Java tutorial
/* * ==================================================================== * * The Apache Software License, Version 1.1 * * Copyright (c) 1999 The Apache Software Foundation. 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. * * 3. 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For more * information on the Apache Software Foundation, please see * <http://www.apache.org/>. * * [Additional notices, if required by prior licensing conditions] * */ package org.apache.jk.common; import java.io.BufferedInputStream; import java.io.BufferedOutputStream; import java.io.IOException; import java.io.InputStream; import java.io.OutputStream; import java.net.InetAddress; import java.net.ServerSocket; import java.net.Socket; import javax.management.ListenerNotFoundException; import javax.management.MBeanNotificationInfo; import javax.management.Notification; import javax.management.NotificationBroadcaster; import javax.management.NotificationBroadcasterSupport; import javax.management.NotificationFilter; import javax.management.NotificationListener; import javax.management.ObjectName; import org.apache.commons.modeler.Registry; import org.apache.jk.core.JkHandler; import org.apache.jk.core.Msg; import org.apache.jk.core.MsgContext; import org.apache.tomcat.util.threads.ThreadPool; import org.apache.tomcat.util.threads.ThreadPoolRunnable; /* XXX Make the 'message type' pluggable */ /* A lot of the 'original' behavior is hardcoded - this uses Ajp13 wire protocol, TCP, Ajp14 API etc. As we add other protocols/transports/APIs this will change, the current goal is to get the same level of functionality as in the original jk connector. */ /** * Jk2 can use multiple protocols/transports. * Various container adapters should load this object ( as a bean ), * set configurations and use it. Note that the connector will handle * all incoming protocols - it's not specific to ajp1x. The protocol * is abstracted by MsgContext/Message/Channel. */ /** Accept ( and send ) TCP messages. * * @author Costin Manolache * @jmx:mbean name="jk2:service=ChannelSocket" * description="Accept socket connections" * @jmx:notification name="org.apache.coyote.INVOKE * @jmx:notification-handler name="org.apache.jk.JK_SEND_PACKET * @jmx:notification-handler name="org.apache.jk.JK_RECEIVE_PACKET * @jmx:notification-handler name="org.apache.jk.JK_FLUSH */ public class ChannelSocket extends JkHandler implements NotificationBroadcaster { private static org.apache.commons.logging.Log log = org.apache.commons.logging.LogFactory .getLog(ChannelSocket.class); int startPort = 8009; int maxPort = 8019; // 0 for backward compat. int port = startPort; InetAddress inet; int serverTimeout; boolean tcpNoDelay = true; // nodelay to true by default int linger = 100; int socketTimeout; long requestCount = 0; /* Turning this to true will reduce the latency with about 20%. But it requires changes in tomcat to make sure client-requested flush() is honored ( on my test, I got 367->433 RPS and 52->35ms average time with a simple servlet ) */ static final boolean BUFFER_WRITE = false; ThreadPool tp = ThreadPool.createThreadPool(true); /* ==================== Tcp socket options ==================== */ /** * @jmx:managed-constructor description="default constructor" */ public ChannelSocket() { // This should be integrated with the domain setup } public ThreadPool getThreadPool() { return tp; } public long getRequestCount() { return requestCount; } /** Set the port for the ajp13 channel. * To support seemless load balancing and jni, we treat this * as the 'base' port - we'll try up until we find one that is not * used. We'll also provide the 'difference' to the main coyote * handler - that will be our 'sessionID' and the position in * the scoreboard and the suffix for the unix domain socket. * * @jmx:managed-attribute description="Port to listen" access="READ_WRITE" */ public void setPort(int port) { this.startPort = port; this.port = port; this.maxPort = port + 10; } public int getPort() { return port; } public void setAddress(InetAddress inet) { this.inet = inet; } /** * @jmx:managed-attribute description="Bind on a specified address" access="READ_WRITE" */ public void setAddress(String inet) { try { this.inet = InetAddress.getByName(inet); } catch (Exception ex) { ex.printStackTrace(); } } public String getAddress() { if (inet != null) return inet.toString(); return null; } /** * Sets