/**
    * 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.chukwa.inputtools.log4j;
  
  import org.json.simple.JSONObject;
  import org.apache.log4j.Logger;
  import org.apache.log4j.PatternLayout;
  import org.apache.commons.configuration.SubsetConfiguration;
  import org.apache.hadoop.metrics2.Metric;
  import org.apache.hadoop.metrics2.MetricsRecord;
  import org.apache.hadoop.metrics2.MetricsSink;
  import org.apache.hadoop.metrics2.MetricsTag;
  
  public class Log4jMetricsSink implements MetricsSink {
    /* Configuration attribute names */
    private static final String HOST_PROPERTY = "host";
    private static final String PORT_PROPERTY = "port";
    private static final String TIMESTAMP = "timestamp";
    private static String CONTEXT = "context";
    private static final String CONTEXT_NAME = "contextName";
    private static final String RECORD_NAME = "recordName";
    protected String context = "HadoopMetrics";
    protected String host = "localhost";
    protected int port = 9095;
    protected Logger out = null;
  
    @Override
    public void init(SubsetConfiguration conf) {
      String host = conf.getString(HOST_PROPERTY);
      if (host != null) {
        this.host = host;
      }
      String port = conf.getString(PORT_PROPERTY);
      if (port != null) {
        this.port = Integer.parseInt(port);
      }
      String context = conf.getString(CONTEXT);
      if (context != null) {
        this.context = context;
      }
  
      PatternLayout layout = new PatternLayout("%d{ISO8601} %p %c: %m%n");
  
      org.apache.log4j.net.SocketAppender appender = new org.apache.log4j.net.SocketAppender(this.host, this.port);
  
      appender.setName("chukwa.metrics." + this.context);
      appender.setLayout(layout);
  
      Logger logger = Logger.getLogger("chukwa.metrics." + this.context);
      logger.setAdditivity(false);
      logger.addAppender(appender);
      appender.activateOptions();
      out = logger;
    }
    
    @Override
    @SuppressWarnings("unchecked")
    public void putMetrics(MetricsRecord record) {
        JSONObject json = new JSONObject();
        json.put(TIMESTAMP, Long.valueOf(record.timestamp()));
        json.put(CONTEXT_NAME, record.context());
        json.put(RECORD_NAME, record.name());
        for (MetricsTag tag : record.tags()) {
          json.put(tag.name(), tag.value());
        }
        for (Metric metric : record.metrics()) {
          json.put(metric.name(), metric.value());
        }
        out.info(json);
    }
  
    @Override
    public void flush() {
    }
  }