/**
* 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.hadoop.metrics2.sink;
import java.io.Closeable;
import java.io.File;
import java.io.FileWriter;
import java.io.IOException;
import java.io.PrintWriter;
import org.apache.commons.configuration.SubsetConfiguration;
import org.apache.hadoop.classification.InterfaceAudience;
import org.apache.hadoop.classification.InterfaceStability;
import org.apache.hadoop.metrics2.AbstractMetric;
import org.apache.hadoop.metrics2.MetricsException;
import org.apache.hadoop.metrics2.MetricsRecord;
import org.apache.hadoop.metrics2.MetricsSink;
import org.apache.hadoop.metrics2.MetricsTag;
/**
* A metrics sink that writes to a file
*/
@InterfaceAudience.Public
@InterfaceStability.Evolving
public class FileSink implements MetricsSink, Closeable {
private static final String FILENAME_KEY = "filename";
private PrintWriter writer;
@Override
public void init(SubsetConfiguration conf) {
String filename = conf.getString(FILENAME_KEY);
try {
writer = filename == null
? new PrintWriter(System.out)
: new PrintWriter(new FileWriter(new File(filename), true));
}
catch (Exception e) {
throw new MetricsException("Error creating "+ filename, e);
}
}
@Override
public void putMetrics(MetricsRecord record) {
writer.print(record.timestamp());
writer.print(" ");
writer.print(record.context());
writer.print(".");
writer.print(record.name());
String separator = ": ";
for (MetricsTag tag : record.tags()) {
writer.print(separator);
separator = ", ";
writer.print(tag.name());
writer.print("=");
writer.print(tag.value());
}
for (AbstractMetric metric : record.metrics()) {
writer.print(separator);
separator = ", ";
writer.print(metric.name());
writer.print("=");
writer.print(metric.value());
}
writer.println();
}
@Override
public void flush() {
writer.flush();
}
@Override
public void close() throws IOException {
writer.close();
}
}