org.apache.zookeeper.server.NIOServerCnxnFactory Maven / Gradle / Ivy
/*
* 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.zookeeper.server;
import java.io.IOException;
import java.io.PrintWriter;
import java.net.InetAddress;
import java.net.InetSocketAddress;
import java.net.SocketException;
import java.nio.ByteBuffer;
import java.nio.channels.SelectionKey;
import java.nio.channels.Selector;
import java.nio.channels.ServerSocketChannel;
import java.nio.channels.SocketChannel;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.HashSet;
import java.util.Iterator;
import java.util.Map;
import java.util.Queue;
import java.util.Set;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.LinkedBlockingQueue;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
* NIOServerCnxnFactory implements a multi-threaded ServerCnxnFactory using
* NIO non-blocking socket calls. Communication between threads is handled via
* queues.
*
* - 1 accept thread, which accepts new connections and assigns to a
* selector thread
* - 1-N selector threads, each of which selects on 1/N of the connections.
* The reason the factory supports more than one selector thread is that
* with large numbers of connections, select() itself can become a
* performance bottleneck.
* - 0-M socket I/O worker threads, which perform basic socket reads and
* writes. If configured with 0 worker threads, the selector threads
* do the socket I/O directly.
* - 1 connection expiration thread, which closes idle connections; this is
* necessary to expire connections on which no session is established.
*
* Typical (default) thread counts are: on a 32 core machine, 1 accept thread,
* 1 connection expiration thread, 4 selector threads, and 64 worker threads.
*/
public class NIOServerCnxnFactory extends ServerCnxnFactory {
private static final Logger LOG = LoggerFactory.getLogger(NIOServerCnxnFactory.class);
/** Default sessionless connection timeout in ms: 10000 (10s) */
public static final String ZOOKEEPER_NIO_SESSIONLESS_CNXN_TIMEOUT = "zookeeper.nio.sessionlessCnxnTimeout";
/**
* With 500 connections to an observer with watchers firing on each, is
* unable to exceed 1GigE rates with only 1 selector.
* Defaults to using 2 selector threads with 8 cores and 4 with 32 cores.
* Expressed as sqrt(numCores/2). Must have at least 1 selector thread.
*/
public static final String ZOOKEEPER_NIO_NUM_SELECTOR_THREADS = "zookeeper.nio.numSelectorThreads";
/** Default: 2 * numCores */
public static final String ZOOKEEPER_NIO_NUM_WORKER_THREADS = "zookeeper.nio.numWorkerThreads";
/** Default: 64kB */
public static final String ZOOKEEPER_NIO_DIRECT_BUFFER_BYTES = "zookeeper.nio.directBufferBytes";
/** Default worker pool shutdown timeout in ms: 5000 (5s) */
public static final String ZOOKEEPER_NIO_SHUTDOWN_TIMEOUT = "zookeeper.nio.shutdownTimeout";
static {
Thread.setDefaultUncaughtExceptionHandler(new Thread.UncaughtExceptionHandler() {
public void uncaughtException(Thread t, Throwable e) {
LOG.error("Thread {} died", t, e);
}
});
/**
* this is to avoid the jvm bug:
* NullPointerException in Selector.open()
* http://bugs.sun.com/view_bug.do?bug_id=6427854
*/
try {
Selector.open().close();
} catch (IOException ie) {
LOG.error("Selector failed to open", ie);
}
/**
* Value of 0 disables use of direct buffers and instead uses
* gathered write call.
*
* Default to using 64k direct buffers.
*/
directBufferBytes = Integer.getInteger(ZOOKEEPER_NIO_DIRECT_BUFFER_BYTES, 64 * 1024);
}
/**
* AbstractSelectThread is an abstract base class containing a few bits
* of code shared by the AcceptThread (which selects on the listen socket)
* and SelectorThread (which selects on client connections) classes.
