eu.stratosphere.nephele.ipc.Server Maven / Gradle / Ivy
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/***********************************************************************************************************************
* Copyright (C) 2010-2013 by the Stratosphere project (http://stratosphere.eu)
*
* Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on
* an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the
* specific language governing permissions and limitations under the License.
**********************************************************************************************************************/
/**
* This file is based on source code from the Hadoop Project (http://hadoop.apache.org/), licensed by the Apache
* Software Foundation (ASF) under the Apache License, Version 2.0. See the NOTICE file distributed with this work for
* additional information regarding copyright ownership.
*/
package eu.stratosphere.nephele.ipc;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.IOException;
import java.lang.reflect.Constructor;
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.util.ArrayList;
import java.util.Collections;
import java.util.Iterator;
import java.util.LinkedList;
import java.util.List;
import java.util.Map;
import java.util.Random;
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 eu.stratosphere.core.io.IOReadableWritable;
import eu.stratosphere.core.io.StringRecord;
import eu.stratosphere.core.protocols.VersionedProtocol;
import eu.stratosphere.util.ClassUtils;
/**
* 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 {
public static final Log LOG = LogFactory.getLog(Server.class);
private static final Class[] EMPTY_ARRAY = new Class[] {};
public static final ByteBuffer HEADER = ByteBuffer.wrap("crpc".getBytes());
/**
* How many calls/handler are allowed in the queue.
*/
private static final int MAX_QUEUE_SIZE_PER_HANDLER = 100;
private static final ThreadLocal SERVER = new ThreadLocal();
private static final Map> PROTOCOL_CACHE = new ConcurrentHashMap>();
static Class getProtocolClass(String protocolName) throws ClassNotFoundException {
Class protocol = PROTOCOL_CACHE.get(protocolName);
if (protocol == null) {
protocol = (Class) ClassUtils.getProtocolByName(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 CurCall = new ThreadLocal();
/**
* 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 Class invocationClass; // invocation class to call
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 int maxQueueSize;
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 callQueue; // queued calls
private List connectionList = Collections.synchronizedList(new LinkedList());
// 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 IOReadableWritable 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, IOReadableWritable 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 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 = 128;
private volatile boolean shutDown = false;
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();
// 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);
}
/**
* 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)) {
closeConnection(c);
numNuked++;
end--;
c = null;
if (!force && numNuked == maxConnectionsToNuke) {
break;
}
} else {
i++;
}
}
lastCleanupRunTime = System.currentTimeMillis();
}
}
@Override
public void run() {
LOG.debug(getName() + ": starting");
SERVER.set(Server.this);
while (running) {
SelectionKey key = null;
try {
selector.select();
Iterator iter = selector.selectedKeys().iterator();
while (iter.hasNext()) {
key = iter.next();
iter.remove();
try {
if (key.isValid()) {
if (key.isAcceptable()) {
doAccept(key);
} else if (key.isReadable()) {
doRead(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 (InterruptedException e) {
if (running) { // unexpected -- log it
LOG.info(getName() + " caught: " + e.toString());
}
} catch (Exception e) {
closeCurrentConnection(key, e);
}
cleanupConnections(false);
}
LOG.debug("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));
}
}
this.shutDown = true;
}
public boolean isShutDown() {
return this.shutDown;
}
private void closeCurrentConnection(SelectionKey key, Throwable e) {
if (key != null) {
Connection c = (Connection) key.attachment();
if (c != null) {
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();
// accept up to 10 connections
for (int i = 0; i < 10; i++) {
SocketChannel channel = server.accept();
if (channel == null) {
return;
}
channel.configureBlocking(false);
channel.socket().setTcpNoDelay(tcpNoDelay);
SelectionKey readKey = channel.register(selector, SelectionKey.OP_READ);
c = new Connection(readKey, channel, System.currentTimeMillis());
readKey.attach(c);
synchronized (connectionList) {
connectionList.add(numConnections, c);
numConnections++;
}
}
}
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) {
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);
}
}
}
}
// 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
private volatile boolean shutDown = false;
Responder()
throws IOException {
this.setName("IPC Server Responder");
this.setDaemon(true);
writeSelector = Selector.open(); // create a selector
pending = 0;
}
@Override
public void run() {
LOG.debug(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 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.
//
ArrayList calls;
// get the list of channels from list of keys.
synchronized (writeSelector.keys()) {
calls = new ArrayList(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 " + e.toString());
}
}
LOG.debug("Stopping " + this.getName());
this.shutDown = true;
}
public boolean isShutDown() {
return this.shutDown;
}
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 responseQueue = call.connection.responseQueue;
synchronized (responseQueue) {
Iterator 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 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;
//
// 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.
}
} 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();
}
}
}
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. */
private class Connection {
private boolean headerRead = false; // if the connection header that
// follows version is read.
private boolean protocolRead = false;
private SocketChannel channel;
private ByteBuffer data;
private ByteBuffer dataLengthBuffer;
private LinkedList 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;
ConnectionHeader header = new ConnectionHeader();
Class protocol;
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();
InetAddress addr = socket.getInetAddress();
if (addr == null) {
this.hostAddress = "*Unknown*";
} else {
this.hostAddress = addr.getHostAddress();
}
this.remotePort = socket.getPort();
this.responseQueue = new LinkedList();
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 void setLastContact(long lastContact) {
this.lastContact = 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 (!headerRead) {
dataLengthBuffer.flip();
if (!HEADER.equals(dataLengthBuffer)) {
// Warning is ok since this is not supposed to happen.
