GraphiteContext.java

/*
 * GangliaContext.java
 *
 * 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.metrics.graphite;

import java.io.BufferedOutputStream;
import java.io.IOException;
import java.io.OutputStreamWriter;
import java.io.Writer;

import org.apache.hadoop.metrics.ContextFactory;
import org.apache.hadoop.metrics.spi.AbstractMetricsContext;
import org.apache.hadoop.metrics.spi.OutputRecord;

import java.net.Socket;
import java.net.SocketException;

/**
 * Metrics context for writing metrics to Graphite.<p/>
 *
 * This class is configured by setting ContextFactory attributes which in turn
 * are usually configured through a properties file.  All the attributes are
 * prefixed by the contextName. For example, the properties file might contain:
 * <pre>
 * mapred.class=org.apache.hadoop.metrics.graphite.GraphiteContext
 * mapred.period=60
 * mapred.serverName=graphite.foo.bar
 * mapred.port=2013
 * </pre>
 */
public class GraphiteContext extends AbstractMetricsContext {
    
  /* Configuration attribute names */
  protected static final String SERVER_NAME_PROPERTY = "serverName";
  protected static final String PERIOD_PROPERTY = "period";
  protected static final String PORT = "port";
  protected static final String PATH = "path";
  private String serverName = null;
  private String pathName = null;
  private int port = 0; 
    
  /** Creates a new instance of GraphiteContext */
  public GraphiteContext() {}
    
  public void init(String contextName, ContextFactory factory) {
    super.init(contextName, factory);

    serverName = getAttribute(SERVER_NAME_PROPERTY);
    port = Integer.parseInt(getAttribute(PORT));

    pathName = getAttribute(PATH);
    if (pathName == null) {
        pathName = "Platform.Hadoop";
    }
        
    parseAndSetPeriod(PERIOD_PROPERTY);

  }

  /**
   * Emits a metrics record to Graphite.
   */
  public void emitRecord(String contextName, String recordName, OutputRecord outRec) throws IOException {
    StringBuilder sb = new StringBuilder();
    String hostname = outRec.getTag("hostName").toString(); // Only want to send first part of hostname.  
    String split[] = hostname.split("[.]");
    String metric = pathName + "." + contextName + "." + split[0] + "."; // Need to make the first part configurable
    long tm = System.currentTimeMillis() / 1000; // Graphite doesn't handle milliseconds
    for (String metricName : outRec.getMetricNames()) {
        sb.append(metric);
        sb.append(metricName);
        String separator = " ";
        sb.append(separator);
        sb.append(outRec.getMetric(metricName));
        sb.append(separator);
        sb.append(tm);
        sb.append("\n");
        emitMetric(sb.toString()); 
        sb = null; 
        sb = new StringBuilder();
    }
  }

  protected void emitMetric(String metric) throws IOException {
      Socket socket = new Socket(serverName, port);
      try { 
          Writer writer = new OutputStreamWriter(socket.getOutputStream());
          writer.write(metric);
          writer.flush();
          writer.close();
      } finally { 
          socket.close();
      }
  }
}