*/
private abstract class AbstractSelectThread extends ZooKeeperThread {
protected final Selector selector;
public AbstractSelectThread(String name) throws IOException {
super(name);
// Allows the JVM to shutdown even if this thread is still running.
setDaemon(true);
this.selector = Selector.open();
}
public void wakeupSelector() {
selector.wakeup();
}
/**
* Close the selector. This should be called when the thread is about to
* exit and no operation is going to be performed on the Selector or
* SelectionKey
*/
protected void closeSelector() {
try {
selector.close();
} catch (IOException e) {
LOG.warn("ignored exception during selector close.", e);
}
}
protected void cleanupSelectionKey(SelectionKey key) {
if (key != null) {
try {
key.cancel();
} catch (Exception ex) {
LOG.debug("ignoring exception during selectionkey cancel", ex);
}
}
}
protected void fastCloseSock(SocketChannel sc) {
if (sc != null) {
try {
// Hard close immediately, discarding buffers
sc.socket().setSoLinger(true, 0);
} catch (SocketException e) {
LOG.warn("Unable to set socket linger to 0, socket close may stall in CLOSE_WAIT", e);
}
NIOServerCnxn.closeSock(sc);
}
}
}
/**
* There is a single AcceptThread which accepts new connections and assigns
* them to a SelectorThread using a simple round-robin scheme to spread
* them across the SelectorThreads. It enforces maximum number of
* connections per IP and attempts to cope with running out of file
* descriptors by briefly sleeping before retrying.
*/
private class AcceptThread extends AbstractSelectThread {
private final ServerSocketChannel acceptSocket;
private final SelectionKey acceptKey;
private final RateLogger acceptErrorLogger = new RateLogger(LOG);
private final Collection selectorThreads;
private Iterator selectorIterator;
private volatile boolean reconfiguring = false;
public AcceptThread(ServerSocketChannel ss, InetSocketAddress addr, Set selectorThreads) throws IOException {
super("NIOServerCxnFactory.AcceptThread:" + addr);
this.acceptSocket = ss;
this.acceptKey = acceptSocket.register(selector, SelectionKey.OP_ACCEPT);
this.selectorThreads = Collections.unmodifiableList(new ArrayList(selectorThreads));
selectorIterator = this.selectorThreads.iterator();
}
public void run() {
try {
while (!stopped && !acceptSocket.socket().isClosed()) {
try {
select();
} catch (RuntimeException e) {
LOG.warn("Ignoring unexpected runtime exception", e);
} catch (Exception e) {
LOG.warn("Ignoring unexpected exception", e);
}
}
} finally {
closeSelector();
// This will wake up the selector threads, and tell the
// worker thread pool to begin shutdown.
if (!reconfiguring) {
NIOServerCnxnFactory.this.stop();
}
LOG.info("accept thread exitted run method");
}
}
public void setReconfiguring() {
reconfiguring = true;
}
private void select() {
try {
selector.select();
Iterator selectedKeys = selector.selectedKeys().iterator();
while (!stopped && selectedKeys.hasNext()) {
SelectionKey key = selectedKeys.next();
selectedKeys.remove();
if (!key.isValid()) {
continue;
}
if (key.isAcceptable()) {
if (!doAccept()) {
// If unable to pull a new connection off the accept
// queue, pause accepting to give us time to free
// up file descriptors and so the accept thread
// doesn't spin in a tight loop.
pauseAccept(10);
}
} else {
LOG.warn("Unexpected ops in accept select {}", key.readyOps());
}
}
} catch (IOException e) {
LOG.warn("Ignoring IOException while selecting", e);
}
}
/**
* Mask off the listen socket interest ops and use select() to sleep
* so that other threads can wake us up by calling wakeup() on the
* selector.
*/
private void pauseAccept(long millisecs) {
acceptKey.interestOps(0);
try {
selector.select(millisecs);
} catch (IOException e) {
// ignore
} finally {
acceptKey.interestOps(SelectionKey.OP_ACCEPT);
}
}
/**
* Accept new socket connections. Enforces maximum number of connections
* per client IP address. Round-robin assigns to selector thread for
* handling. Returns whether pulled a connection off the accept queue
* or not. If encounters an error attempts to fast close the socket.
