/* Copyright 2011, 2012 predic8 GmbH, www.predic8.com
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. */
package com.predic8.membrane.core.transport.http;
import java.io.IOException;
import java.net.UnknownHostException;
import java.util.ArrayList;
import java.util.Collections;
import java.util.HashMap;
import java.util.Map;
import java.util.Timer;
import java.util.TimerTask;
import java.util.concurrent.atomic.AtomicInteger;
import com.predic8.membrane.core.transport.http.client.ProxyConfiguration;
import com.predic8.membrane.core.transport.ssl.SSLContext;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import com.google.common.base.Objects;
import com.predic8.membrane.core.transport.ssl.SSLProvider;
import javax.annotation.Nullable;
/**
* Pools TCP/IP connections, holding them open for a configurable number of milliseconds.
*
* With keep-alive use as follows:
* <code>
* Connection connection = connectionManager.getConnection(...);
* try {
* ...
* } finally {
* connection.release();
* }
* </code>
*
* Without keep-alive replace {@link Connection#release()} by {@link Connection#close()}.
*
* Note that you should call {@link Connection#release()} exactly once, or alternatively
* {@link Connection#close()} at least once.
*/
public class ConnectionManager {
private static Logger log = LoggerFactory.getLogger(ConnectionManager.class.getName());
private final long keepAliveTimeout;
private final long autoCloseInterval;
private static class ConnectionKey {
// SSLProvider and ProxyConfiguration do not override equals() or hashCode(), but this is OK, as only a few will exist and are used read-only
public final String host;
public final int port;
@Nullable private SSLProvider sslProvider;
@Nullable public String serverName;
@Nullable public ProxyConfiguration proxy;
public ConnectionKey(String host, int port, SSLProvider sslProvider, String serverName, ProxyConfiguration proxy) {
this.host = host;
this.port = port;
this.sslProvider = sslProvider;
this.serverName = serverName;
this.proxy = proxy;
}
@Override
public int hashCode() {
return Objects.hashCode(host, port, sslProvider, serverName, proxy);
}
@Override
public boolean equals(Object obj) {
if (!(obj instanceof ConnectionKey) || obj == null)
return false;
ConnectionKey other = (ConnectionKey)obj;
return host.equals(other.host)
&& port == other.port
&& Objects.equal(sslProvider,other.sslProvider)
&& Objects.equal(serverName, other.serverName)
&& Objects.equal(proxy,other.proxy);
}
@Override
public String toString() {
return host + ":" + port + (sslProvider != null ? " with SSL" : "") + (proxy != null ? " via proxy" : "");
}
}
private static class OldConnection {
public final Connection connection;
public final long deathTime;
public OldConnection(Connection connection, long defaultKeepAliveTimeout) {
this.connection = connection;
long lastUse = connection.getLastUse();
if (lastUse == 0)
lastUse = System.currentTimeMillis();
long delta = connection.getTimeout();
if (delta == 0)
delta = defaultKeepAliveTimeout;
if (delta > 400)
delta -= 400; // slippage
else
delta = 0;
if (connection.getCompletedExchanges() >= connection.getMaxExchanges())
delta = 0; // let the background closer do its job
this.deathTime = lastUse + delta;
}
}
private AtomicInteger numberInPool = new AtomicInteger();
private HashMap<ConnectionKey, ArrayList<OldConnection>> availableConnections =
new HashMap<ConnectionManager.ConnectionKey, ArrayList<OldConnection>>(); // guarded by this
private Timer timer;
private volatile boolean shutdownWhenDone = false;
public ConnectionManager(long keepAliveTimeout) {
this.keepAliveTimeout = keepAliveTimeout;
this.autoCloseInterval = keepAliveTimeout * 2;
timer = new Timer("Connection Closer", true);
timer.schedule(new TimerTask() {
@Override
public void run() {
