Java tutorial
/** * Licensed to the Apache Software Foundation (ASF) under one * or more contributor license agreements. See the NOTICE file * distributed with this work for additional information * regarding copyright ownership. The ASF licenses this file * to you 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 org.apache.hama.ipc; import static org.apache.hadoop.fs.CommonConfigurationKeys.HADOOP_SECURITY_AUTHORIZATION; import static org.apache.hadoop.fs.CommonConfigurationKeys.IPC_SERVER_RPC_READ_THREADS_DEFAULT; import static org.apache.hadoop.fs.CommonConfigurationKeys.IPC_SERVER_RPC_READ_THREADS_KEY; import java.io.ByteArrayInputStream; import java.io.ByteArrayOutputStream; import java.io.DataInputStream; import java.io.DataOutputStream; import java.io.IOException; import java.net.BindException; import java.net.InetAddress; import java.net.InetSocketAddress; import java.net.ServerSocket; import java.net.Socket; import java.net.SocketException; import java.net.UnknownHostException; import java.nio.ByteBuffer; import java.nio.channels.CancelledKeyException; import java.nio.channels.ClosedChannelException; import java.nio.channels.ReadableByteChannel; import java.nio.channels.SelectionKey; import java.nio.channels.Selector; import java.nio.channels.ServerSocketChannel; import java.nio.channels.SocketChannel; import java.nio.channels.WritableByteChannel; import java.security.PrivilegedExceptionAction; import java.util.ArrayList; import java.util.Collections; import java.util.HashSet; import java.util.Iterator; import java.util.LinkedList; import java.util.List; import java.util.Map; import java.util.Random; import java.util.Set; import java.util.concurrent.BlockingQueue; import java.util.concurrent.ConcurrentHashMap; import java.util.concurrent.LinkedBlockingQueue; import org.apache.commons.logging.Log; import org.apache.commons.logging.LogFactory; import org.apache.hadoop.conf.Configuration; import org.apache.hadoop.fs.CommonConfigurationKeys; import org.apache.hadoop.io.Writable; import org.apache.hadoop.io.WritableUtils; import org.apache.hadoop.security.AccessControlException; import org.apache.hadoop.security.SaslRpcServer.AuthMethod; import org.apache.hadoop.security.UserGroupInformation; import org.apache.hadoop.security.authorize.AuthorizationException; import org.apache.hadoop.security.authorize.ProxyUsers; import org.apache.hadoop.security.authorize.ServiceAuthorizationManager; import org.apache.hadoop.security.token.SecretManager; import org.apache.hadoop.security.token.TokenIdentifier; import org.apache.hadoop.util.ReflectionUtils; import org.apache.hadoop.util.StringUtils; /** * An abstract IPC service. IPC calls take a single {@link Writable} as a * parameter, and return a {@link Writable} as their value. A service runs on a * port and is defined by a parameter class and a value class. * * @see Client */ public abstract class Server { private final boolean authorize; private boolean isSecurityEnabled; private ExceptionsHandler exceptionsHandler = new ExceptionsHandler(); public void addTerseExceptions(Class<?>... exceptionClass) { exceptionsHandler.addTerseExceptions(exceptionClass); } /** * ExceptionsHandler manages Exception groups for special handling e.g., terse * exception group for concise logging messages */ static class ExceptionsHandler { private volatile Set<String> terseExceptions = new HashSet<String>(); /** * Add exception class so server won't log its stack trace. Modifying the * terseException through this method is thread safe. * * @param exceptionClass exception classes */ void addTerseExceptions(Class<?>... exceptionClass) { // Make a copy of terseException for performing modification final HashSet<String> newSet = new HashSet<String>(terseExceptions); // Add all class names into the HashSet for (Class<?> name : exceptionClass) { newSet.add(name.toString()); } // Replace terseException set terseExceptions = Collections.unmodifiableSet(newSet); } boolean isTerse(Class<?> t) { return terseExceptions.contains(t.toString()); } } /** * The first four bytes of Hadoop RPC connections */ public static final ByteBuffer HEADER = ByteBuffer.wrap("hrpc".getBytes()); // 1 : Introduce ping and server does not throw away RPCs // 3 : Introduce the protocol into the RPC connection header // 4 : Introduced SASL security layer public static final byte CURRENT_VERSION = 4; /** * How many calls/handler are allowed in the queue. */ private static final int IPC_SERVER_HANDLER_QUEUE_SIZE_DEFAULT = 100; private static final String IPC_SERVER_HANDLER_QUEUE_SIZE_KEY = "ipc.server.handler.queue.size"; /** * Initial and max size of response buffer */ static int INITIAL_RESP_BUF_SIZE = 10240; static final String IPC_SERVER_RPC_MAX_RESPONSE_SIZE_KEY = "ipc.server.max.response.size"; static final int IPC_SERVER_RPC_MAX_RESPONSE_SIZE_DEFAULT = 1024 * 1024; public static final Log LOG = LogFactory.getLog(Server.class); private static final ThreadLocal<Server> SERVER = new ThreadLocal<Server>(); private static final Map<String, Class<?>> PROTOCOL_CACHE = new ConcurrentHashMap<String, Class<?>>(); static Class<?> getProtocolClass(String protocolName, Configuration conf) throws ClassNotFoundException { Class<?