001 /**
002 * Licensed to the Apache Software Foundation (ASF) under one
003 * or more contributor license agreements. See the NOTICE file
004 * distributed with this work for additional information
005 * regarding copyright ownership. The ASF licenses this file
006 * to you under the Apache License, Version 2.0 (the
007 * "License"); you may not use this file except in compliance
008 * with the License. You may obtain a copy of the License at
009 *
010 * http://www.apache.org/licenses/LICENSE-2.0
011 *
012 * Unless required by applicable law or agreed to in writing, software
013 * distributed under the License is distributed on an "AS IS" BASIS,
014 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
015 * See the License for the specific language governing permissions and
016 * limitations under the License.
017 */
018
019 package org.apache.hadoop.metrics2.sink;
020
021 import java.io.BufferedOutputStream;
022 import java.io.File;
023 import java.io.FileWriter;
024 import java.io.PrintWriter;
025
026 import org.apache.commons.configuration.SubsetConfiguration;
027 import org.apache.hadoop.classification.InterfaceAudience;
028 import org.apache.hadoop.classification.InterfaceStability;
029 import org.apache.hadoop.metrics2.AbstractMetric;
030 import org.apache.hadoop.metrics2.MetricsException;
031 import org.apache.hadoop.metrics2.MetricsRecord;
032 import org.apache.hadoop.metrics2.MetricsSink;
033 import org.apache.hadoop.metrics2.MetricsTag;
034
035 /**
036 * A metrics sink that writes to a file
037 */
038 @InterfaceAudience.Public
039 @InterfaceStability.Evolving
040 public class FileSink implements MetricsSink {
041 private static final String FILENAME_KEY = "filename";
042 private PrintWriter writer;
043
044 @Override
045 public void init(SubsetConfiguration conf) {
046 String filename = conf.getString(FILENAME_KEY);
047 try {
048 writer = filename == null
049 ? new PrintWriter(System.out)
050 : new PrintWriter(new FileWriter(new File(filename), true));
051 }
052 catch (Exception e) {
053 throw new MetricsException("Error creating "+ filename, e);
054 }
055 }
056
057 @Override
058 public void putMetrics(MetricsRecord record) {
059 writer.print(record.timestamp());
060 writer.print(" ");
061 writer.print(record.context());
062 writer.print(".");
063 writer.print(record.name());
064 String separator = ": ";
065 for (MetricsTag tag : record.tags()) {
066 writer.print(separator);
067 separator = ", ";
068 writer.print(tag.name());
069 writer.print("=");
070 writer.print(tag.value());
071 }
072 for (AbstractMetric metric : record.metrics()) {
073 writer.print(separator);
074 separator = ", ";
075 writer.print(metric.name());
076 writer.print("=");
077 writer.print(metric.value());
078 }
079 writer.println();
080 }
081
082 @Override
083 public void flush() {
084 writer.flush();
085 }
086 }