Metrics.java

/*
 * Copyright 2011 Tyler Blair. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without modification, are
 * permitted provided that the following conditions are met:
 *
 *	1. Redistributions of source code must retain the above copyright notice, this list of
 *	   conditions and the following disclaimer.
 *
 *	2. Redistributions in binary form must reproduce the above copyright notice, this list
 *	   of conditions and the following disclaimer in the documentation and/or other materials
 *	   provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ''AS IS'' AND ANY EXPRESS OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
 * FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
 * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * The views and conclusions contained in the software and documentation are those of the
 * authors and contributors and should not be interpreted as representing official policies,
 * either expressed or implied, of anybody else.
 */
package com.bergerkiller.bukkit.common.metrics;

import org.bukkit.Bukkit;
import org.bukkit.configuration.file.YamlConfiguration;
import org.bukkit.configuration.InvalidConfigurationException;
import org.bukkit.plugin.Plugin;
import org.bukkit.plugin.PluginDescriptionFile;

import com.bergerkiller.bukkit.common.ModuleLogger;

import java.io.BufferedReader;
import java.io.File;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.io.UnsupportedEncodingException;
import java.net.Proxy;
import java.net.URL;
import java.net.URLConnection;
import java.net.URLEncoder;
import java.util.ArrayList;
import java.util.Collections;
import java.util.HashSet;
import java.util.Iterator;
import java.util.List;
import java.util.Map.Entry;
import java.util.Set;
import java.util.UUID;
import java.util.logging.Level;
import java.util.logging.Logger;

/**
 * <p> The metrics class obtains data about a plugin and submits statistics about it to the metrics backend. </p> <p>
 * Public methods provided by this class: </p>
 * <code>
 * Graph createGraph(String name); <br/>
 * void addCustomData(BukkitMetrics.Plotter plotter); <br/>
 * void start(); <br/>
 * </code>
 */
public class Metrics {
	/**
	 * The current revision number
	 */
	private final static int REVISION = 6;
	/**
	 * The base url of the metrics domain
	 */
	private static final String BASE_URL = "http://mcstats.org";
	/**
	 * The url used to report a server's status
	 */
	private static final String REPORT_URL = "/report/%s";
	/**
	 * The separator to use for custom data. This MUST NOT change unless you are hosting your own version of metrics and
	 * want to change it.
	 */
	private static final String CUSTOM_DATA_SEPARATOR = "~~";
	/**
	 * Interval of time to ping (in minutes)
	 */
	private static final int PING_INTERVAL = 10;
	/**
	 * Loggers used for logging errors when DEBUG is enabled
	 */
	private static final Logger LOGGER = new ModuleLogger("Metrics");
	/**
	 * The plugin this metrics submits for
	 */
	private final Plugin plugin;
	/**
	 * All of the custom graphs to submit to metrics
	 */
	private final Set<Graph> graphs = Collections.synchronizedSet(new HashSet<Graph>());
	/**
	 * The plugin configuration file
	 */
	private final YamlConfiguration configuration;
	/**
	 * The plugin configuration file
	 */
	private final File configurationFile;
	/**
	 * Unique server id
	 */
	private final String guid;
	/**
	 * Debug mode
	 */
	private final boolean debug;
	/**
	 * Lock for synchronization
	 */
	private final Object optOutLock = new Object();
	/**
	 * The scheduled updating task
	 */
	private Thread updateThread;

	public Metrics(final Plugin plugin) throws IOException {
		if (plugin == null) {
			throw new IllegalArgumentException("Plugin cannot be null");
		}

		this.plugin = plugin;

		// load the config
		configurationFile = getConfigFile();
		configuration = YamlConfiguration.loadConfiguration(configurationFile);

		// add some defaults
		configuration.addDefault("opt-out", false);
		configuration.addDefault("guid", UUID.randomUUID().toString());
		configuration.addDefault("debug", false);

		// Do we need to create the file?
		if (configuration.get("guid", null) == null) {
			configuration.options().header("http://mcstats.org").copyDefaults(true);
			configuration.save(configurationFile);
		}

		// Load the guid then
		guid = configuration.getString("guid");
		debug = configuration.getBoolean("debug", false);
	}