> protocol = PROTOCOL_CACHE.get(protocolName); if (protocol == null) { protocol = conf.getClassByName(protocolName); PROTOCOL_CACHE.put(protocolName, protocol); } return protocol; } /** * Returns the server instance called under or null. May be called under * {@link #call(Writable, long)} implementations, and under {@link Writable} * methods of paramters and return values. Permits applications to access the * server context. */ public static Server get() { return SERVER.get(); } /** * This is set to Call object before Handler invokes an RPC and reset after * the call returns. */ private static final ThreadLocal<Call> CurCall = new ThreadLocal<Call>(); /** * Returns the remote side ip address when invoked inside an RPC Returns null * incase of an error. */ public static InetAddress getRemoteIp() { Call call = CurCall.get(); if (call != null) { return call.connection.socket.getInetAddress(); } return null; } /** * Returns remote address as a string when invoked inside an RPC. Returns null * in case of an error. */ public static String getRemoteAddress() { InetAddress addr = getRemoteIp(); return (addr == null) ? null : addr.getHostAddress(); } private String bindAddress; private int port; // port we listen on private int handlerCount; // number of handler threads private int readThreads; // number of read threads private Class<? extends Writable> paramClass; // class of call parameters private int maxIdleTime; // the maximum idle time after // which a client may be disconnected private int thresholdIdleConnections; // the number of idle connections // after which we will start // cleaning up idle // connections int maxConnectionsToNuke; // the max number of // connections to nuke // during a cleanup private Configuration conf; private int maxQueueSize; private final int maxRespSize; private int socketSendBufferSize; private final boolean tcpNoDelay; // if T then disable Nagle's Algorithm volatile private boolean running = true; // true while server runs private BlockingQueue<Call> callQueue; // queued calls private List<Connection> connectionList = Collections.synchronizedList(new LinkedList<Connection>()); // maintain a list // of client connections private Listener listener = null; private Responder responder = null; private int numConnections = 0; private Handler[] handlers = null; /** * A convenience method to bind to a given address and report better * exceptions if the address is not a valid host. * * @param socket the socket to bind * @param address the address to bind to * @param backlog the number of connections allowed in the queue * @throws BindException if the address can't be bound * @throws UnknownHostException if the address isn't a valid host name * @throws IOException other random errors from bind */ public static void bind(ServerSocket socket, InetSocketAddress address, int backlog) throws IOException { try { socket.bind(address, backlog); } catch (BindException e) { BindException bindException = new BindException( "Problem binding to " + address + " : " + e.getMessage()); bindException.initCause(e); throw bindException; } catch (SocketException e) { // If they try to bind to a different host's address, give a better // error message. if ("Unresolved address".equals(e.getMessage())) { throw new UnknownHostException("Invalid hostname for server: " + address.getHostName()); } else { throw e; } } } /** A call queued for handling. */ private static class Call { private int id; // the client's call id private Writable param; // the parameter passed private Connection connection; // connection to client private long timestamp; // the time received when response is null // the time served when response is not null private ByteBuffer response; // the response for this call public Call(int id, Writable param, Connection connection) { this.id = id; this.param = param; this.connection = connection; this.timestamp = System.currentTimeMillis(); this.response = null; } @Override public String toString() { return param.toString() + " from " + connection.toString(); } public void setResponse(ByteBuffer response) { this.response = response; } } /** Listens on the socket. Creates jobs for the handler threads */ private class Listener extends Thread { private ServerSocketChannel acceptChannel = null; // the accept channel private Selector selector = null; // the selector that we use for the server private Reader[] readers = null; private int currentReader = 0; private InetSocketAddress address; // the address we bind at private Random rand = new Random(); private long lastCleanupRunTime = 0; // the last time when a cleanup connec- // -tion (for idle connections) ran private long cleanupInterval = 10000; // the minimum interval between // two cleanup runs private int backlogLength = conf.getInt("ipc.server.listen.queue.size", 128); public Listener() throws IOException { address = new InetSocketAddress(bindAddress, port); // Create a new server socket and set to non blocking mode acceptChannel = ServerSocketChannel.open(); acceptChannel.configureBlocking(false); // Bind the server socket to the local host and port bind(acceptChannel.socket(), address, backlogLength); port = acceptChannel.socket().getLocalPort(); // Could be an ephemeral // port // create a selector; selector = Selector.open(); readers = new Reader[readThreads]; for (int i = 0; i < readThreads; i++) { Selector readSelector = Selector.open(); Reader reader = new Reader("Socket Reader #" + (i + 1) + " for