*
* @return whether was able to accept a connection or not
*/
private boolean doAccept() {
boolean accepted = false;
SocketChannel sc = null;
try {
sc = acceptSocket.accept();
accepted = true;
if (limitTotalNumberOfCnxns()) {
throw new IOException("Too many connections max allowed is " + maxCnxns);
}
InetAddress ia = sc.socket().getInetAddress();
int cnxncount = getClientCnxnCount(ia);
if (maxClientCnxns > 0 && cnxncount >= maxClientCnxns) {
throw new IOException("Too many connections from " + ia + " - max is " + maxClientCnxns);
}
LOG.debug("Accepted socket connection from {}", sc.socket().getRemoteSocketAddress());
sc.configureBlocking(false);
// Round-robin assign this connection to a selector thread
if (!selectorIterator.hasNext()) {
selectorIterator = selectorThreads.iterator();
}
SelectorThread selectorThread = selectorIterator.next();
if (!selectorThread.addAcceptedConnection(sc)) {
throw new IOException("Unable to add connection to selector queue"
+ (stopped ? " (shutdown in progress)" : ""));
}
acceptErrorLogger.flush();
} catch (IOException e) {
// accept, maxClientCnxns, configureBlocking
ServerMetrics.getMetrics().CONNECTION_REJECTED.add(1);
acceptErrorLogger.rateLimitLog("Error accepting new connection: " + e.getMessage());
fastCloseSock(sc);
}
return accepted;
}
}
/**
* The SelectorThread receives newly accepted connections from the
* AcceptThread and is responsible for selecting for I/O readiness
* across the connections. This thread is the only thread that performs
* any non-threadsafe or potentially blocking calls on the selector
* (registering new connections and reading/writing interest ops).
*
* Assignment of a connection to a SelectorThread is permanent and only
* one SelectorThread will ever interact with the connection. There are
* 1-N SelectorThreads, with connections evenly apportioned between the
* SelectorThreads.
*
* If there is a worker thread pool, when a connection has I/O to perform
* the SelectorThread removes it from selection by clearing its interest
* ops and schedules the I/O for processing by a worker thread. When the
* work is complete, the connection is placed on the ready queue to have
* its interest ops restored and resume selection.
*
* If there is no worker thread pool, the SelectorThread performs the I/O
* directly.
*/
class SelectorThread extends AbstractSelectThread {
private final int id;
private final Queue acceptedQueue;
private final Queue updateQueue;
public SelectorThread(int id) throws IOException {
super("NIOServerCxnFactory.SelectorThread-" + id);
this.id = id;
acceptedQueue = new LinkedBlockingQueue();
updateQueue = new LinkedBlockingQueue();
}
/**
* Place new accepted connection onto a queue for adding. Do this
* so only the selector thread modifies what keys are registered
* with the selector.
*/
public boolean addAcceptedConnection(SocketChannel accepted) {
if (stopped || !acceptedQueue.offer(accepted)) {
return false;
}
wakeupSelector();
return true;
}
/**
* Place interest op update requests onto a queue so that only the
* selector thread modifies interest ops, because interest ops
* reads/sets are potentially blocking operations if other select
* operations are happening.
*/
public boolean addInterestOpsUpdateRequest(SelectionKey sk) {
if (stopped || !updateQueue.offer(sk)) {
return false;
}
wakeupSelector();
return true;
}
/**
* The main loop for the thread selects() on the connections and
* dispatches ready I/O work requests, then registers all pending
* newly accepted connections and updates any interest ops on the
* queue.
*/
public void run() {
try {
while (!stopped) {
try {
select();
processAcceptedConnections();
processInterestOpsUpdateRequests();
} catch (RuntimeException e) {
LOG.warn("Ignoring unexpected runtime exception", e);
} catch (Exception e) {
LOG.warn("Ignoring unexpected exception", e);
}
}
// Close connections still pending on the selector. Any others
// with in-flight work, let drain out of the work queue.
for (SelectionKey key : selector.keys()) {
NIOServerCnxn cnxn = (NIOServerCnxn) key.attachment();
if (cnxn.isSelectable()) {
cnxn.close(ServerCnxn.DisconnectReason.SERVER_SHUTDOWN);
}
cleanupSelectionKey(key);
}
SocketChannel accepted;
while ((accepted = acceptedQueue.poll()) != null) {
fastCloseSock(accepted);
}
updateQueue.clear();
} finally {
closeSelector();
// This will wake up the accept thread and the other selector
// threads, and tell the worker thread pool to begin shutdown.
