Java tutorial
/** * Global Sensor Networks (GSN) Source Code * Copyright (c) 2006-2014, Ecole Polytechnique Federale de Lausanne (EPFL) * * This file is part of GSN. * * GSN is free software: you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation, either version 3 of the License, or * (at your option) any later version. * * GSN is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with GSN. If not, see <http://www.gnu.org/licenses/>. * * File: src/gsn/utils/VSMonitor.java * * @author Sofiane Sarni * @author Ali Salehi * */ package gsn.utils; import gsn.beans.GSNSessionAddress; import gsn.beans.VSensorMonitorConfig; import java.io.BufferedReader; import java.io.FileReader; import java.io.IOException; import java.io.PrintWriter; import java.io.StringReader; import java.io.StringWriter; import java.net.ConnectException; import java.net.UnknownHostException; import java.text.ParseException; import java.util.GregorianCalendar; import java.util.HashMap; import java.util.Iterator; import java.util.List; import java.util.Vector; import javax.xml.parsers.DocumentBuilder; import javax.xml.parsers.DocumentBuilderFactory; import org.apache.commons.mail.EmailException; import org.apache.commons.mail.SimpleEmail; import org.apache.http.auth.AuthScope; import org.apache.http.auth.UsernamePasswordCredentials; import org.apache.http.client.HttpResponseException; import org.apache.http.client.ResponseHandler; import org.apache.http.client.methods.HttpGet; import org.apache.http.impl.client.BasicResponseHandler; import org.apache.http.impl.client.DefaultHttpClient; import org.slf4j.LoggerFactory; import org.slf4j.Logger; import org.w3c.dom.Document; import org.w3c.dom.Element; import org.w3c.dom.NodeList; import org.xml.sax.InputSource; /* * VSMonitor * Monitors a series of Virtual Sensors (last update time) * and creates a report shown on standard output and sent by e-mail * You can put this program in a Cron job and run it regularely to check status. * Syntax for calling: * java -jar VSMonitor.jar <config_file> <list_of_mails> * e.g. java -jar VSMonitor.jar conf/monitoring.cfg user@gmail.com admin@gmail.com * As input, a config file containing list sensors described by: * name of sensor, * timeout (expressing expected update period, for example every 1h), * gsn session address (e.g. www.server.com:22001/gsn) * and possibly a username and password, in case session requieres authentication. * See conf/monitoring.cfg for a sample file * List of e-mails used for notification are given as arguments to the program * e-mail account parameters (currently gmail only) are given in the config file * * */ public class VSMonitor { public static final String CONFIG_SEPARATOR = "@"; public static final String DEFAULT_GSN_LOG4J_PROPERTIES = "conf/log4j.properties"; private static transient final Logger logger = LoggerFactory.getLogger(VSMonitor.class); public static HashMap<String, VSensorMonitorConfig> monitoredSensors = new HashMap<String, VSensorMonitorConfig>(); public static HashMap<String, Long> sensorsUpdateDelay = new HashMap<String, Long>(); public static List<GSNSessionAddress> listOfGSNSessions = new Vector<GSNSessionAddress>(); public static List<String> listOfMails = new Vector<String>(); public static StringBuilder errorsBuffer = new StringBuilder(); public static StringBuilder warningsBuffer = new StringBuilder(); public static StringBuilder infosBuffer = new StringBuilder(); public static StringBuilder summary = new StringBuilder(); public static StringBuilder report = new StringBuilder(); private static final String GSN_REALM = "GSNRealm"; private static String gmail_username; private static String gmail_password; private static final String SMTP_GMAIL_COM = "smtp.gmail.com"; private static int nHostsDown = 0; private