */ |
| protected AvroColumnWriter<T> writer; |
| |
| /** This will be a unique directory linked to the task */ |
| final Path dirPath; |
| |
| /** HDFS object */ |
| final FileSystem fs; |
| |
| /** Current configured blocksize */ |
| final long blockSize; |
| |
| /** Provided avro schema from the context */ |
| protected Schema schema; |
| |
| /** meta data to be stored in the output file. */ |
| protected ColumnFileMetaData meta; |
| |
| /** |
| * Constructor. |
| * |
| * @param context The TaskAttempContext to supply the writer with information |
| * form the job configuration |
| */ |
| public AvroTrevniRecordWriterBase(TaskAttemptContext context) throws IOException { |
| |
| schema = initSchema(context); |
| meta = filterMetadata(context.getConfiguration()); |
| writer = new AvroColumnWriter<>(schema, meta, ReflectData.get()); |
| |
| Path outputPath = FileOutputFormat.getOutputPath(context); |
| |
| String dir = FileOutputFormat.getUniqueFile(context, "part", ""); |
| dirPath = new Path(outputPath.toString() + "/" + dir); |
| fs = dirPath.getFileSystem(context.getConfiguration()); |
| fs.mkdirs(dirPath); |
| |
| blockSize = fs.getDefaultBlockSize(dirPath); |
| } |
| |
| /** |
| * Use the task context to construct a schema for writing |
| * |
| * @throws IOException |
| */ |
| abstract protected Schema initSchema(TaskAttemptContext context); |
| |
| /** |
| * A Trevni flush will close the current file and prep a new writer |
| * |
| * @throws IOException |
| */ |
| public void flush() throws IOException { |
| try (OutputStream out = fs.create(new Path(dirPath, "part-" + (part++) + EXT))) { |
| writer.writeTo(out); |
| } |
| writer = new AvroColumnWriter<>(schema, meta, ReflectData.get()); |
| } |
| |
| /** {@inheritDoc} */ |
| @Override |
| public void close(TaskAttemptContext arg0) throws IOException, InterruptedException { |
| flush(); |
| } |
| |
| static ColumnFileMetaData filterMetadata(final Configuration configuration) { |
| final ColumnFileMetaData meta = new ColumnFileMetaData(); |
| |
| for (Entry<String, String> confEntry : configuration) { |
| if (confEntry.getKey().startsWith(META_PREFIX)) |
| meta.put(confEntry.getKey().substring(META_PREFIX.length()), |
| confEntry.getValue().getBytes(StandardCharsets.UTF_8)); |
| } |
| |
| return meta; |
| } |
| } |