NIOServerCnxnFactory.this.stop();
LOG.info("selector thread exitted run method");
}
}
private void select() {
try {
selector.select();
Set selected = selector.selectedKeys();
ArrayList selectedList = new ArrayList(selected);
Collections.shuffle(selectedList);
Iterator selectedKeys = selectedList.iterator();
while (!stopped && selectedKeys.hasNext()) {
SelectionKey key = selectedKeys.next();
selected.remove(key);
if (!key.isValid()) {
cleanupSelectionKey(key);
continue;
}
if (key.isReadable() || key.isWritable()) {
handleIO(key);
} else {
LOG.warn("Unexpected ops in select {}", key.readyOps());
}
}
} catch (IOException e) {
LOG.warn("Ignoring IOException while selecting", e);
}
}
/**
* Schedule I/O for processing on the connection associated with
* the given SelectionKey. If a worker thread pool is not being used,
* I/O is run directly by this thread.
*/
private void handleIO(SelectionKey key) {
IOWorkRequest workRequest = new IOWorkRequest(this, key);
NIOServerCnxn cnxn = (NIOServerCnxn) key.attachment();
// Stop selecting this key while processing on its
// connection
cnxn.disableSelectable();
key.interestOps(0);
touchCnxn(cnxn);
workerPool.schedule(workRequest);
}
/**
* Iterate over the queue of accepted connections that have been
* assigned to this thread but not yet placed on the selector.
*/
private void processAcceptedConnections() {
SocketChannel accepted;
while (!stopped && (accepted = acceptedQueue.poll()) != null) {
SelectionKey key = null;
try {
key = accepted.register(selector, SelectionKey.OP_READ);
NIOServerCnxn cnxn = createConnection(accepted, key, this);
key.attach(cnxn);
addCnxn(cnxn);
} catch (IOException e) {
// register, createConnection
cleanupSelectionKey(key);
fastCloseSock(accepted);
}
}
}
/**
* Iterate over the queue of connections ready to resume selection,
* and restore their interest ops selection mask.
*/
private void processInterestOpsUpdateRequests() {
SelectionKey key;
while (!stopped && (key = updateQueue.poll()) != null) {
if (!key.isValid()) {
cleanupSelectionKey(key);
}
NIOServerCnxn cnxn = (NIOServerCnxn) key.attachment();
if (cnxn.isSelectable()) {
key.interestOps(cnxn.getInterestOps());
}
}
}
}
/**
* IOWorkRequest is a small wrapper class to allow doIO() calls to be
* run on a connection using a WorkerService.
*/
private class IOWorkRequest extends WorkerService.WorkRequest {
private final SelectorThread selectorThread;
private final SelectionKey key;
private final NIOServerCnxn cnxn;
IOWorkRequest(SelectorThread selectorThread, SelectionKey key) {
this.selectorThread = selectorThread;
this.key = key;
this.cnxn = (NIOServerCnxn) key.attachment();
}
public void doWork() throws InterruptedException {
if (!key.isValid()) {
selectorThread.cleanupSelectionKey(key);
return;
}
if (key.isReadable() || key.isWritable()) {
cnxn.doIO(key);
// Check if we shutdown or doIO() closed this connection
if (stopped) {
cnxn.close(ServerCnxn.DisconnectReason.SERVER_SHUTDOWN);
return;
}
if (!key.isValid()) {
selectorThread.cleanupSelectionKey(key);
return;
}
touchCnxn(cnxn);
}
// Mark this connection as once again ready for selection
cnxn.enableSelectable();
// Push an update request on the queue to resume selecting
// on the current set of interest ops, which may have changed
// as a result of the I/O operations we just performed.
if (!selectorThread.addInterestOpsUpdateRequest(key)) {
cnxn.close(ServerCnxn.DisconnectReason.CONNECTION_MODE_CHANGED);
}
}
@Override
public void cleanup() {
cnxn.close(ServerCnxn.DisconnectReason.CLEAN_UP);
}
}
/**
* This thread is responsible for closing stale connections so that
* connections on which no session is established are properly expired.