static int nSensorsLate = 0; /* * Reads config file and initializes: * e-mail config (gmail_username, gmail_password) * lists * - monitoredSensors: list of monitored sensors (including expected update delay) * - sensorsUpdateDelay: list of sensors update delays (initialized to -1) * - listOfGSNSessions: list of GSN sessions * */ public static void initFromFile(String fileName) { long timeout; String vsensorname; String host; String path; int port; boolean needspassword; String password; String username; logger.warn("Trying to initialize VSMonitor from file <" + fileName + ">"); try { BufferedReader in = new BufferedReader(new FileReader(fileName)); String str; while ((str = in.readLine()) != null) { // ignore comments starting with # if (str.trim().indexOf("#") == 0) { continue; } if (str.trim().indexOf("@gmail-username") >= 0) { gmail_username = str.trim().split(" ")[1]; //System.out.println("GMAIL Username: "+ gmail_username); continue; } if (str.trim().indexOf("@gmail-password") >= 0) { gmail_password = str.trim().split(" ")[1]; //System.out.println("GMAIL password: "+ gmail_password); continue; } //@gmail-username //@gmail-password String[] s = str.trim().split(CONFIG_SEPARATOR); if (s.length < 3) { logger.warn("Malformed monitoring line in file <" + fileName + "> : " + str); //System.out.println("Malformed monitoring line in file <"+ fileName + "> : "+str); } else { //System.out.println(s.length+" Elements found"); vsensorname = s[0].trim(); timeout = VSensorMonitorConfig.timeOutFromString(s[1].trim()); //System.out.println("\""+s[2]+"\""); String[] host_port_path = s[2].split(":"); //System.out.println(host_port_path.length); if (host_port_path.length != 2) { logger.warn("Malformed monitoring line in file <" + fileName + "> : " + str); //System.out.println("Malformed monitoring line in file <"+ fileName + "> : "+str); continue; } else { //System.out.println("["+host_port_path[0].trim()+"]["+host_port_path[1].trim()+"]"); host = host_port_path[0].trim(); int j = host_port_path[1].trim().indexOf("/"); String portStr = host_port_path[1].trim().substring(0, j); //System.out.println("Port:"+portStr); path = host_port_path[1].trim().substring(j); //System.out.println("Path:"+"\""+path+"\""); try { port = Integer.parseInt(portStr); //System.out.println(">>"+port); } catch (NumberFormatException e) { logger.warn("Malformed monitoring line in file <" + fileName + "> : " + str); //System.out.println("Malformed monitoring line in file <"+ fileName + "> : "+str); continue; } if (s.length > 3) { // needs password needspassword = true; String[] username_password = s[3].split(":"); if (username_password.length > 1) { username = username_password[0].trim(); password = username_password[1].trim(); } else { logger.warn("Malformed monitoring line in file <" + fileName + "> : " + str); //System.out.println("Malformed monitoring line in file <"+ fileName + "> : "+str); continue; } } else { needspassword = false; username = ""; password = ""; } // DEBUG INFO //System.out.println("TIMEOUT: "+timeout); //System.out.println("Creating object with : "+vsensorname+" "+host+" "+port+" "+timeout+" "+path+" "+needspassword+" "+username+" "+password); monitoredSensors.put(vsensorname, new VSensorMonitorConfig(vsensorname, host, port, timeout, path, needspassword, username, password)); // DEBUG INFO //System.out.println("RESULT: "+ monitoredSensors.get(vsensorname).toString()); sensorsUpdateDelay.put(vsensorname, new Long(-1)); // not yes initialized, to be initialized when web server is queried GSNSessionAddress gsnSessionAdress = new GSNSessionAddress(host, path, port, needspassword, username, password); //TODO: insitialize it if (!listOfGSNSessions.contains(gsnSessionAdress)) { listOfGSNSessions.add(gsnSessionAdress); } //System.out.println("VS: "+"\""+vsensorname+"\""+" timeout: " + Long.toString(timeout)); //System.out.println("Added: "+ monitoredSensors.get(vsensorname)); logger.warn("Added:" + monitoredSensors.get(vsensorname)); } } } } catch (IOException e) { logger.warn("IO Exception while trying to open file <" + fileName + "> " + e); } } /* * Queries a GSN session for status * Uses Http Get method to read xml status (usually under /gsn) * and initializes global variables : * - errorsBuffer * - noErrrorsBuffer * - nHostsDown * */ public static void readStatus(GSNSessionAddress gsnSessionAddress) throws Exception { String httpAddress = gsnSessionAddress.getURL(); DefaultHttpClient client = new DefaultHttpClient(); if (gsnSessionAddress.needsPassword()) { client.getCredentialsProvider().setCredentials( new AuthScope(gsnSessionAddress.getHost(), gsnSessionAddress.getPort()/*, GSN_REALM*/), new UsernamePasswordCredentials(gsnSessionAddress.getUsername(), gsnSessionAddress.getPassword())); } logger.warn("Querying server: " + httpAddress); HttpGet get = new HttpGet(httpAddress); try { // execute the GET, getting string directly ResponseHandler<String> responseHandler = new BasicResponseHandler(); String responseBody = client.execute(get, responseHandler); parseXML(responseBody); } catch (HttpResponseException e) { errorsBuffer.append("HTTP 401 Authentication Needed for : ").append(httpAddress).append("\n"); } catch (UnknownHostException e) { errorsBuffer.append("Unknown host: ").append(httpAddress).append("\n"); nHostsDown++; } catch (ConnectException e) { errorsBuffer.append("Connection refused to host: ").append(httpAddress).append("\n"); nHostsDown++; } finally { // release any connection resources used by the method client.getConnectionManager().shutdown(); } } /* * Checks update times * */ public static void checkUpdateTimes() { for (int i = 0; i < sensorsUpdateDelay.size(); i++) { Long lastUpdated = (Long) sensorsUpdateDelay.values().toArray()[i]; String sensorName = (String) sensorsUpdateDelay.keySet().toArray()[i]; if (lastUpdated.longValue() > monitoredSensors.get(sensorName).getTimeout()) { warningsBuffer.append(sensorName).append("@").append(monitoredSensors.get(sensorName).getHost()) .append(":").append(monitoredSensors.get(sensorName).getPort()).append(" not updated for ") .append(VSensorMonitorConfig.ms2dhms(sensorsUpdateDelay.get(sensorName))) .append(" (expected <") .append(VSensorMonitorConfig.ms2dhms(monitoredSensors.get(sensorName).getTimeout())) .append(")\n"); nSensorsLate++; } else { infosBuffer.append(sensorName).append("@").append(monitoredSensors.get(sensorName).getHost()) .append(":").append(monitoredSensors.get(sensorName).getPort()).append(" (on time)\n"); } } } /* * Sends an e-mail to recipients specified in command line * (through global listOfMails) * with the global summary as subject * and global errorsBuffer as body * */ private static void sendMail() throws EmailException { SimpleEmail email = new SimpleEmail(); //email.setDebug(true); email.setHostName(SMTP_GMAIL_COM); email.setAuthentication(gmail_username, gmail_password); //System.out.println(gmail_username +" "+ gmail_password); email.getMailSession().getProperties().put("mail.smtp.starttls.enable", "true"); email.getMailSession().getProperties().put("mail.smtp.auth", "true"); email.getMailSession().getProperties().put("mail.debug", "true"); email.getMailSession().getProperties().put("mail.smtp.port", "465"); email.getMailSession().getProperties().put("mail.smtp.socketFactory.port", "465"); email.getMailSession().getProperties().put("mail.smtp.socketFactory.class", "javax.net.ssl.SSLSocketFactory"); email.getMailSession().getProperties().put("mail.smtp.socketFactory.fallback", "false"); email.getMailSession().getProperties().put("mail.smtp.starttls.enable", "true"); for (String s : listOfMails) { email.addTo(s); } email.setFrom(gmail_username + "@gmail.com", gmail_username); email.setSubject("[GSN Alert] " + summary.toString()); email.setMsg(report.toString()); email.send(); } /* * parses the XML string * and initializes sensorsUpdateDelay * with update delays for relevant sensors * */ public static void parseXML(String s) { try { DocumentBuilderFactory documentBuilderFactory = DocumentBuilderFactory.newInstance(); DocumentBuilder documentBuilder = documentBuilderFactory.newDocumentBuilder(); InputSource inputSource = new InputSource(); inputSource.setCharacterStream(new StringReader(s)); Document document = documentBuilder.parse(inputSource); NodeList nodes = document.getElementsByTagName("virtual-sensor"); for (int i = 0; i < nodes.getLength(); i++) { Element element = (Element) nodes.item(i); String sensor_name = element.getAttribute("name"); if (!sensorsUpdateDelay.containsKey(sensor_name)) continue; // skip sensors that are not monitored logger.warn("Sensor: " + sensor_name); NodeList listOfField = element.getElementsByTagName("field"); for (int j = 0; j < listOfField.getLength(); j++) { Element line = (Element) listOfField.item(j); if (line.getAttribute("name").indexOf("timed") >= 0) { String last_updated_as_string = line.getTextContent(); try { Long last_updated_as_Long = GregorianCalendar.getInstance().getTimeInMillis() - VSensorMonitorConfig.datetime2timestamp(last_updated_as_string); logger.warn(new StringBuilder(last_updated_as_string).append(" => ") .append(VSensorMonitorConfig.ms2dhms(last_updated_as_Long)).toString()); sensorsUpdateDelay.put(sensor_name, last_updated_as_Long); } catch (ParseException e) { errorsBuffer.append("Last update time for sensor ").append(sensor_name) .append(" cannot be read. Error while parsing > ") .append(last_updated_as_string).append(" <\n"); } } } } } catch (Exception e) { logger.warn("Exception while parsing XML\n"); e.printStackTrace(); } } /* * Prints the stack trace of the exception to a string. * */ public static String getStackTrace(Throwable t) { StringWriter stringWriter = new StringWriter(); PrintWriter printWriter = new PrintWriter(stringWriter, true); t.printStackTrace(printWriter); printWriter.flush(); stringWriter.flush(); return stringWriter.toString(); } public static void main(String[] args) { String configFileName; if (args.length >= 2) { configFileName = args[0]; System.out.println("Using config file: " + configFileName); for (int i = 1; i < args.length; i++) { System.out.println("Adding e-mail: " + args[i]); listOfMails.add(args[i]); } } else { System.out.println("Usage java -jar VSMonitor.jar <config_file> <list_of_mails>"); System.out.println("e.g. java -jar VSMonitor.jar conf/monitoring.cfg user@gmail.com admin@gmail.com"); return; } initFromFile(configFileName); // for each monitored GSN server Iterator iter = listOfGSNSessions.iterator(); while (iter.hasNext()) { try { readStatus((GSNSessionAddress) iter.next()); } catch (Exception e) { logger.error("Exception: " + e.getMessage()); logger.error("StackTrace:\n" + getStackTrace(e)); } } checkUpdateTimes(); // Generate Report report.append("\n[ERROR]\n" + errorsBuffer).append("\n[WARNING]\n" + warningsBuffer) .append("\n[INFO]\n" + infosBuffer); if ((nSensorsLate > 0) || (nHostsDown > 0)) { summary.append("WARNING: "); if (nHostsDown > 0) summary.append(nHostsDown + " host(s) down. "); if (nSensorsLate > 0) summary.append(nSensorsLate + " sensor(s) not updated. "); // Send e-mail only if there are errors try { sendMail(); } catch (EmailException e) { logger.error("Cannot send e-mail. " + e.getMessage()); logger.error("StackTrace:\n" + getStackTrace(e)); } } // Showing report System.out.println(summary); System.out.println(report); } }