	/**
	 * Removes a previously added Graph
	 * 
	 * @param name of the Graph to remove
	 */
	public void removeGraph(final String name) {
		if (name == null) {
			throw new IllegalArgumentException("Graph name cannot be null");
		}

		synchronized (graphs) {
			graphs.remove(name);
		}
	}

	/**
	 * Construct and create a Graph that can be used to separate specific plotters to their own graphs on the metrics
	 * website. Plotters can be added to the graph object returned.
	 *
	 * @param name The name of the graph
	 * @return Graph object created. Will never return NULL under normal circumstances unless bad parameters are given
	 */
	public Graph createGraph(final String name) {
		if (name == null) {
			throw new IllegalArgumentException("Graph name cannot be null");
		}

		// Construct the graph object
		final Graph graph = new Graph(name);

		// Now we can add our graph
		synchronized (graphs) {
			graphs.add(graph);
		}

		// and return back
		return graph;
	}

	/**
	 * Add a Graph object to BukkitMetrics that represents data for the plugin that should be sent to the backend
	 *
	 * @param graph The name of the graph
	 */
	public void addGraph(final Graph graph) {
		if (graph == null) {
			throw new IllegalArgumentException("Graph cannot be null");
		}

		synchronized (graphs) {
			graphs.add(graph);
		}
	}

	/**
	 * Start measuring statistics. This will immediately create an updating thread, 
	 * immediately sending initial data to the metrics backend, and then after that 
	 * it will post in increments of PING_INTERVAL * 60000 milliseconds.
	 *
	 * @return True if statistics measuring is (now) running, otherwise false.
	 */
	public boolean start() {
		synchronized (optOutLock) {
			// Did we opt out?
			if (isOptOut()) {
				return false;
			}

			// Is metrics already running?
			if (updateThread != null) {
				return true;
			}

			// Set up the updating task (we do not yet start it!)
			updateThread = new Thread("Metrics updating thread of " + plugin.getName()) {
				@Override
				public void run() {
					try {
						boolean firstPost = true;
						final Object syncLock = new Object();
						final List<Graph> graphBuffer = new ArrayList<Graph>();
						while (true) {
							try {
								// Disable Task, if it is running and the server owner decided to opt-out
								if (isOptOut()) {
									// End the updating thread
									return;
								}

								// Update all graphs on the main thread
								graphBuffer.clear();
								synchronized (graphs) {
									graphBuffer.addAll(graphs);
								}
								if (!graphBuffer.isEmpty()) {
									Bukkit.getScheduler().scheduleSyncDelayedTask(plugin, new Runnable() {
										@Override
										public void run() {
											for (Graph graph : graphBuffer) {
												graph.onUpdate(plugin);
											}
											synchronized (syncLock) {
												syncLock.notify();
											}
										}
									});
									// Wait for the previous task to be completed
									synchronized (syncLock) {
										syncLock.wait();
									}
								}

								// We use the inverse of firstPost because if it is the first time we are posting,
								// it is not a interval ping, so it evaluates to FALSE
								// Each time thereafter it will evaluate to TRUE, i.e PING!
								postPlugin(!firstPost);

								// After the first post we set firstPost to false
								// Each post thereafter will be a ping
								firstPost = false;
							} catch (Throwable t) {
								if (debug) {
									LOGGER.log(Level.INFO, t.getMessage());
								}
							}

							// Wait out the pinging interval
							Thread.sleep(60000 * PING_INTERVAL);
						}
					} catch (InterruptedException ex) {
						// Thread is stopped - abort
					}
				}
			};
			updateThread.start();
			return true;
		}
	}

	/**
	 * Stops measuring statistics. This will immediately interrupt the updating
	 * thread, this way disabling all updates to the metrics backend.
	 * 
	 * @return True if the statistics measuring is (now) stopped, otherwise false.
	 */
	public boolean stop() {
		try {
			if (updateThread != null) {
				updateThread.interrupt();
				updateThread = null;
			}
			return true;
		} catch (SecurityException ex) {
			ex.printStackTrace();
			return false;
		}
	}