*/
private class ConnectionExpirerThread extends ZooKeeperThread {
ConnectionExpirerThread() {
super("ConnnectionExpirer");
}
public void run() {
try {
while (!stopped) {
long waitTime = cnxnExpiryQueue.getWaitTime();
if (waitTime > 0) {
Thread.sleep(waitTime);
continue;
}
for (NIOServerCnxn conn : cnxnExpiryQueue.poll()) {
ServerMetrics.getMetrics().SESSIONLESS_CONNECTIONS_EXPIRED.add(1);
conn.close(ServerCnxn.DisconnectReason.CONNECTION_EXPIRED);
}
}
} catch (InterruptedException e) {
LOG.info("ConnnectionExpirerThread interrupted");
}
}
}
ServerSocketChannel ss;
/**
* We use this buffer to do efficient socket I/O. Because I/O is handled
* by the worker threads (or the selector threads directly, if no worker
* thread pool is created), we can create a fixed set of these to be
* shared by connections.
*/
private static final ThreadLocal directBuffer = new ThreadLocal() {
@Override
protected ByteBuffer initialValue() {
return ByteBuffer.allocateDirect(directBufferBytes);
}
};
public static ByteBuffer getDirectBuffer() {
return directBufferBytes > 0 ? directBuffer.get() : null;
}
// ipMap is used to limit connections per IP
private final ConcurrentHashMap> ipMap = new ConcurrentHashMap>();
protected int maxClientCnxns = 60;
int listenBacklog = -1;
int sessionlessCnxnTimeout;
private ExpiryQueue cnxnExpiryQueue;
protected WorkerService workerPool;
private static int directBufferBytes;
private int numSelectorThreads;
private int numWorkerThreads;
private long workerShutdownTimeoutMS;
/**
* Construct a new server connection factory which will accept an unlimited number
* of concurrent connections from each client (up to the file descriptor
* limits of the operating system). startup(zks) must be called subsequently.
*/
public NIOServerCnxnFactory() {
}
private volatile boolean stopped = true;
private ConnectionExpirerThread expirerThread;
private AcceptThread acceptThread;
private final Set selectorThreads = new HashSet();
@Override
public void configure(InetSocketAddress addr, int maxcc, int backlog, boolean secure) throws IOException {
if (secure) {
throw new UnsupportedOperationException("SSL isn't supported in NIOServerCnxn");
}
configureSaslLogin();
maxClientCnxns = maxcc;
initMaxCnxns();
sessionlessCnxnTimeout = Integer.getInteger(ZOOKEEPER_NIO_SESSIONLESS_CNXN_TIMEOUT, 10000);
// We also use the sessionlessCnxnTimeout as expiring interval for
// cnxnExpiryQueue. These don't need to be the same, but the expiring
// interval passed into the ExpiryQueue() constructor below should be
// less than or equal to the timeout.