port " + port, readSelector); readers[i] = reader; reader.start(); } // Register accepts on the server socket with the selector. acceptChannel.register(selector, SelectionKey.OP_ACCEPT); this.setName("IPC Server listener on " + port); this.setDaemon(true); } private class Reader extends Thread { private volatile boolean adding = false; private Selector readSelector = null; Reader(String name, Selector readSelector) { super(name); this.readSelector = readSelector; } public void run() { LOG.info("Starting " + getName()); synchronized (this) { while (running) { SelectionKey key = null; try { readSelector.select(); while (adding) { this.wait(1000); } Iterator<SelectionKey> iter = readSelector.selectedKeys().iterator(); while (iter.hasNext()) { key = iter.next(); iter.remove(); if (key.isValid()) { if (key.isReadable()) { doRead(key); } } key = null; } } catch (InterruptedException e) { if (running) { // unexpected -- log it LOG.info(getName() + " caught: " + StringUtils.stringifyException(e)); } } catch (IOException ex) { LOG.error("Error in Reader", ex); } } } } /** * This gets reader into the state that waits for the new channel to be * registered with readSelector. If it was waiting in select() the thread * will be woken up, otherwise whenever select() is called it will return * even if there is nothing to read and wait in while(adding) for * finishAdd call */ public void startAdd() { adding = true; readSelector.wakeup(); } public synchronized SelectionKey registerChannel(SocketChannel channel) throws IOException { return channel.register(readSelector, SelectionKey.OP_READ); } public synchronized void finishAdd() { adding = false; this.notify(); } void shutdown() { assert !running; readSelector.wakeup(); try { join(); } catch (InterruptedException ie) { Thread.currentThread().interrupt(); } } } /** * cleanup connections from connectionList. Choose a random range to scan * and also have a limit on the number of the connections that will be * cleanedup per run. The criteria for cleanup is the time for which the * connection was idle. If 'force' is true then all connections will be * looked at for the cleanup. */ private void cleanupConnections(boolean force) { if (force || numConnections > thresholdIdleConnections) { long currentTime = System.currentTimeMillis(); if (!force && (currentTime - lastCleanupRunTime) < cleanupInterval) { return; } int start = 0; int end = numConnections - 1; if (!force) { start = rand.nextInt() % numConnections; end = rand.nextInt() % numConnections; int temp; if (end < start) { temp = start; start = end; end = temp; } } int i = start; int numNuked = 0; while (i <= end) { Connection c; synchronized (connectionList) { try { c = connectionList.get(i); } catch (Exception e) { return; } } if (c.timedOut(currentTime)) { if (LOG.isDebugEnabled()) LOG.debug(getName() + ": disconnecting client " + c.getHostAddress()); closeConnection(c); numNuked++; end--; c = null; if (!force && numNuked == maxConnectionsToNuke) break; } else i++; } lastCleanupRunTime = System.currentTimeMillis(); } } @Override public void run() { LOG.info(getName() + ": starting"); SERVER.set(Server.this); while (running) { SelectionKey key = null; try { selector.select(); Iterator<SelectionKey> iter = selector.selectedKeys().iterator(); while (iter.hasNext()) { key = iter.next(); iter.remove(); try { if (key.isValid()) { if (key.isAcceptable()) doAccept(key); } } catch (IOException e) { } key = null; } } catch (OutOfMemoryError e) { // we can run out of memory if we have too many threads // log the event and sleep for a minute and give // some thread(s) a chance to finish LOG.warn("Out of Memory in server select", e); closeCurrentConnection(key, e); cleanupConnections(true); try { Thread.sleep(60000); } catch (Exception ie) { } } catch (Exception e) { closeCurrentConnection(key, e); } cleanupConnections(false); } LOG.info("Stopping " + this.getName()); synchronized (this) { try { acceptChannel.close(); selector.close(); } catch (IOException e) { } selector = null; acceptChannel = null; // clean up all connections while (!connectionList.isEmpty()) { closeConnection(connectionList.remove(0)); } } } private void closeCurrentConnection(SelectionKey key, Throwable e) { if (key != null) { Connection c = (Connection) key.attachment(); if (c != null) { if (LOG.isDebugEnabled()) LOG.debug(getName() + ": disconnecting client " + c.getHostAddress()); closeConnection(c); c = null; } } } InetSocketAddress getAddress() { return (InetSocketAddress) acceptChannel.socket().getLocalSocketAddress(); } void doAccept(SelectionKey key) throws IOException, OutOfMemoryError { Connection c = null; ServerSocketChannel server = (ServerSocketChannel) key.channel(); SocketChannel channel; while ((channel = server.accept()) != null) { channel.configureBlocking(false); channel.socket().setTcpNoDelay(tcpNoDelay); Reader reader = getReader(); try { reader.startAdd(); SelectionKey readKey = reader.registerChannel(channel); c = new Connection(readKey, channel, System.currentTimeMillis()); readKey.attach(c); synchronized (connectionList) { connectionList.add(numConnections, c); numConnections++; } if (LOG.isDebugEnabled()) LOG.debug("Server connection from " + c.toString() + "; # active connections: " + numConnections + "; # queued calls: " + callQueue.size()); } finally { reader.finishAdd(); } } } void doRead(SelectionKey key) throws InterruptedException { int count = 0; Connection c = (Connection) key.attachment(); if (c == null) { return; } c.setLastContact(System.currentTimeMillis()); try { count = c.readAndProcess(); } catch (InterruptedException ieo) { LOG.info(getName() + ": readAndProcess caught InterruptedException", ieo); throw ieo; } catch (Exception e) { LOG.info(getName() + ": readAndProcess threw exception " + e + ". Count of bytes read: " + count, e); count = -1; // so that the (count < 0) block is executed } if (count < 0) { if (LOG.isDebugEnabled()) LOG.debug(getName() + ": disconnecting client " + c + ". Number of active connections: " + numConnections); closeConnection(c); c = null; } else { c.setLastContact(System.currentTimeMillis()); } } synchronized void doStop() { if (selector != null) { selector.wakeup(); Thread.yield(); } if (acceptChannel != null) { try { acceptChannel.socket().close(); } catch (IOException e) { LOG.info(getName() + ":Exception in closing listener socket. " + e); } } for (Reader r : readers) { r.shutdown(); } } // The method that will return the next reader to work with // Simplistic implementation of round robin for now Reader getReader() { currentReader = (currentReader + 1) % readers.length; return readers[currentReader]; } } // Sends responses of RPC back to clients. private class Responder extends Thread { private Selector writeSelector; private int pending; // connections waiting to register final static int PURGE_INTERVAL = 900000; // 15mins Responder() throws IOException { this.setName("IPC Server Responder"); this.setDaemon(true); writeSelector = Selector.open(); // create a selector pending = 0; } @Override public void run() { LOG.info(getName() + ": starting"); SERVER.set(Server.this); long lastPurgeTime = 0; // last check for old calls. while (running) { try { waitPending(); // If a channel is being registered, wait. writeSelector.select(PURGE_INTERVAL); Iterator<SelectionKey> iter = writeSelector.selectedKeys().iterator(); while (iter.hasNext()) { SelectionKey key = iter.next(); iter.remove(); try { if (key.isValid() && key.isWritable()) { doAsyncWrite(key); } } catch (IOException e) { LOG.info(getName() + ": doAsyncWrite threw exception " + e); } } long now = System.currentTimeMillis(); if (now < lastPurgeTime + PURGE_INTERVAL) { continue; } lastPurgeTime = now; // // If there were some calls that have not been sent out for a // long time, discard them. // LOG.debug("Checking for old call responses."); ArrayList<Call> calls; // get the list of channels from list of keys. synchronized (writeSelector.keys()) { calls = new ArrayList<Call>(writeSelector.keys().size()); iter = writeSelector.keys().iterator(); while (iter.hasNext()) { SelectionKey key = iter.next(); Call call = (Call) key.attachment(); if (call != null && key.channel() == call.connection.channel) { calls.add(call); } } } for (Call call : calls) { try { doPurge(call, now); } catch (IOException e) { LOG.warn("Error in purging old calls " + e); } } } catch (OutOfMemoryError e) { // // we can run out of memory if we have too many threads // log the event and sleep for a minute and give // some thread(s) a chance to finish // LOG.warn("Out of Memory in server select", e); try { Thread.sleep(60000); } catch (Exception ie) { } } catch (Exception e) { LOG.warn("Exception in Responder " + StringUtils.stringifyException(e)); } } LOG.info("Stopping " + this.getName()); } private void doAsyncWrite(SelectionKey key) throws IOException { Call call = (Call) key.attachment(); if (call == null) { return; } if (key.channel() != call.connection.channel) { throw new IOException("doAsyncWrite: bad channel"); } synchronized (call.connection.responseQueue) { if (processResponse(call.connection.responseQueue, false)) { try { key.interestOps(0); } catch (CancelledKeyException e) { /* * The Listener/reader might have closed the socket. We don't * explicitly cancel the key, so not sure if this will ever fire. * This warning could be removed. */ LOG.warn("Exception while changing ops : " + e); } } } } // // Remove calls that have been pending in the responseQueue // for a long time. // private void doPurge(Call call, long now) throws IOException { LinkedList<Call> responseQueue = call.connection.responseQueue; synchronized (responseQueue) { Iterator<Call> iter = responseQueue.listIterator(0); while (iter.hasNext()) { call = iter.next(); if (now > call.timestamp + PURGE_INTERVAL) { closeConnection(call.connection); break; } } } } // Processes one response. Returns true if there are no more pending // data for this channel. // private boolean processResponse(LinkedList<Call> responseQueue, boolean inHandler) throws IOException { boolean error = true; boolean done = false; // there is more data for this channel. int numElements = 0; Call call = null; try { synchronized (responseQueue) { // // If there are no items for this channel, then we are done // numElements = responseQueue.size(); if (numElements == 0) { error = false; return true; // no more data for this channel. } // // Extract the first call // call = responseQueue.removeFirst(); SocketChannel channel = call.connection.channel; if (LOG.isDebugEnabled()) { LOG.debug(getName() + ": responding to #" + call.id + " from " + call.connection); } // // Send as much data as we can