	/**
	 * Has the server owner denied plugin metrics?
	 *
	 * @return true if metrics should be opted out of it
	 */
	public boolean isOptOut() {
		synchronized (optOutLock) {
			try {
				// Reload the metrics file
				configuration.load(getConfigFile());
			} catch (IOException ex) {
				if (debug) {
					LOGGER.log(Level.INFO, ex.getMessage());
				}
				return true;
			} catch (InvalidConfigurationException ex) {
				if (debug) {
					LOGGER.log(Level.INFO, ex.getMessage());
				}
				return true;
			}
			return configuration.getBoolean("opt-out", false);
		}
	}

	/**
	 * Enables metrics for the server by setting "opt-out" to false in the config file and starting the metrics task.
	 *
	 * @throws java.io.IOException
	 */
	public void enable() throws IOException {
		// This has to be synchronized or it can collide with the check in the task.
		synchronized (optOutLock) {
			// Check if the server owner has already set opt-out, if not, set it.
			if (isOptOut()) {
				configuration.set("opt-out", false);
				configuration.save(configurationFile);
			}
			// Start updating thread
			start();
		}
	}

	/**
	 * Disables metrics for the server by setting "opt-out" to true in the config file and canceling the metrics task.
	 *
	 * @throws java.io.IOException
	 */
	public void disable() throws IOException {
		// This has to be synchronized or it can collide with the check in the task.
		synchronized (optOutLock) {
			// Check if the server owner has already set opt-out, if not, set it.
			if (!isOptOut()) {
				configuration.set("opt-out", true);
				configuration.save(configurationFile);
			}
			// Stop updating thread
			stop();
		}
	}

	/**
	 * Gets the File object of the config file that should be used to store data such as the GUID and opt-out status
	 *
	 * @return the File object for the config file
	 */
	public File getConfigFile() {
		// I believe the easiest way to get the base folder (e.g craftbukkit set via -P) for plugins to use
		// is to abuse the plugin object we already have
		// plugin.getDataFolder() => base/plugins/PluginA/
		// pluginsFolder => base/plugins/
		// The base is not necessarily relative to the startup directory.
		File pluginsFolder = plugin.getDataFolder().getParentFile();

		// return => base/plugins/PluginMetrics/config.yml
		return new File(new File(pluginsFolder, "PluginMetrics"), "config.yml");
	}

	/**
	 * Generic method that posts a plugin to the metrics website
	 */
	private void postPlugin(final boolean isPing) throws IOException {
		// Server software specific section
		PluginDescriptionFile description = plugin.getDescription();
		String pluginName = description.getName();
		boolean onlineMode = Bukkit.getServer().getOnlineMode(); // TRUE if online mode is enabled
		String pluginVersion = description.getVersion();
		String serverVersion = Bukkit.getVersion();
		int playersOnline = Bukkit.getServer().getOnlinePlayers().length;

		// END server software specific section -- all code below does not use any code outside of this class / Java

		// Construct the post data
		final StringBuilder data = new StringBuilder();

		// The plugin's description file containg all of the plugin data such as name, version, author, etc
		data.append(encode("guid")).append('=').append(encode(guid));
		encodeDataPair(data, "version", pluginVersion);
		encodeDataPair(data, "server", serverVersion);
		encodeDataPair(data, "players", Integer.toString(playersOnline));
		encodeDataPair(data, "revision", String.valueOf(REVISION));

		// New data as of R6
		String osname = System.getProperty("os.name");
		String osarch = System.getProperty("os.arch");
		String osversion = System.getProperty("os.version");
		String java_version = System.getProperty("java.version");
		int coreCount = Runtime.getRuntime().availableProcessors();

		// normalize os arch .. amd64 -> x86_64
		if (osarch.equals("amd64")) {
			osarch = "x86_64";
		}

		encodeDataPair(data, "osname", osname);
		encodeDataPair(data, "osarch", osarch);
		encodeDataPair(data, "osversion", osversion);
		encodeDataPair(data, "cores", Integer.toString(coreCount));
		encodeDataPair(data, "online-mode", Boolean.toString(onlineMode));
		encodeDataPair(data, "java_version", java_version);

		// If we're pinging, append it
		if (isPing) {
			encodeDataPair(data, "ping", "true");
		}

