content: /*
   * The Alluxio Open Foundation licenses this work under the Apache License, version 2.0
   * (the "License"). You may not use this work except in compliance with the License, which is
   * available at www.apache.org/licenses/LICENSE-2.0
   *
   * This software is distributed on an "AS IS" basis, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND,
   * either express or implied, as more fully set forth in the License.
   *
   * See the NOTICE file distributed with this work for information regarding copyright ownership.
   */
  
  package alluxio.metrics.sink;
  
  import alluxio.metrics.MetricsSystem;
  
  import com.codahale.metrics.CsvReporter;
  import com.codahale.metrics.MetricRegistry;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  import java.io.File;
  import java.util.Locale;
  import java.util.Properties;
  import java.util.concurrent.TimeUnit;
  import javax.annotation.concurrent.ThreadSafe;
  
  /**
   * A sink which creates a CSV file of the metric values.
   */
  @ThreadSafe
  public class CsvSink implements Sink {
    private static final Logger LOG = LoggerFactory.getLogger(CsvSink.class);
    private static final int CSV_DEFAULT_PERIOD = 10;
    private static final String CSV_DEFAULT_UNIT = "SECONDS";
    private static final String CSV_DEFAULT_DIR = "/tmp/";
  
    private static final String CSV_KEY_PERIOD = "period";
    private static final String CSV_KEY_UNIT = "unit";
    private static final String CSV_KEY_DIR = "directory";
  
    private CsvReporter mReporter;
    private Properties mProperties;
    private final File mDir;
  
    /**
     * Creates a new {@link CsvSink} with a {@link Properties} and {@link MetricRegistry}.
     *
     * @param properties the properties which may contain polling period, unit and  directory
     *                   properties.
     * @param registry the metric registry to register
     */
    public CsvSink(Properties properties, MetricRegistry registry) {
      mProperties = properties;
      mDir = new File(getPollDir());
      createPollDir(mDir);
      mReporter =
          CsvReporter.forRegistry(registry).formatFor(Locale.US)
              .convertDurationsTo(TimeUnit.MILLISECONDS).convertRatesTo(TimeUnit.SECONDS)
              .build(mDir);
      MetricsSystem.checkMinimalPollingPeriod(getPollUnit(), getPollPeriod());
    }
  
    @Override
    public void start() {
      mReporter.start(getPollPeriod(), getPollUnit());
    }
  
    @Override
    public void stop() {
      mReporter.stop();
    }
  
    @Override
    public void report() {
      mReporter.report();
    }
  
    /**
     * Gets the directory where the CSV files are created.
     *
     * @return the polling directory set by properties. If it is not set, a default value /tmp/ is
     *         returned.
     */
    private String getPollDir() {
      String pollDir = mProperties.getProperty(CSV_KEY_DIR);
      return pollDir != null ? pollDir : CSV_DEFAULT_DIR;
    }
  
    /**
     * Gets the polling period.
     *
     * @return the polling period set by properties. If it is not set, a default value 10 is
     *         returned.
     */
    private int getPollPeriod() {
      String period = mProperties.getProperty(CSV_KEY_PERIOD);
      return period != null ? Integer.parseInt(period) : CSV_DEFAULT_PERIOD;
    }
  
    /**
     * Gets the polling time unit.
     *
     * @return the polling time unit set by properties, If it is not set, a default value SECONDS is
     *         returned.
     */
    private TimeUnit getPollUnit() {
      String unit = mProperties.getProperty(CSV_KEY_UNIT);
      if (unit == null) {
        unit = CSV_DEFAULT_UNIT;
      }
      return TimeUnit.valueOf(unit.toUpperCase());
    }
  
    /**
     * Create the directory for CSV sink if target directory is not created.
     *
     * @param dir CSV target directory
     */
    private void createPollDir(File dir) {
      if (!dir.exists()) {
        try {
          dir.mkdirs();
        } catch (SecurityException e) {
          LOG.warn("Fail to create directory {} for CSV sink, {}", dir, e.toString());
        }
      }
    }
  }
  