cnxnExpiryQueue = new ExpiryQueue(sessionlessCnxnTimeout);
expirerThread = new ConnectionExpirerThread();
int numCores = Runtime.getRuntime().availableProcessors();
// 32 cores sweet spot seems to be 4 selector threads
numSelectorThreads = Integer.getInteger(
ZOOKEEPER_NIO_NUM_SELECTOR_THREADS,
Math.max((int) Math.sqrt((float) numCores / 2), 1));
if (numSelectorThreads < 1) {
throw new IOException("numSelectorThreads must be at least 1");
}
numWorkerThreads = Integer.getInteger(ZOOKEEPER_NIO_NUM_WORKER_THREADS, 2 * numCores);
workerShutdownTimeoutMS = Long.getLong(ZOOKEEPER_NIO_SHUTDOWN_TIMEOUT, 5000);
String logMsg = "Configuring NIO connection handler with "
+ (sessionlessCnxnTimeout / 1000) + "s sessionless connection timeout, "
+ numSelectorThreads + " selector thread(s), "
+ (numWorkerThreads > 0 ? numWorkerThreads : "no") + " worker threads, and "
+ (directBufferBytes == 0 ? "gathered writes." : ("" + (directBufferBytes / 1024) + " kB direct buffers."));
LOG.info(logMsg);
for (int i = 0; i < numSelectorThreads; ++i) {
selectorThreads.add(new SelectorThread(i));
}
listenBacklog = backlog;
this.ss = ServerSocketChannel.open();
ss.socket().setReuseAddress(true);
LOG.info("binding to port {}", addr);
if (listenBacklog == -1) {
ss.socket().bind(addr);
} else {
ss.socket().bind(addr, listenBacklog);
}
ss.configureBlocking(false);
acceptThread = new AcceptThread(ss, addr, selectorThreads);
}
private void tryClose(ServerSocketChannel s) {
try {
s.close();
} catch (IOException sse) {
LOG.error("Error while closing server socket.", sse);
}
}
@Override
public void reconfigure(InetSocketAddress addr) {
ServerSocketChannel oldSS = ss;
try {
acceptThread.setReconfiguring();
tryClose(oldSS);
acceptThread.wakeupSelector();
try {
acceptThread.join();
} catch (InterruptedException e) {
LOG.error("Error joining old acceptThread when reconfiguring client port.", e);
Thread.currentThread().interrupt();
}
this.ss = ServerSocketChannel.open();
ss.socket().setReuseAddress(true);
LOG.info("binding to port {}", addr);
ss.socket().bind(addr);
ss.configureBlocking(false);
acceptThread = new AcceptThread(ss, addr, selectorThreads);
acceptThread.start();
} catch (IOException e) {
LOG.error("Error reconfiguring client port to {}", addr, e);
tryClose(oldSS);
}
}
/** {@inheritDoc} */
public int getMaxClientCnxnsPerHost() {
return maxClientCnxns;
}
/** {@inheritDoc} */
public void setMaxClientCnxnsPerHost(int max) {
maxClientCnxns = max;
}
/** {@inheritDoc} */
public int getSocketListenBacklog() {
return listenBacklog;
}
@Override
public void start() {
stopped = false;
if (workerPool == null) {
workerPool = new WorkerService("NIOWorker", numWorkerThreads, false);
}
for (SelectorThread thread : selectorThreads) {
if (thread.getState() == Thread.State.NEW) {
thread.start();
}
}
// ensure thread is started once and only once
if (acceptThread.getState() == Thread.State.NEW) {
acceptThread.start();
}
if (expirerThread.getState() == Thread.State.NEW) {
expirerThread.start();
}
}
@Override
public void startup(ZooKeeperServer zks, boolean startServer) throws IOException, InterruptedException {
start();
setZooKeeperServer(zks);
if (startServer) {
zks.startdata();
zks.startup();
}
}
@Override
public InetSocketAddress getLocalAddress() {
return (InetSocketAddress) ss.socket().getLocalSocketAddress();
}
@Override
public int getLocalPort() {
return ss.socket().getLocalPort();
}
/**
* De-registers the connection from the various mappings maintained
* by the factory.
*/
public boolean removeCnxn(NIOServerCnxn cnxn) {
// If the connection is not in the master list it's already been closed
if (!cnxns.remove(cnxn)) {
return false;
}
cnxnExpiryQueue.remove(cnxn);
removeCnxnFromSessionMap(cnxn);
InetAddress addr = cnxn.getSocketAddress();
if (addr != null) {
Set set = ipMap.get(addr);
if (set != null) {
set.remove(cnxn);
// Note that we make no effort here to remove empty mappings
// from ipMap.