		// Acquire a lock on the graphs, which lets us make the assumption we also lock everything
		// inside of the graph (e.g plotters)
		synchronized (graphs) {
			final Iterator<Graph> iter = graphs.iterator();

			while (iter.hasNext()) {
				final Graph graph = iter.next();
				for (Entry<String, Object> entry : graph.getPlotters().entrySet()) {
					// Ignore null values
					if (entry.getValue() == null) {
						continue;
					}
					// The key name to send to the metrics server
					// The format is C-GRAPHNAME-PLOTTERNAME where separator - is defined at the top
					// Legacy (R4) submitters use the format Custom%s, or CustomPLOTTERNAME
					final String key = String.format("C%s%s%s%s", CUSTOM_DATA_SEPARATOR, graph.getName(), CUSTOM_DATA_SEPARATOR, entry.getKey());

					// Add it to the http post data :)
					encodeDataPair(data, key, entry.getValue().toString());
				}
			}
		}

		// Create the url
		URL url = new URL(BASE_URL + String.format(REPORT_URL, encode(pluginName)));

		// Connect to the website
		URLConnection connection;

		// Mineshafter creates a socks proxy, so we can safely bypass it
		// It does not reroute POST requests so we need to go around it
		if (isMineshafterPresent()) {
			connection = url.openConnection(Proxy.NO_PROXY);
		} else {
			connection = url.openConnection();
		}

		connection.setDoOutput(true);

		// Write the data
		final OutputStreamWriter writer = new OutputStreamWriter(connection.getOutputStream());
		writer.write(data.toString());
		writer.flush();

		// Now read the response
		final BufferedReader reader = new BufferedReader(new InputStreamReader(connection.getInputStream()));
		final String response = reader.readLine();

		// close resources
		writer.close();
		reader.close();

		if (response == null || response.startsWith("ERR")) {
			throw new IOException(response); //Throw the exception
		} else {
			// Is this the first update this hour?
			if (response.contains("OK This is your first update this hour")) {
				Bukkit.getScheduler().scheduleSyncDelayedTask(plugin, new Runnable() {
					public void run() {
						synchronized (graphs) {
							for (Graph graph : graphs) {
								graph.onReset(plugin);
							}
						}
					}
				});
			}
		}
	}

	/**
	 * Check if mineshafter is present. If it is, we need to bypass it to send POST requests
	 *
	 * @return true if mineshafter is installed on the server
	 */
	private boolean isMineshafterPresent() {
		try {
			Class.forName("mineshafter.MineServer");
			return true;
		} catch (Exception e) {
			return false;
		}
	}

	/**
	 * <p>Encode a key/value data pair to be used in a HTTP post request. This INCLUDES a & so the first key/value pair
	 * MUST be included manually, e.g:</p>
	 * <code>
	 * StringBuffer data = new StringBuffer();
	 * data.append(encode("guid")).append('=').append(encode(guid));
	 * encodeDataPair(data, "version", description.getVersion());
	 * </code>
	 *
	 * @param buffer the stringbuilder to append the data pair onto
	 * @param key the key value
	 * @param value the value
	 */
	private static void encodeDataPair(final StringBuilder buffer, final String key, final String value) throws UnsupportedEncodingException {
		buffer.append('&').append(encode(key)).append('=').append(encode(value));
	}

	/**
	 * Encode text as UTF-8
	 *
	 * @param text the text to encode
	 * @return the encoded text, as UTF-8
	 */
	private static String encode(final String text) throws UnsupportedEncodingException {
		return URLEncoder.encode(text, "UTF-8");
	}

	/**
	 * Attempts to create new Metrics for the plugin specified, and
	 * starts sending metrics information. If this operation fails,
	 * null is returned.
	 * 
	 * @param plugin to initialize Metrics for
	 * @return the Metrics instance created, or null if this failed
	 */
	public static Metrics initialize(Plugin plugin) {
		try {
			final Metrics m = new Metrics(plugin);
			m.start();
			return m;
		} catch (IOException e) {
			plugin.getLogger().log(Level.SEVERE, "Failed to initialize Metrics");
			e.printStackTrace();
			return null;
		}
	}
}