com.heroku.agent.metrics.Reporter Maven / Gradle / Ivy

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This artifact is for use with the JVM Runtime Metrics features. It is a lightweight Java agent that uses a Prometheus Java client to report metrics.

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package com.heroku.agent.metrics;

import javax.net.ssl.HttpsURLConnection;
import java.io.BufferedReader;
import java.io.DataOutputStream;
import java.io.IOException;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.concurrent.locks.LockSupport;

/**
 * @author Joe Kutner on 11/2/17.
 *         Twitter: @codefinger
 */
public class Reporter {

  private URL url;

  private static final Integer MAX_RETRIES = 3;

  public Reporter() throws MalformedURLException {
    String urlString = System.getenv("HEROKU_METRICS_URL");
    if (urlString != null) {
      this.url = new URL(urlString);
    }
  }

  public Boolean enabled() {
    return this.url != null;
  }

  public void report(String message) throws IOException {
    if (enabled()) {
      sendPost(message);
    }
  }

  private Boolean sendPost(String message) throws IOException {
    return sendPost(message, 0);
  }

  private Boolean sendPost(String message, Integer retries) throws IOException {
    HttpURLConnection con = (HttpURLConnection) url.openConnection();

    con.setRequestMethod("POST");

    String now = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ssXXX").format(new Date());

    con.setRequestProperty("Content-Type", "application/json");
    con.setRequestProperty("Measurements-Count", "1");
    con.setRequestProperty("Measurements-Time", now);

    con.setDoOutput(true);
    DataOutputStream wr = new DataOutputStream(con.getOutputStream());

    wr.writeBytes(message);
    wr.flush();
    wr.close();

    int responseCode = con.getResponseCode();

    if (responseCode >= 400 && responseCode < 500) {
      BufferedReader in = new BufferedReader(new InputStreamReader(con.getInputStream()));
      String inputLine;
      StringBuilder response = new StringBuilder();
      while ((inputLine = in.readLine()) != null) {
        response.append(inputLine);
      }
      in.close();

      System.out.println("error at=send-post component=heroku-java-metrics-agent message=\"upstream service error\" status=" + responseCode + " response=\"" + response + "\"");
      return false;
    } else if (responseCode >= 200 && responseCode < 300) {
      return true;
    } else {
      if (retries > MAX_RETRIES) {
        return false;
      } else {
        LockSupport.parkNanos(2 * 1000000);
        return sendPost(message, retries + 1);
      }
    }
  }
}