LOG.warn("Incorrect header from " + hostAddress + ":" + remotePort);
return -1;
}
dataLengthBuffer.clear();
headerRead = true;
continue;
}
if (data == null) {
dataLengthBuffer.flip();
dataLength = dataLengthBuffer.getInt();
if (dataLength == Client.PING_CALL_ID) {
dataLengthBuffer.clear();
return 0; // ping message
}
data = ByteBuffer.allocate(dataLength);
incRpcCount(); // Increment the rpc count
}
count = channelRead(channel, data);
if (data.remaining() == 0) {
dataLengthBuffer.clear();
data.flip();
if (protocolRead) {
processData();
data = null;
return count;
} else {
processProtocol();
protocolRead = true;
data = null;
// Authorizitation is intenionally left out
continue;
}
}
return count;
}
}
// / Reads the connection header following version
private void processProtocol() throws IOException {
DataInputStream in = new DataInputStream(new ByteArrayInputStream(data.array()));
header.read(in);
try {
String protocolClassName = header.getProtocol();
if (protocolClassName != null) {
protocol = getProtocolClass(header.getProtocol());
}
} catch (ClassNotFoundException cnfe) {
LOG.error(cnfe);
throw new IOException("Unknown protocol: " + header.getProtocol());
}
}
private void processData() throws IOException, InterruptedException {
DataInputStream dis = new DataInputStream(new ByteArrayInputStream(data.array()));
int id = dis.readInt(); // try to read an id
IOReadableWritable invocation = newInstance(invocationClass); // read param
invocation.read(dis);
Call call = new Call(id, invocation, this);
callQueue.put(call); // queue the call; maybe blocked here
}
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 {
private volatile boolean shutDown = false;
public Handler(int instanceNumber) {
this.setDaemon(true);
this.setName("IPC Server handler " + instanceNumber + " on " + port);
}
@Override
public void run() {
LOG.debug(getName() + ": starting");
SERVER.set(Server.this);
ByteArrayOutputStream buf = new ByteArrayOutputStream(10240);
while (running) {
try {
final Call call = callQueue.take(); // pop the queue; maybe blocked here
String errorClass = null;
String error = null;
IOReadableWritable value = null;
CurCall.set(call);
value = call(call.connection.protocol, call.param, call.timestamp);
CurCall.set(null);
setupResponse(buf, call, (error == null) ? Status.SUCCESS : Status.ERROR, value, errorClass, error);
responder.doRespond(call);
} catch (InterruptedException e) {
if (running) { // unexpected -- log it
LOG.error(getName() + " caught: ", e);
}
} catch (Exception e) {
LOG.error(getName() + " caught: ", e);
}
}
LOG.debug(getName() + ": exiting");
this.shutDown = true;
}
public boolean isShutDown() {
return this.shutDown;
}
}
protected Server(String bindAddress, int port, Class paramClass, int handlerCount)
throws IOException {
this(bindAddress, port, paramClass, handlerCount, Integer.toString(port));
}
/**
* Constructs a server listening on the named port and address. Parameters passed must
* be of the named class. The handlerCount determines
* the number of handler threads that will be used to process calls.
*/
protected Server(String bindAddress, int port, Class invocationClass,
int handlerCount, String serverName)
throws IOException {
this.bindAddress = bindAddress;
this.port = port;
this.invocationClass = invocationClass;
this.handlerCount = handlerCount;
this.socketSendBufferSize = 0;
this.maxQueueSize = handlerCount * MAX_QUEUE_SIZE_PER_HANDLER;
this.callQueue = new LinkedBlockingQueue(maxQueueSize);
this.maxIdleTime = 2 * 1000;
this.maxConnectionsToNuke = 10;
this.thresholdIdleConnections = 4000;
// Start the listener here and let it bind to the port
listener = new Listener();
this.port = listener.getAddress().getPort();
this.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, IOReadableWritable 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) {
if (rv == null) {
out.writeBoolean(false);
} else {
out.writeBoolean(true);
StringRecord.writeString(out, rv.getClass().getName());
rv.write(out);
}
} else {
StringRecord.writeString(out, errorClass);
StringRecord.writeString(out, error);
}
call.setResponse(ByteBuffer.wrap(response.toByteArray()));
}
/** 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() throws IOException {
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.debug("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 until shut down of handlers is complete
if (this.handlers != null) {
while (true) {
int i = 0;
for (; i < this.handlerCount; i++) {
if (this.handlers[i] != null) {
if (!this.handlers[i].isShutDown()) {
break;
}
}
}
if (i < this.handlerCount) {
try {
wait(100);
} catch (InterruptedException e) {
break;
}
} else {
// exit while loop
break;
}
}
}
// Wait until shut down of responder is complete
while (!this.responder.isShutDown()) {
try {
wait(100);
} catch (InterruptedException e) {
break;
}
}
// Wait until shut down of listener is complete
while (!this.listener.isShutDown()) {
try {
wait(100);
} catch (InterruptedException e) {
break;
}
}
}
/**
* 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. */
public abstract IOReadableWritable call(Class protocol, IOReadableWritable param, long receiveTime)
throws IOException;
/**
* 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 static int channelWrite(WritableByteChannel channel, ByteBuffer buffer) throws IOException {
return (buffer.remaining() <= NIO_BUFFER_LIMIT) ? channel.write(buffer) : channelIO(null, channel, buffer);
}
/**
* 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 static int channelRead(ReadableByteChannel channel, ByteBuffer buffer) throws IOException {
return (buffer.remaining() <= NIO_BUFFER_LIMIT) ? channel.read(buffer) : channelIO(channel, null, buffer);
}
/**
* 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;
}
public static T newInstance(Class theClass) {
T result;
Constructor meth = null;
try {
meth = theClass.getDeclaredConstructor(EMPTY_ARRAY);
meth.setAccessible(true);
result = meth.newInstance();
} catch (Exception e) {
throw new RuntimeException(e);
}
return result;
}
}
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