}
}
// unregister from JMX
unregisterConnection(cnxn);
return true;
}
/**
* Add or update cnxn in our cnxnExpiryQueue
* @param cnxn
*/
public void touchCnxn(NIOServerCnxn cnxn) {
cnxnExpiryQueue.update(cnxn, cnxn.getSessionTimeout());
}
private void addCnxn(NIOServerCnxn cnxn) throws IOException {
InetAddress addr = cnxn.getSocketAddress();
if (addr == null) {
throw new IOException("Socket of " + cnxn + " has been closed");
}
Set set = ipMap.get(addr);
if (set == null) {
// in general we will see 1 connection from each
// host, setting the initial cap to 2 allows us
// to minimize mem usage in the common case
// of 1 entry -- we need to set the initial cap
// to 2 to avoid rehash when the first entry is added
// Construct a ConcurrentHashSet using a ConcurrentHashMap
set = Collections.newSetFromMap(new ConcurrentHashMap(2));
// Put the new set in the map, but only if another thread
// hasn't beaten us to it
Set existingSet = ipMap.putIfAbsent(addr, set);
if (existingSet != null) {
set = existingSet;
}
}
set.add(cnxn);
cnxns.add(cnxn);
touchCnxn(cnxn);
}
protected NIOServerCnxn createConnection(SocketChannel sock, SelectionKey sk, SelectorThread selectorThread) throws IOException {
return new NIOServerCnxn(zkServer, sock, sk, this, selectorThread);
}
private int getClientCnxnCount(InetAddress cl) {
Set s = ipMap.get(cl);
if (s == null) {
return 0;
}
return s.size();
}
/**
* clear all the connections in the selector
*
*/
@Override
@SuppressWarnings("unchecked")
public void closeAll(ServerCnxn.DisconnectReason reason) {
// clear all the connections on which we are selecting
for (ServerCnxn cnxn : cnxns) {
try {
// This will remove the cnxn from cnxns
cnxn.close(reason);
} catch (Exception e) {
LOG.warn(
"Ignoring exception closing cnxn session id 0x{}",
Long.toHexString(cnxn.getSessionId()),
e);
}
}
}
public void stop() {
stopped = true;
// Stop queuing connection attempts
try {
ss.close();
} catch (IOException e) {
LOG.warn("Error closing listen socket", e);
}
if (acceptThread != null) {
if (acceptThread.isAlive()) {
acceptThread.wakeupSelector();
} else {
acceptThread.closeSelector();
}
}
if (expirerThread != null) {
expirerThread.interrupt();
}
for (SelectorThread thread : selectorThreads) {
if (thread.isAlive()) {
thread.wakeupSelector();
} else {
thread.closeSelector();
}
}
if (workerPool != null) {
workerPool.stop();
}
}
public void shutdown() {
try {
// close listen socket and signal selector threads to stop
stop();
// wait for selector and worker threads to shutdown
join();
// close all open connections
closeAll(ServerCnxn.DisconnectReason.SERVER_SHUTDOWN);
if (login != null) {
login.shutdown();
}
} catch (InterruptedException e) {
LOG.warn("Ignoring interrupted exception during shutdown", e);
} catch (Exception e) {
LOG.warn("Ignoring unexpected exception during shutdown", e);
}
if (zkServer != null) {
zkServer.shutdown();
}
}
@Override
public void join() throws InterruptedException {
if (acceptThread != null) {
acceptThread.join();
}
for (SelectorThread thread : selectorThreads) {
thread.join();
}
if (workerPool != null) {
workerPool.join(workerShutdownTimeoutMS);
}
}
@Override
public Iterable getConnections() {
return cnxns;
}
public void dumpConnections(PrintWriter pwriter) {
pwriter.print("Connections ");
cnxnExpiryQueue.dump(pwriter);
}
@Override
public void resetAllConnectionStats() {
// No need to synchronize since cnxns is backed by a ConcurrentHashMap
for (ServerCnxn c : cnxns) {
c.resetStats();
}
}
@Override
public Iterable> getAllConnectionInfo(boolean brief) {
HashSet> info = new HashSet>();
// No need to synchronize since cnxns is backed by a ConcurrentHashMap
for (ServerCnxn c : cnxns) {
info.add(c.getConnectionInfo(brief));
}
return info;
}
}
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