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Safe shutdown of ThreadGroup for DnsClient

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This commit is contained in:
nathan 2016-02-29 02:42:40 +01:00
parent dfd9e2c69d
commit 04a9365351
1 changed files with 55 additions and 13 deletions
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68
Dorkbox-Network/src/dorkbox/network/DnsClient.java
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@ -15,6 +15,7 @@
*/
package dorkbox.network;
import dorkbox.network.connection.EndPoint;
import dorkbox.network.dns.decoder.DomainDecoder;
import dorkbox.network.dns.decoder.MailExchangerDecoder;
import dorkbox.network.dns.decoder.RecordDecoder;
@ -60,8 +61,10 @@ import java.util.Arrays;
import java.util.Collection;
import java.util.Collections;
import java.util.HashMap;
import java.util.LinkedList;
import java.util.List;
import java.util.Map;
import java.util.concurrent.TimeUnit;
/**
* for now, we only support ipv4
@ -69,6 +72,7 @@ import java.util.Map;
@SuppressWarnings("unused")
public
class DnsClient {
static {
try {
// doesn't work in eclipse.
@ -118,6 +122,9 @@ class DnsClient {
private final DnsNameResolver resolver;
private final Map<DnsRecordType, RecordDecoder<?>> customDecoders = new HashMap<DnsRecordType, RecordDecoder<?>>();
private ThreadGroup threadGroup;
public static final String THREAD_NAME = "DnsClient";
private EventLoopGroup eventLoopGroup;
/**
* Creates a new DNS client, using the provided server (default port 53) for DNS query resolution, with a cache that will obey the TTL of the response
@ -161,38 +168,34 @@ class DnsClient {
*/
public
DnsClient(Collection<InetSocketAddress> nameServerAddresses, int minTtl, int maxTtl) {
EventLoopGroup group;
Class<? extends DatagramChannel> channelType;
final String threadName = "DnsClient";
// setup the thread group to easily ID what the following threads belong to (and their spawned threads...)
SecurityManager s = System.getSecurityManager();
ThreadGroup nettyGroup = new ThreadGroup(s != null
? s.getThreadGroup()
: Thread.currentThread()
.getThreadGroup(), threadName);
nettyGroup.setDaemon(true);
threadGroup = new ThreadGroup(s != null
? s.getThreadGroup()
: Thread.currentThread()
.getThreadGroup(), THREAD_NAME);
threadGroup.setDaemon(true);
if (PlatformDependent.isAndroid()) {
// android ONLY supports OIO (not NIO)
group = new OioEventLoopGroup(1, new NamedThreadFactory(threadName + "-UDP", nettyGroup));
eventLoopGroup = new OioEventLoopGroup(1, new NamedThreadFactory(THREAD_NAME + "-UDP", threadGroup));
channelType = OioDatagramChannel.class;
}
else if (OS.isLinux()) {
// JNI network stack is MUCH faster (but only on linux)
group = new EpollEventLoopGroup(1, new NamedThreadFactory(threadName + "-UDP", nettyGroup));
eventLoopGroup = new EpollEventLoopGroup(1, new NamedThreadFactory(THREAD_NAME + "-UDP", threadGroup));
channelType = EpollDatagramChannel.class;
}
else {
group = new NioEventLoopGroup(1, new NamedThreadFactory(threadName + "-UDP", nettyGroup));
eventLoopGroup = new NioEventLoopGroup(1, new NamedThreadFactory(THREAD_NAME + "-UDP", threadGroup));
channelType = NioDatagramChannel.class;
}
DnsNameResolverBuilder builder = new DnsNameResolverBuilder(group.next());
DnsNameResolverBuilder builder = new DnsNameResolverBuilder(eventLoopGroup.next());
builder.channelFactory(new ReflectiveChannelFactory<DatagramChannel>(channelType))
.channelType(channelType)
.localAddress(null)
.ttl(minTtl, maxTtl)
.resolvedAddressTypes(InternetProtocolFamily.IPv4) // for now, we only support ipv4
.nameServerAddresses(DnsServerAddresses.sequential(nameServerAddresses));
@ -335,6 +338,45 @@ class DnsClient {
void stop() {
reset();
resolver.close();
// we also want to stop the thread group (but NOT in our current thread!)
if (Thread.currentThread()
.getThreadGroup()
.getName()
.equals(THREAD_NAME)) {
Thread thread = new Thread(new Runnable() {
@Override
public
void run() {
DnsClient.this.stopInThread();
}
});
thread.setDaemon(false);
thread.setName("DnsClient Shutdown");
thread.start();
}
else {
stopInThread();
}
}
private
void stopInThread() {
// Sometimes there might be "lingering" connections (ie, halfway though registration) that need to be closed.
long maxShutdownWaitTimeInMilliSeconds = EndPoint.maxShutdownWaitTimeInMilliSeconds;
// we want to WAIT until after the event executors have completed shutting down.
List<Future<?>> shutdownThreadList = new LinkedList<Future<?>>();
// now wait it them to finish!
// It can take a few seconds to shut down the executor. This will affect unit testing, where connections are quickly created/stopped
eventLoopGroup.shutdownGracefully(maxShutdownWaitTimeInMilliSeconds, maxShutdownWaitTimeInMilliSeconds * 4, TimeUnit.MILLISECONDS)
.syncUninterruptibly();
threadGroup.interrupt();
}
public