in the non-blocking fashion // int numBytes = channelWrite(channel, call.response); if (numBytes < 0) { return true; } if (!call.response.hasRemaining()) { call.connection.decRpcCount(); if (numElements == 1) { // last call fully processes. done = true; // no more data for this channel. } else { done = false; // more calls pending to be sent. } if (LOG.isDebugEnabled()) { LOG.debug(getName() + ": responding to #" + call.id + " from " + call.connection + " Wrote " + numBytes + " bytes."); } } else { // // If we were unable to write the entire response out, then // insert in Selector queue. // call.connection.responseQueue.addFirst(call); if (inHandler) { // set the serve time when the response has to be sent later call.timestamp = System.currentTimeMillis(); incPending(); try { // Wakeup the thread blocked on select, only then can the call // to channel.register() complete. writeSelector.wakeup(); channel.register(writeSelector, SelectionKey.OP_WRITE, call); } catch (ClosedChannelException e) { // Its ok. channel might be closed else where. done = true; } finally { decPending(); } } if (LOG.isDebugEnabled()) { LOG.debug(getName() + ": responding to #" + call.id + " from " + call.connection + " Wrote partial " + numBytes + " bytes."); } } error = false; // everything went off well } } finally { if (error && call != null) { LOG.warn(getName() + ", call " + call + ": output error"); done = true; // error. no more data for this channel. closeConnection(call.connection); } } return done; } // // Enqueue a response from the application. // void doRespond(Call call) throws IOException { synchronized (call.connection.responseQueue) { call.connection.responseQueue.addLast(call); if (call.connection.responseQueue.size() == 1) { processResponse(call.connection.responseQueue, true); } } } private synchronized void incPending() { // call waiting to be enqueued. pending++; } private synchronized void decPending() { // call done enqueueing. pending--; notify(); } private synchronized void waitPending() throws InterruptedException { while (pending > 0) { wait(); } } } /** Reads calls from a connection and queues them for handling. */ public class Connection { private boolean rpcHeaderRead = false; // if initial rpc header is read private boolean headerRead = false; // if the connection header that // follows version is read. private SocketChannel channel; private ByteBuffer data; private ByteBuffer dataLengthBuffer; private LinkedList<Call> responseQueue; private volatile int rpcCount = 0; // number of outstanding rpcs private long lastContact; private int dataLength; private Socket socket; // Cache the remote host & port info so that even if the socket is // disconnected, we can say where it used to connect to. private String hostAddress; private int remotePort; private InetAddress addr; ConnectionHeader header = new ConnectionHeader(); Class<?> protocol; private AuthMethod authMethod; private boolean skipInitialSaslHandshake; private ByteBuffer rpcHeaderBuffer; UserGroupInformation user = null; public UserGroupInformation attemptingUser = null; // user name before auth // Fake 'call' for failed authorization response private final int AUTHROIZATION_FAILED_CALLID = -1; private final Call authFailedCall = new Call(AUTHROIZATION_FAILED_CALLID, null, this); private ByteArrayOutputStream authFailedResponse = new ByteArrayOutputStream(); private boolean useWrap = false; public Connection(SelectionKey key, SocketChannel channel, long lastContact) { this.channel = channel; this.lastContact = lastContact; this.data = null; this.dataLengthBuffer = ByteBuffer.allocate(4); this.socket = channel.socket(); this.addr = socket.getInetAddress(); if (addr == null) { this.hostAddress = "*Unknown*"; } else { this.hostAddress = addr.getHostAddress(); } this.remotePort = socket.getPort(); this.responseQueue = new LinkedList<Call>(); if (socketSendBufferSize != 0) { try { socket.setSendBufferSize(socketSendBufferSize); } catch (IOException e) { LOG.warn("Connection: unable to set socket send buffer size to " + socketSendBufferSize); } } } @Override public String toString() { return getHostAddress() + ":" + remotePort; } public String getHostAddress() { return hostAddress; } public InetAddress getHostInetAddress() { return addr; } public void setLastContact(long lastContact) { this.lastContact = lastContact; } public long getLastContact() { return lastContact; } /* Return true if the connection has no outstanding rpc */ private boolean isIdle() { return rpcCount == 0; } /* Decrement the outstanding RPC count */ private void decRpcCount() { rpcCount--; } /* Increment the outstanding RPC count */ private void incRpcCount() { rpcCount++; } private boolean timedOut(long currentTime) { if (isIdle() && currentTime - lastContact > maxIdleTime) return true; return false; } public int readAndProcess() throws IOException, InterruptedException { while (true) { /* * Read at most one RPC. If the header is not read completely yet then * iterate until we read first RPC or until there is no data left. */ int count = -1; if (dataLengthBuffer.remaining() > 0) { count = channelRead(channel, dataLengthBuffer); if (count < 0 || dataLengthBuffer.remaining() > 0) return count; } if (!rpcHeaderRead) { // Every connection is expected to send the header. if (rpcHeaderBuffer == null) { rpcHeaderBuffer = ByteBuffer.allocate(2); } count = channelRead(channel, rpcHeaderBuffer); if (count < 0 || rpcHeaderBuffer.remaining() > 0) { return count; } int version = rpcHeaderBuffer.get(0); byte[] method = new byte[] { rpcHeaderBuffer.get(1) }; authMethod = AuthMethod.read(new DataInputStream(new ByteArrayInputStream(method))); dataLengthBuffer.flip(); if (!HEADER.equals(dataLengthBuffer) || version != CURRENT_VERSION) { // Warning is ok since this is not supposed to happen. LOG.warn("Incorrect header or version mismatch from " + hostAddress + ":" + remotePort + " got version " + version + " expected version " + CURRENT_VERSION); return -1; } dataLengthBuffer.clear(); if (authMethod == null) { throw new IOException("Unable to read authentication method"); } if (isSecurityEnabled && authMethod == AuthMethod.SIMPLE) { AccessControlException ae = new AccessControlException( "Authorization (" + CommonConfigurationKeys.HADOOP_SECURITY_AUTHORIZATION + ") is enabled but authentication (" + CommonConfigurationKeys.HADOOP_SECURITY_AUTHENTICATION + ") is configured as simple. Please configure another method " + "like kerberos or digest."); setupResponse(authFailedResponse, authFailedCall, Status.FATAL, null, ae.getClass().getName(), ae.getMessage()); responder.doRespond(authFailedCall); throw ae; } if (!isSecurityEnabled && authMethod != AuthMethod.SIMPLE) { authMethod = AuthMethod.SIMPLE; // client has already sent the initial Sasl message and we // should ignore it. Both client and server should fall back // to simple auth from now on. skipInitialSaslHandshake = true; } rpcHeaderBuffer = null; rpcHeaderRead = true; continue; } if (data == null) { dataLengthBuffer.flip(); dataLength = dataLengthBuffer.getInt(); if (dataLength == Client.PING_CALL_ID) { if (!useWrap) { // covers the !useSasl too dataLengthBuffer.clear(); return 0; // ping message } } if (dataLength < 0) { LOG.warn("Unexpected data length " + dataLength + "!! from " + getHostAddress()); } data = ByteBuffer.allocate(dataLength); } count = channelRead(channel, data); if (data.remaining() == 0) { dataLengthBuffer.clear(); data.flip(); if (skipInitialSaslHandshake) { data = null; skipInitialSaslHandshake = false; continue; } boolean isHeaderRead = headerRead; processOneRpc(data.array()); data = null; if (!isHeaderRead) { continue; } } return count; } } // / Reads the connection header following version private void processHeader(byte[] buf) throws IOException { DataInputStream in = new DataInputStream(new ByteArrayInputStream(buf)); header.readFields(in); try { String protocolClassName = header.getProtocol(); if (protocolClassName != null) { protocol = getProtocolClass(header.getProtocol(), conf); } } catch (ClassNotFoundException cnfe) { throw new IOException("Unknown protocol: " + header.getProtocol()); } UserGroupInformation protocolUser = header.getUgi(); user = protocolUser; /* if (user != null) { user.setAuthenticationMethod(AuthMethod.SIMPLE.authenticationMethod); } */ } private void processOneRpc(byte[] buf) throws IOException, InterruptedException { if (headerRead) { processData(buf); } else { processHeader(buf); headerRead = true; if (!authorizeConnection()) { throw new AccessControlException("Connection from " + this + " for protocol " + header.getProtocol() + " is unauthorized for user " + user); } } } private void processData(byte[] buf) throws IOException, InterruptedException { DataInputStream dis = new DataInputStream(new ByteArrayInputStream(buf)); int id = dis.readInt(); // try to read an id if (LOG.isDebugEnabled()) LOG.debug(" got #" + id); Writable param = ReflectionUtils.newInstance(paramClass, conf);// read // param param.readFields(dis); Call call = new Call(id, param, this); callQueue.put(call); // queue the call; maybe blocked here incRpcCount(); // Increment the rpc count } private boolean authorizeConnection() throws IOException { try { // If auth method is DIGEST, the token was obtained by the // real user for the effective user, therefore not required to // authorize real user. doAs is allowed only for simple or kerberos // authentication if (user != null && user.getRealUser() != null && (authMethod != AuthMethod.DIGEST)) { ProxyUsers.authorize(user, this.getHostAddress(), conf); } authorize(user, header, getHostInetAddress()); if (LOG.isDebugEnabled()) { LOG.debug("Successfully authorized " + header); } } catch (AuthorizationException ae) { setupResponse(authFailedResponse, authFailedCall, Status.FATAL, null, ae.getClass().getName(), ae.getMessage()); responder.doRespond(authFailedCall); return false; } return true; } private synchronized void close() throws IOException { data = null; dataLengthBuffer = null; if (!channel.isOpen()) return; try { socket.shutdownOutput(); } catch (Exception e) { } if (channel.isOpen()) { try { channel.close(); } catch (Exception e) { } } try { socket.close(); } catch (Exception e) { } } } /** Handles queued calls . */ private class Handler extends Thread { public Handler(int instanceNumber) { this.setDaemon(true); this.setName("IPC Server handler " + instanceNumber + " on " + port); } @Override public void run() { LOG.info(getName() + ": starting"); SERVER.set(Server.this); ByteArrayOutputStream buf = new ByteArrayOutputStream(INITIAL_RESP_BUF_SIZE); while (running) { try { final Call call = callQueue.take(); // pop the queue; maybe