/**
* Licensed to Cloudera, Inc. under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. Cloudera, Inc. 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 com.cloudera.flume.handlers.avro;
import java.io.IOException;
import java.io.OutputStream;
import org.apache.avro.Schema;
import org.apache.avro.io.JsonEncoder;
import org.apache.avro.reflect.ReflectData;
import org.apache.avro.reflect.ReflectDatumWriter;
import com.cloudera.flume.core.Event;
import com.cloudera.flume.core.EventImpl;
import com.cloudera.flume.handlers.text.FormatFactory.OutputFormatBuilder;
import com.cloudera.flume.handlers.text.output.AbstractOutputFormat;
import com.cloudera.flume.handlers.text.output.OutputFormat;
import com.google.common.base.Preconditions;
/**
* This uses the Avro's Reflection serializer to output Flume events as json.
* Instead of using DataFileWriter we just write to a file and break records up
* with a '\n'.
*
* This is not thread safe.
*/
public class AvroJsonOutputFormat extends AbstractOutputFormat {
final static ReflectData reflectData = ReflectData.get();
final static Schema schema = reflectData.getSchema(EventImpl.class);
private static final String NAME = "avrojson";
ReflectDatumWriter<EventImpl> writer = new ReflectDatumWriter<EventImpl>(
schema);
OutputStream cachedOut = null;
JsonEncoder json = null;
public AvroJsonOutputFormat() {
}
@Override
public void format(OutputStream o, Event e) throws IOException {
if (json == null) {
// first time, no current OutputStream
json = new JsonEncoder(schema, o);
cachedOut = o;
}
if (cachedOut != o) {
// different output than last time?
json.init(o);
cachedOut = o;
}
EventImpl ei = null;
if (e instanceof EventImpl) {
ei = (EventImpl) e;
} else {
// copy constructor to force into an EventImpl for reflection
ei = new EventImpl(e);
}
writer.write(ei, json);
json.flush();
o.write('\n');
}
public static OutputFormatBuilder builder() {
return new OutputFormatBuilder() {
@Override
public OutputFormat build(String... args) {
Preconditions.checkArgument(args.length == 0, "usage: avrojson");
OutputFormat format = new AvroJsonOutputFormat();
format.setBuilder(this);
return format;
}
@Override
public String getName() {
return NAME;
}
};
}
}