the timeout in ms of the server sockets created by this * server. This method allows the developer to make servers * more or less responsive to having their server sockets * shut down. * * <p>By default this value is 1000ms. */ public void setServerTimeout(int timeout) { this.serverTimeout = timeout; } public int getServerTimeout() { return serverTimeout; } public void setTcpNoDelay(boolean b) { tcpNoDelay = b; } public boolean getTcpNoDelay() { return tcpNoDelay; } public void setSoLinger(int i) { linger = i; } public int getSoLinger() { return linger; } public void setSoTimeout(int i) { socketTimeout = i; } public int getSoTimeout() { return socketTimeout; } public void setMaxPort(int i) { maxPort = i; } public int getMaxPort() { return maxPort; } /** At startup we'll look for the first free port in the range. The difference between this port and the beggining of the range is the 'id'. This is usefull for lb cases ( less config ). */ public int getInstanceId() { return port - startPort; } /** If set to false, the thread pool will be created in * non-daemon mode, and will prevent main from exiting */ public void setDaemon(boolean b) { tp.setDaemon(b); } public boolean getDaemon() { return tp.getDaemon(); } public void setMaxThreads(int i) { if (log.isDebugEnabled()) log.debug("Setting maxThreads " + i); tp.setMaxThreads(i); } public int getMaxThreads() { return tp.getMaxThreads(); } public void setBacklog(int i) { } /* ==================== ==================== */ ServerSocket sSocket; int socketNote = 1; int isNote = 2; int osNote = 3; int notifNote = 4; public void accept(MsgContext ep) throws IOException { if (sSocket == null) return; Socket s = sSocket.accept(); ep.setNote(socketNote, s); if (log.isDebugEnabled()) log.debug("Accepted socket " + s); if (linger > 0) s.setSoLinger(true, linger); if (socketTimeout > 0) s.setSoTimeout(socketTimeout); s.setTcpNoDelay(tcpNoDelay); // set socket tcpnodelay state requestCount++; InputStream is = new BufferedInputStream(s.getInputStream()); OutputStream os; if (BUFFER_WRITE) os = new BufferedOutputStream(s.getOutputStream()); else os = s.getOutputStream(); ep.setNote(isNote, is); ep.setNote(osNote, os); ep.setControl(tp); } public void resetCounters() { requestCount = 0; } /** Called after you change some fields at runtime using jmx. Experimental for now. */ public void reinit() throws IOException { destroy(); init(); } /** * @jmx:managed-operation */ public void init() throws IOException { // Find a port. if (startPort == 0) { port = 0; log.info("JK2: ajp13 disabling channelSocket"); running = true; return; } if (maxPort < startPort) maxPort = startPort; if (getAddress() == null) setAddress("0.0.0.0"); for (int i = startPort; i <= maxPort; i++) { try { sSocket = new ServerSocket(i, 0, inet); port = i; break; } catch (IOException ex) { log.info("Port busy " + i + " " + ex.toString()); continue; } } if (sSocket == null) { log.error("Can't find free port " + startPort + " " + maxPort); return; } log.info("JK2: ajp13 listening on " + getAddress() + ":" + port); // If this is not the base port and we are the 'main' channleSocket and // SHM didn't already set the localId - we'll set the instance id if ("channelSocket".equals(name) && port != startPort && (wEnv.getLocalId() == 0)) { wEnv.setLocalId(port - startPort); } if (serverTimeout > 0) sSocket.setSoTimeout(serverTimeout); // XXX Reverse it -> this is a notification generator !! if (next == null && wEnv != null) { if (nextName != null) setNext(wEnv.getHandler(nextName)); if (next == null) next = wEnv.getHandler("dispatch"); if (next == null) next = wEnv.getHandler("request"); } running = true; // Run a thread that will accept connections. // XXX Try to find a thread first - not sure how... if (this.domain != null) { try { tpOName = new ObjectName(domain + ":type=ThreadPool,name=jk" + port); Registry.getRegistry().registerComponent(tp, tpOName, null); } catch (Exception e) { log.error("Can't register threadpool"); } } // XXX Move to start, make sure the caller calls start tp.start(); SocketAcceptor acceptAjp = new SocketAcceptor(this); tp.runIt(acceptAjp); } ObjectName tpOName; public void start() throws IOException { if (sSocket == null) init(); } public void stop() throws IOException { destroy(); } public void open(MsgContext ep) throws IOException { } public void close(MsgContext ep) throws IOException { Socket s = (Socket) ep.getNote(socketNote); s.close(); } public void destroy() throws IOException { running = false; try { /* If we disabled the channel return */ if (port == 0) return; tp.shutdown(); // Need to create a connection to unlock the accept(); Socket s; if (inet == null) { s = new Socket("127.0.0.1", port); } else { s = new Socket(inet, port); // setting soLinger to a small value will help shutdown the // connection quicker s.setSoLinger(true, 0); } s.close(); sSocket.close(); // XXX? if (tpOName != null) { Registry.getRegistry().unregisterComponent(tpOName); } } catch (Exception e) { log.info("Error shutting down the channel " + port + " " + e.toString()); if (log.isDebugEnabled()) log.debug("Trace", e); } } public int send(Msg msg, MsgContext ep) throws IOException { msg.end(); // Write the packet header byte buf[] = msg.getBuffer(); int len = msg.getLen(); if (log.isTraceEnabled()) log.trace("send() " + len + " " + buf[4]); OutputStream os = (OutputStream) ep.getNote(osNote); os.write(buf, 0, len); return len; } public int flush(Msg msg, MsgContext ep) throws IOException { if (BUFFER_WRITE) { OutputStream os = (OutputStream) ep.getNote(osNote); os.flush(); } return 0; } public int receive(Msg msg, MsgContext ep) throws IOException { if (log.isDebugEnabled()) { log.debug("receive() "); } byte buf[] = msg.getBuffer(); int hlen = msg.getHeaderLength(); // XXX If the length in the packet header doesn't agree with the // actual number of bytes read, it should probably return an error // value. Also, callers of this method never use the length // returned -- should probably return true/false instead. int rd = this.read(ep, buf, 0, hlen); if (rd < 0) { // Most likely normal apache restart. // log.warn("Wrong message " + rd ); return rd; } msg.processHeader(); /* After processing the header we know the body length */ int blen = msg.getLen(); // XXX check if enough space - it's assert()-ed !!! int total_read = 0; total_read = this.read(ep, buf, hlen, blen); if ((total_read <= 0) && (blen > 0)) { log.warn("can't read body, waited #" + blen); return -1; } if (total_read != blen) { log.warn("incomplete read, waited #" + blen + " got only " + total_read); return -2; } return total_read; } /** * Read N bytes from the InputStream, and ensure we got them all * Under heavy load we could experience many fragmented packets * just read Unix Network Programming to recall that a call to * read didn't ensure you got all the data you want * * from read() Linux manual * * On success, the number of bytes read is returned (zero indicates end * of file),and the file position is advanced by this number. * It is not an error if this number is smaller than the number of bytes * requested; this may happen for example because fewer bytes * are actually available right now (maybe because we were close to * end-of-file, or because we are reading from a pipe, or from a * terminal), or because read() was interrupted by a signal. * On error, -1 is returned, and errno is set appropriately. In this * case it is left unspecified whether the file position (if any) changes. * **/ public int read(MsgContext ep, byte[] b, int offset, int len) throws IOException { InputStream is = (InputStream) ep.getNote(isNote); int pos = 0; int got; while (pos < len) { got = is.read(b, pos + offset, len - pos); if (log.isTraceEnabled()) { log.trace( "read() " + b + " " + (b == null ? 0 : b.length) + " " + offset + " " + len + " = " + got); } // connection just closed by remote. if (got <= 0) { // This happens periodically, as apache restarts // periodically. // It should be more gracefull ! - another feature for Ajp14 // log.warn( "server has closed the current connection (-1)" ); return -3; } pos += got; } return pos; } protected boolean running = true; /** Accept incoming connections, dispatch to the thread pool */ void acceptConnections() { if (log.isDebugEnabled()) log.debug("Accepting ajp connections on " + port); while (running) { try { MsgContext ep = new MsgContext(); ep.setSource(this); ep.setWorkerEnv(wEnv); this.accept(ep); if (!running) break; // Since this is a long-running connection, we don't care // about the small GC SocketConnection ajpConn = new SocketConnection(this, ep); tp.runIt(ajpConn); } catch (Exception ex) { if (running) ex.printStackTrace(); } } } /** Process a single ajp connection. */ void processConnection(MsgContext ep) { try { MsgAjp recv = new MsgAjp(); while (running) { int