blocked // here if (LOG.isDebugEnabled()) LOG.debug(getName() + ": has #" + call.id + " from " + call.connection); String errorClass = null; String error = null; Writable value = null; CurCall.set(call); try { // Make the call as the user via Subject.doAs, thus associating // the call with the Subject if (call.connection.user == null) { value = call(call.connection.protocol, call.param, call.timestamp); } else { value = call.connection.user.doAs(new PrivilegedExceptionAction<Writable>() { @Override public Writable run() throws Exception { // make the call return call(call.connection.protocol, call.param, call.timestamp); } }); } } catch (Throwable e) { String logMsg = getName() + ", call " + call + ": error: " + e; if (e instanceof RuntimeException || e instanceof Error) { // These exception types indicate something is probably wrong // on the server side, as opposed to just a normal exceptional // result. LOG.warn(logMsg, e); } else if (exceptionsHandler.isTerse(e.getClass())) { // Don't log the whole stack trace of these exceptions. // Way too noisy! LOG.info(logMsg); } else { LOG.info(logMsg, e); } errorClass = e.getClass().getName(); error = StringUtils.stringifyException(e); } CurCall.set(null); synchronized (call.connection.responseQueue) { // setupResponse() needs to be sync'ed together with // responder.doResponse() since setupResponse may use // SASL to encrypt response data and SASL enforces // its own message ordering. setupResponse(buf, call, (error == null) ? Status.SUCCESS : Status.ERROR, value, errorClass, error); // Discard the large buf and reset it back to // smaller size to freeup heap if (buf.size() > maxRespSize) { LOG.warn("Large response size " + buf.size() + " for call " + call.toString()); buf = new ByteArrayOutputStream(INITIAL_RESP_BUF_SIZE); } responder.doRespond(call); } } catch (InterruptedException e) { if (running) { // unexpected -- log it LOG.info(getName() + " caught: " + StringUtils.stringifyException(e)); } } catch (Exception e) { LOG.info(getName() + " caught: " + StringUtils.stringifyException(e)); } } LOG.info(getName() + ": exiting"); } } protected Server(String bindAddress, int port, Class<? extends Writable> paramClass, int handlerCount, Configuration conf) throws IOException { this(bindAddress, port, paramClass, handlerCount, conf, Integer.toString(port), null); } protected Server(String bindAddress, int port, Class<? extends Writable> paramClass, int handlerCount, Configuration conf, String serverName) throws IOException { this(bindAddress, port, paramClass, handlerCount, conf, serverName, null); } /** * Constructs a server listening on the named port and address. Parameters * passed must be of the named class. The * <code>handlerCount</handlerCount> determines * the number of handler threads that will be used to process calls. * */ protected Server(String bindAddress, int port, Class<? extends Writable> paramClass, int handlerCount, Configuration conf, String serverName, SecretManager<? extends TokenIdentifier> secretManager) throws IOException { this.bindAddress = bindAddress; this.conf = conf; this.port = port; this.paramClass = paramClass; this.handlerCount = handlerCount; this.socketSendBufferSize = 0; this.maxQueueSize = handlerCount * conf.getInt(IPC_SERVER_HANDLER_QUEUE_SIZE_KEY, IPC_SERVER_HANDLER_QUEUE_SIZE_DEFAULT); this.maxRespSize = conf.getInt(IPC_SERVER_RPC_MAX_RESPONSE_SIZE_KEY, IPC_SERVER_RPC_MAX_RESPONSE_SIZE_DEFAULT); this.readThreads = conf.getInt(IPC_SERVER_RPC_READ_THREADS_KEY, IPC_SERVER_RPC_READ_THREADS_DEFAULT); this.callQueue = new LinkedBlockingQueue<Call>(maxQueueSize); this.maxIdleTime = 2 * conf.getInt("ipc.client.connection.maxidletime", 1000); this.maxConnectionsToNuke = conf.getInt("ipc.client.kill.max", 10); this.thresholdIdleConnections = conf.getInt("ipc.client.idlethreshold", 4000); this.authorize = conf.getBoolean(HADOOP_SECURITY_AUTHORIZATION, false); this.isSecurityEnabled = UserGroupInformation.isSecurityEnabled(); // Start the listener here and let it bind to the port listener = new Listener(); this.port = listener.getAddress().getPort(); this.tcpNoDelay = conf.getBoolean("ipc.server.tcpnodelay", false); // Create the responder here responder = new Responder(); } private void closeConnection(Connection connection) { synchronized (connectionList) { if (connectionList.remove(connection)) numConnections--; } try { connection.close(); } catch (IOException e) { } } /** * Setup response for the IPC Call. * * @param response buffer to serialize the response into * @param call {@link Call} to which we are setting up the response * @param status {@link Status} of the IPC call * @param rv return value for the IPC Call, if the call was successful * @param errorClass error class, if the the call failed * @param error error message, if the call failed * @throws IOException */ private void setupResponse(ByteArrayOutputStream response, Call call, Status status, Writable rv, String errorClass, String error) throws IOException { response.reset(); DataOutputStream out = new DataOutputStream(response); out.writeInt(call.id); // write call id out.writeInt(status.state); // write status if (status == Status.SUCCESS) { rv.write(out); } else { WritableUtils.writeString(out, errorClass); WritableUtils.writeString(out, error); } call.setResponse(ByteBuffer.wrap(response.toByteArray())); } Configuration