StatsdClient.java

/*
 * Seldon -- open source prediction engine
 * =======================================
 *
 * Copyright 2011-2015 Seldon Technologies Ltd and Rummble Ltd (http://www.seldon.io/)
 *
 * ********************************************************************************************
 *
 * Licensed 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 io.seldon.api.statsd;

/**
 * StatsdClient.java
 *
 * (C) 2011 Meetup, Inc.
 * Author: Andrew Gwozdziewycz <andrew@meetup.com>, @apgwoz
 *
 *
 *
 * Example usage:
 *
 *    StatsdClient client = new StatsdClient("statsd.example.com", 8125);
 *    // increment by 1
 *    client.increment("foo.bar.baz");
 *    // increment by 10
 *    client.increment("foo.bar.baz", 10);
 *    // sample rate
 *    client.increment("foo.bar.baz", 10, .1);
 *    // increment multiple keys by 1
 *    client.increment("foo.bar.baz", "foo.bar.boo", "foo.baz.bar");
 *    // increment multiple keys by 10 -- yeah, it's "backwards"
 *    client.increment(10, "foo.bar.baz", "foo.bar.boo", "foo.baz.bar");
 *    // multiple keys with a sample rate
 *    client.increment(10, .1, "foo.bar.baz", "foo.bar.boo", "foo.baz.bar");
 *
 * Note: For best results, and greater availability, you'll probably want to
 * create a wrapper class which creates a static client and proxies to it.
 *
 * You know... the "Java way."
 */

import java.io.IOException;
import java.net.InetAddress;
import java.net.InetSocketAddress;
import java.net.UnknownHostException;
import java.nio.ByteBuffer;
import java.nio.channels.DatagramChannel;
import java.util.Locale;
import java.util.Random;

import org.apache.log4j.Logger;

public class StatsdClient {
	//private static final Random RNG = new Random();
	
	private static final ThreadLocal<Random> safeRNG = new ThreadLocal<Random>() {
	    @Override protected Random initialValue() {
	        return new Random();
	    }
	};
	
	private static final Logger log = Logger.getLogger(StatsdClient.class.getName());

	private final InetSocketAddress _address;
	private final DatagramChannel _channel;

	public StatsdClient(String host, int port) throws UnknownHostException, IOException {
		this(InetAddress.getByName(host), port);
	}

	public StatsdClient(InetAddress host, int port) throws IOException {
		_address = new InetSocketAddress(host, port);
		_channel = DatagramChannel.open();
	}

	public boolean timing(String key, int value) {
		return timing(key, value, 1.0);
	}

	public boolean timing(String key, int value, double sampleRate) {
		return send(sampleRate, String.format(Locale.ENGLISH, "%s:%d|ms", key, value));
	}

	public boolean decrement(String key) {
		return increment(key, -1, 1.0);
	}

	public boolean decrement(String key, int magnitude) {
		return decrement(key, magnitude, 1.0);
	}

	public boolean decrement(String key, int magnitude, double sampleRate) {
		magnitude = magnitude < 0 ? magnitude : -magnitude;
		return increment(key, magnitude, sampleRate);
	}

	public boolean decrement(String... keys) {
		return increment(-1, 1.0, keys);
	}

	public boolean decrement(int magnitude, String... keys) {
		magnitude = magnitude < 0 ? magnitude : -magnitude;
		return increment(magnitude, 1.0, keys);
	}

	public boolean decrement(int magnitude, double sampleRate, String... keys) {
		magnitude = magnitude < 0 ? magnitude : -magnitude;
		return increment(magnitude, sampleRate, keys);
	}

	public boolean increment(String key) {
		return increment(key, 1, 1.0);
	}

	public boolean increment(String key, int magnitude) {
		return increment(key, magnitude, 1.0);
	}

	public boolean increment(String key, int magnitude, double sampleRate) {
		String stat = String.format(Locale.ENGLISH, "%s:%s|c", key, magnitude);
		return send(sampleRate, stat);
	}

	public boolean increment(int magnitude, double sampleRate, String... keys) {
		String[] stats = new String[keys.length];
		for (int i = 0; i < keys.length; i++) {
			stats[i] = String.format(Locale.ENGLISH, "%s:%s|c", keys[i], magnitude);
		}
		return send(sampleRate, stats);
	}

	public boolean gauge(String key, double magnitude){
		return gauge(key, magnitude, 1.0);
	}

	public boolean gauge(String key, double magnitude, double sampleRate){
		final String stat = String.format(Locale.ENGLISH, "%s:%s|g", key, magnitude);
		return send(sampleRate, stat);
	}

	private boolean send(double sampleRate, String... stats) {

		boolean retval = false; // didn't send anything
		if (sampleRate < 1.0) {
			for (String stat : stats) {
				if (safeRNG.get().nextDouble() <= sampleRate) {
					stat = String.format(Locale.ENGLISH, "%s|@%f", stat, sampleRate);
					if (doSend(stat)) {
						retval = true;
					}
				}
			}
		} else {
			for (String stat : stats) {
				if (doSend(stat)) {
					retval = true;
				}
			}
		}

		return retval;
	}

	private boolean doSend(final String stat) {
		try {
			final byte[] data = stat.getBytes("utf-8");
			final ByteBuffer buff = ByteBuffer.wrap(data);
			final int nbSentBytes = _channel.send(buff, _address);

			if (data.length == nbSentBytes) {
				return true;
			} else {
				log.error(String.format(
						"Could not send entirely stat %s to host %s:%d. Only sent %d bytes out of %d bytes", stat,
						_address.getHostName(), _address.getPort(), nbSentBytes, data.length));
				return false;
			}

		} catch (IOException e) {
			log.error(
					String.format("Could not send stat %s to host %s:%d", stat, _address.getHostName(),
							_address.getPort()), e);
			return false;
		}
	}
}