status = this.receive(recv, ep); if (status <= 0) { if (status == -3) log.debug("server has been restarted or reset this connection"); else log.warn("Closing ajp connection " + status); break; } ep.setLong(MsgContext.TIMER_RECEIVED, System.currentTimeMillis()); ep.setType(0); // Will call next status = this.invoke(recv, ep); if (status != JkHandler.OK) { log.warn("processCallbacks status " + status); break; } } } catch (Exception ex) { if (ex.getMessage().indexOf("Connection reset") >= 0) log.debug("Server has been restarted or reset this connection"); else if (ex.getMessage().indexOf("Read timed out") >= 0) log.info("connection timeout reached"); else log.error("Error, processing connection", ex); } finally { /* * Whatever happened to this connection (remote closed it, timeout, read error) * the socket SHOULD be closed, or we may be in situation where the webserver * will continue to think the socket is still open and will forward request * to tomcat without receiving ever a reply */ try { this.close(ep); } catch (Exception e) { log.error("Error, closing connection", e); } } } // XXX This should become handleNotification public int invoke(Msg msg, MsgContext ep) throws IOException { int type = ep.getType(); switch (type) { case JkHandler.HANDLE_RECEIVE_PACKET: if (log.isDebugEnabled()) log.debug("RECEIVE_PACKET ?? "); return receive(msg, ep); case JkHandler.HANDLE_SEND_PACKET: return send(msg, ep); case JkHandler.HANDLE_FLUSH: return flush(msg, ep); } if (log.isDebugEnabled()) log.debug("Call next " + type + " " + next); // Send notification if (nSupport != null) { Notification notif = (Notification) ep.getNote(notifNote); if (notif == null) { notif = new Notification("channelSocket.message", ep, requestCount); ep.setNote(notifNote, notif); } nSupport.sendNotification(notif); } if (next != null) { return next.invoke(msg, ep); } else { log.info("No next "); } return OK; } public boolean isSameAddress(MsgContext ep) { Socket s = (Socket) ep.getNote(socketNote); return isSameAddress(s.getLocalAddress(), s.getInetAddress()); } /** * Return <code>true</code> if the specified client and server addresses * are the same. This method works around a bug in the IBM 1.1.8 JVM on * Linux, where the address bytes are returned reversed in some * circumstances. * * @param server The server's InetAddress * @param client The client's InetAddress */ public static boolean isSameAddress(InetAddress server, InetAddress client) { // Compare the byte array versions of the two addresses byte serverAddr[] = server.getAddress(); byte clientAddr[] = client.getAddress(); if (serverAddr.length != clientAddr.length) return (false); boolean match = true; for (int i = 0; i < serverAddr.length; i++) { if (serverAddr[i] != clientAddr[i]) { match = false; break; } } if (match) return (true); // Compare the reversed form of the two addresses for (int i = 0; i < serverAddr.length; i++) { if (serverAddr[i] != clientAddr[(serverAddr.length - 1) - i]) return (false); } return (true); } public void sendNewMessageNotification(Notification notification) { if (nSupport != null) nSupport.sendNotification(notification); } private NotificationBroadcasterSupport nSupport = null; public void addNotificationListener(NotificationListener listener, NotificationFilter filter, Object handback) throws IllegalArgumentException { if (nSupport == null) nSupport = new NotificationBroadcasterSupport(); nSupport.addNotificationListener(listener, filter, handback); } public void removeNotificationListener(NotificationListener listener) throws ListenerNotFoundException { if (nSupport != null) nSupport.removeNotificationListener(listener); } MBeanNotificationInfo notifInfo[] = new MBeanNotificationInfo[0]; public void setNotificationInfo(MBeanNotificationInfo info[]) { this.notifInfo = info; } public MBeanNotificationInfo[] getNotificationInfo() { return notifInfo; } } class SocketAcceptor implements ThreadPoolRunnable { ChannelSocket wajp; SocketAcceptor(ChannelSocket wajp) { this.wajp = wajp; } public Object[] getInitData() { return null; } public void runIt(Object thD[]) { wajp.acceptConnections(); } } class SocketConnection implements ThreadPoolRunnable { ChannelSocket wajp; MsgContext ep; SocketConnection(ChannelSocket wajp, MsgContext ep) { this.wajp = wajp; this.ep = ep; } public Object[] getInitData() { return null; } public void runIt(Object perTh[]) { wajp.processConnection(ep); } }