getConf() { return conf; } /** for unit testing only, should be called before server is started */ void disableSecurity() { this.isSecurityEnabled = false; } /** for unit testing only, should be called before server is started */ void enableSecurity() { this.isSecurityEnabled = true; } /** Sets the socket buffer size used for responding to RPCs */ public void setSocketSendBufSize(int size) { this.socketSendBufferSize = size; } /** Starts the service. Must be called before any calls will be handled. */ public synchronized void start() { responder.start(); listener.start(); handlers = new Handler[handlerCount]; for (int i = 0; i < handlerCount; i++) { handlers[i] = new Handler(i); handlers[i].start(); } } /** Stops the service. No new calls will be handled after this is called. */ public synchronized void stop() { LOG.info("Stopping server on " + port); running = false; if (handlers != null) { for (int i = 0; i < handlerCount; i++) { if (handlers[i] != null) { handlers[i].interrupt(); } } } listener.interrupt(); listener.doStop(); responder.interrupt(); notifyAll(); } /** * Wait for the server to be stopped. Does not wait for all subthreads to * finish. See {@link #stop()}. */ public synchronized void join() throws InterruptedException { while (running) { wait(); } } /** * Return the socket (ip+port) on which the RPC server is listening to. * * @return the socket (ip+port) on which the RPC server is listening to. */ public synchronized InetSocketAddress getListenerAddress() { return listener.getAddress(); } /** * Called for each call. * * @deprecated Use {@link #call(Class, Writable, long)} instead */ @Deprecated public Writable call(Writable param, long receiveTime) throws IOException { return call(null, param, receiveTime); } /** Called for each call. */ public abstract Writable call(Class<?> protocol, Writable param, long receiveTime) throws IOException; /** * Authorize the incoming client connection. * * @param user client user * @param connection incoming connection * @param addr InetAddress of incoming connection * @throws AuthorizationException when the client isn't authorized to talk the * protocol */ @SuppressWarnings("static-access") public void authorize(UserGroupInformation user, ConnectionHeader connection, InetAddress addr) throws AuthorizationException { if (authorize) { Class<?> protocol = null; try { protocol = getProtocolClass(connection.getProtocol(), getConf()); } catch (ClassNotFoundException cfne) { throw new AuthorizationException("Unknown protocol: " + connection.getProtocol()); } ServiceAuthorizationManager authManager = new ServiceAuthorizationManager(); authManager.authorize(user, protocol, getConf(), addr); } } /** * The number of open RPC conections * * @return the number of open rpc connections */ public int getNumOpenConnections() { return numConnections; } /** * The number of rpc calls in the queue. * * @return The number of rpc calls in the queue. */ public int getCallQueueLen() { return callQueue.size(); } /** * When the read or write buffer size is larger than this limit, i/o will be * done in chunks of this size. Most RPC requests and responses would be be * smaller. */ private static int NIO_BUFFER_LIMIT = 8 * 1024; // should not be more than // 64KB. /** * This is a wrapper around {@link WritableByteChannel#write(ByteBuffer)}. If * the amount of data is large, it writes to channel in smaller chunks. This * is to avoid jdk from creating many direct buffers as the size of buffer * increases. This also minimizes extra copies in NIO layer as a result of * multiple write operations required to write a large buffer. * * @see WritableByteChannel#write(ByteBuffer) */ private int channelWrite(WritableByteChannel channel, ByteBuffer buffer) throws IOException { int count = (buffer.remaining() <= NIO_BUFFER_LIMIT) ? channel.write(buffer) : channelIO(null, channel, buffer); return count; } /** * This is a wrapper around {@link ReadableByteChannel#read(ByteBuffer)}. If * the amount of data is large, it writes to channel in smaller chunks. This * is to avoid jdk from creating many direct buffers as the size of ByteBuffer * increases. There should not be any performance degredation. * * @see ReadableByteChannel#read(ByteBuffer) */ private int channelRead(ReadableByteChannel channel, ByteBuffer buffer) throws IOException { int count = (buffer.remaining() <= NIO_BUFFER_LIMIT) ? channel.read(buffer) : channelIO(channel, null, buffer); return count; } /** * Helper for {@link #channelRead(ReadableByteChannel, ByteBuffer)} and * {@link #channelWrite(WritableByteChannel, ByteBuffer)}. Only one of readCh * or writeCh should be non-null. * * @see #channelRead(ReadableByteChannel, ByteBuffer) * @see #channelWrite(WritableByteChannel, ByteBuffer) */ private static int channelIO(ReadableByteChannel readCh, WritableByteChannel writeCh, ByteBuffer buf) throws IOException { int originalLimit = buf.limit(); int initialRemaining = buf.remaining(); int ret = 0; while (buf.remaining() > 0) { try { int ioSize = Math.min(buf.remaining(), NIO_BUFFER_LIMIT); buf.limit(buf.position() + ioSize); ret = (readCh == null) ? writeCh.write(buf) : readCh.read(buf); if (ret < ioSize) { break; } } finally { buf.limit(originalLimit); } } int nBytes = initialRemaining - buf.remaining(); return (nBytes > 0) ? nBytes : ret; } }