if (closeOldConnections() == 0 && shutdownWhenDone)
timer.cancel();
}
}, autoCloseInterval, autoCloseInterval);
}
public Connection getConnection(String host, int port, String localHost, SSLProvider sslProvider, int connectTimeout, @Nullable String sniServerName,
@Nullable ProxyConfiguration proxy, @Nullable SSLContext proxySSLContext) throws UnknownHostException, IOException {
log.debug("connection requested for " + host + ":" + port + (proxy != null ? " via " + proxy.getHost() + ":" + proxy.getPort() : ""));
log.debug("Number of connections in pool: " + numberInPool.get());
String cacheHost = host;
int cachePort = port;
if (proxy != null && sslProvider == null) {
// if a proxy is used, but no SSLProvider, the host:port do not have to be included in the ConnectionKey,
// as this simply caches the connection to the proxy
cacheHost = "";
cachePort = 0;
}
ConnectionKey key = new ConnectionKey(cacheHost, cachePort, sslProvider, sniServerName, proxy);
long now = System.currentTimeMillis();
synchronized(this) {
ArrayList<OldConnection> l = availableConnections.get(key);
if (l != null) {
int i = l.size() - 1;
while(i >= 0) {
OldConnection c = l.get(i);
if (c.deathTime > now) {
l.remove(i);
return c.connection;
}
Collections.swap(l, 0, i);
i--;
}
}
}
Connection result = Connection.open(host, port, localHost, sslProvider, this, connectTimeout,sniServerName,proxy,proxySSLContext);
numberInPool.incrementAndGet();
return result;
}
public Connection getConnection(String host, int port, String localHost, SSLProvider sslProvider, int connectTimeout) throws UnknownHostException, IOException {
return getConnection(host,port,localHost,sslProvider,connectTimeout,null,null,null);
}
public void releaseConnection(Connection connection) {
if (connection == null)
return;
if (connection.isClosed()) {
numberInPool.decrementAndGet();
return;
}
ConnectionKey key = new ConnectionKey(connection.getHost(), connection.socket.getPort(), connection.getSslProvider(), connection.getSniServerName(),connection.getProxyConfiguration());
OldConnection o = new OldConnection(connection, keepAliveTimeout);
ArrayList<OldConnection> l;
synchronized(this) {
l = availableConnections.get(key);
if (l == null) {
l = new ArrayList<OldConnection>();
availableConnections.put(key, l);
}
l.add(o);
}
}
private int closeOldConnections() {
ArrayList<ConnectionKey> toRemove = new ArrayList<ConnectionKey>();
ArrayList<Connection> toClose = new ArrayList<Connection>();
long now = System.currentTimeMillis();
log.trace("closing old connections");
int closed = 0, remaining;
synchronized(this) {
// close connections after their timeout
for (Map.Entry<ConnectionKey, ArrayList<OldConnection>> e : availableConnections.entrySet()) {
ArrayList<OldConnection> l = e.getValue();
for (int i = 0; i < l.size(); i++) {
OldConnection o = l.get(i);
if (o.deathTime < now) {
// replace [i] by [last]
if (i == l.size() - 1)
l.remove(i);
else
l.set(i, l.remove(l.size() - 1));
--i;
closed++;
toClose.add(o.connection);
}
}
if (l.isEmpty())
toRemove.add(e.getKey());
}
for (ConnectionKey remove : toRemove)
availableConnections.remove(remove);
remaining = availableConnections.size();
}
for (Connection c : toClose) {
try {
c.close();
} catch (Exception e) {
// do nothing
}
}
if (closed != 0)
log.debug("closed " + closed + " connections");
return remaining;
}
public void shutdownWhenDone() {
shutdownWhenDone = true;
}
public int getNumberInPool() {
return numberInPool.get();
}
@Override
public String toString() {
StringBuilder sb = new StringBuilder();
sb.append("Number in pool: " + numberInPool.get() + "\n");
synchronized(this) {
for (Map.Entry<ConnectionKey, ArrayList<OldConnection>> e : availableConnections.entrySet()) {
sb.append("To " + e.getKey() + ": " + e.getValue().size() + "\n");
}
}
return sb.toString();
}
}