/**
* Copyright 2014 IPONWEB
*
* Licensed 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 net.iponweb.hadoop.streaming.avro;
import org.apache.avro.Schema;
import org.apache.avro.file.CodecFactory;
import org.apache.avro.file.DataFileWriter;
import org.apache.avro.generic.GenericDatumReader;
import org.apache.avro.generic.GenericDatumWriter;
import org.apache.avro.generic.GenericRecord;
import org.apache.avro.io.DatumReader;
import org.apache.avro.io.Decoder;
import org.apache.avro.mapred.AvroJob;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.io.NullWritable;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.mapred.FileOutputFormat;
import org.apache.hadoop.mapred.JobConf;
import org.apache.hadoop.mapred.RecordWriter;
import org.apache.hadoop.mapred.Reporter;
import org.apache.hadoop.util.Progressable;
import java.io.File;
import java.io.IOException;
import java.io.UnsupportedEncodingException;
import java.net.URLDecoder;
import java.util.Map;
import static org.apache.avro.file.DataFileConstants.DEFAULT_SYNC_INTERVAL;
import static org.apache.avro.file.DataFileConstants.DEFLATE_CODEC;
/**
* Output format for streaming jobs converting JSON representation into Avro record
* Multiple output schemas supported in combination with ByKeyOutputFormat. To use
* this feature one must set configuration option
* 'iow.streaming.schema.use.prefix' to true, provide output
* schemas as files to the job and name them in the first column of output in following
* format: 'filename:schema' where filename is name of file, where current record should
* be placed and 'schema' is name of file containing output schema
*
* For single type of output schema, it should be set in parameter
* 'iow.streaming.output.schema' which defaults to 'streaming_output_schema'
*
*
*/
public class AvroAsJsonOutputFormat extends FileOutputFormat<Text, NullWritable> {
protected static Log LOG = LogFactory.getLog(AvroAsJsonOutputFormat.class);
static <K> void configureDataFileWriter(DataFileWriter<K> writer,
JobConf job) throws UnsupportedEncodingException {
if (FileOutputFormat.getCompressOutput(job)) {
int level = job.getInt(org.apache.avro.mapred.AvroOutputFormat.DEFLATE_LEVEL_KEY,
org.apache.avro.mapred.AvroOutputFormat.DEFAULT_DEFLATE_LEVEL);
String codecName = job.get(AvroJob.OUTPUT_CODEC, DEFLATE_CODEC);
CodecFactory factory = codecName.equals(DEFLATE_CODEC) ?
CodecFactory.deflateCodec(level) : CodecFactory.fromString(codecName);
writer.setCodec(factory);
}
writer.setSyncInterval(job.getInt(org.apache.avro.mapred.AvroOutputFormat.SYNC_INTERVAL_KEY,
DEFAULT_SYNC_INTERVAL));
// copy metadata from job
for (Map.Entry<String,String> e : job) {
if (e.getKey().startsWith(AvroJob.TEXT_PREFIX))
writer.setMeta(e.getKey().substring(AvroJob.TEXT_PREFIX.length()),e.getValue());
if (e.getKey().startsWith(AvroJob.BINARY_PREFIX))
writer.setMeta(e.getKey().substring(AvroJob.BINARY_PREFIX.length()),
URLDecoder.decode(e.getValue(), "ISO-8859-1")
.getBytes("ISO-8859-1"));
}
}
@Override
public RecordWriter<Text, NullWritable>
getRecordWriter(FileSystem ignore, JobConf job, String name, Progressable prog)
throws IOException {
Schema schema;
Schema.Parser p = new Schema.Parser();
String strSchema = job.get("iow.streaming.output.schema");
if (strSchema == null) {
String schemaFile = job.get("iow.streaming.output.schema.file", "streaming_output_schema");
if (job.getBoolean("iow.streaming.schema.use.prefix", false)) {
// guess schema from file name
// format is: schema:filename
// with special keyword default - 'default:filename'
String str[] = name.split(":");
if (!str[0].equals("default"))
schemaFile = str[0];
name = str[1];
}
LOG.info(this.getClass().getSimpleName() + ": Using schema from file: " + schemaFile);
File f = new File(schemaFile);
schema = p.parse(f);
}
else {
LOG.info(this.getClass().getSimpleName() + ": Using schema from jobconf.");
schema = p.parse(strSchema);
}
if (schema == null) {
throw new IOException("Can't find proper output schema");
}
DataFileWriter<GenericRecord> writer = new DataFileWriter<GenericRecord>(new GenericDatumWriter<GenericRecord>());
configureDataFileWriter(writer, job);
Path path = FileOutputFormat.getTaskOutputPath(job, name + org.apache.avro.mapred.AvroOutputFormat.EXT);
writer.create(schema, path.getFileSystem(job).create(path));
return createRecordWriter(writer, schema);
}
protected RecordWriter<Text, NullWritable> createRecordWriter(final DataFileWriter<GenericRecord> w, final Schema schema) {
return new AvroAsJsonRecordWriter(w, schema);
}
protected class AvroAsJsonRecordWriter implements RecordWriter<Text, NullWritable> {
private final DataFileWriter<GenericRecord> writer;
private final Schema schema;
public AvroAsJsonRecordWriter(DataFileWriter<GenericRecord> writer, Schema schema) {
this.writer = writer;
this.schema = schema;
}
@Override
public void write(Text k, NullWritable v) throws IOException {
writer.append(fromJson(k.toString(), schema));
}
@Override
public void close(Reporter reporter) throws IOException {
writer.close();
}
protected GenericRecord fromJson(String txt, Schema schema) throws IOException {
DatumReader<GenericRecord> reader = new GenericDatumReader<GenericRecord>(schema);
Decoder decoder = new IOWJsonDecoder(schema, txt);
return reader.read(null, decoder);
}
}
}
