Java tutorial
/* * Copyright (c) 2011-2013 The original author or authors * ------------------------------------------------------ * All rights reserved. This program and the accompanying materials * are made available under the terms of the Eclipse Public License v1.0 * and Apache License v2.0 which accompanies this distribution. * * The Eclipse Public License is available at * http://www.eclipse.org/legal/epl-v10.html * * The Apache License v2.0 is available at * http://www.opensource.org/licenses/apache2.0.php * * You may elect to redistribute this code under either of these licenses. */ package io.vertx.core.impl.resolver; import io.netty.channel.ChannelFactory; import io.netty.channel.EventLoop; import io.netty.channel.socket.DatagramChannel; import io.netty.channel.socket.nio.NioDatagramChannel; import io.netty.resolver.AddressResolverGroup; import io.netty.resolver.HostsFileParser; import io.netty.resolver.NameResolver; import io.netty.resolver.dns.DnsAddressResolverGroup; import io.netty.resolver.dns.DnsNameResolverBuilder; import io.netty.resolver.dns.DnsServerAddressStream; import io.netty.resolver.dns.DnsServerAddresses; import io.netty.util.NetUtil; import io.netty.util.concurrent.EventExecutor; import io.vertx.core.Context; import io.vertx.core.Handler; import io.vertx.core.Vertx; import io.vertx.core.VertxException; import io.vertx.core.dns.AddressResolverOptions; import io.vertx.core.impl.AddressResolver; import io.vertx.core.impl.VertxImpl; import io.vertx.core.spi.resolver.ResolverProvider; import java.io.File; import java.io.IOException; import java.io.StringReader; import java.net.InetAddress; import java.net.InetSocketAddress; import java.net.UnknownHostException; import java.util.ArrayList; import java.util.Collections; import java.util.HashSet; import java.util.List; import java.util.Locale; import java.util.Map; import java.util.Set; import java.util.concurrent.atomic.AtomicInteger; /** * @author <a href="mailto:julien@julienviet.com">Julien Viet</a> */ public class DnsResolverProvider implements ResolverProvider { private final Vertx vertx; private final List<ResolverRegistration> resolvers = Collections.synchronizedList(new ArrayList<>()); private AddressResolverGroup<InetSocketAddress> resolverGroup; public DnsResolverProvider(VertxImpl vertx, AddressResolverOptions options) { List<String> dnsServers = options.getServers(); List<InetSocketAddress> serverList = new ArrayList<>(); if (dnsServers != null && dnsServers.size() > 0) { for (String dnsServer : dnsServers) { int sep = dnsServer.indexOf(':'); String ipAddress; int port; if (sep != -1) { ipAddress = dnsServer.substring(0, sep); port = Integer.parseInt(dnsServer.substring(sep + 1)); } else { ipAddress = dnsServer; port = 53; } try { serverList.add(new InetSocketAddress( InetAddress.getByAddress(NetUtil.createByteArrayFromIpAddressString(ipAddress)), port)); } catch (UnknownHostException e) { throw new VertxException(e); } } } else { DnsServerAddressStream stream = DnsServerAddresses.defaultAddresses().stream(); Set<InetSocketAddress> all = new HashSet<>(); while (true) { InetSocketAddress address = stream.next(); if (all.contains(address)) { break; } serverList.add(address); all.add(address); } } DnsServerAddresses nameServerAddresses = options.isRotateServers() ? DnsServerAddresses.rotational(serverList) : DnsServerAddresses.sequential(serverList); Map<String, InetAddress> entries; if (options.getHostsPath() != null) { File file = vertx.resolveFile(options.getHostsPath()).getAbsoluteFile(); try { if (!file.exists() || !file.isFile()) { throw new IOException(); } entries = HostsFileParser.parse(file); } catch (IOException e) { throw new VertxException("Cannot read hosts file " + file.getAbsolutePath()); } } else if (options.getHostsValue() != null) { try { entries = HostsFileParser.parse(new StringReader(options.getHostsValue().toString())); } catch (IOException e) { throw new VertxException("Cannot read hosts config ", e); } } else { entries = HostsFileParser.parseSilently(); } this.vertx = vertx; this.resolverGroup = new AddressResolverGroup<InetSocketAddress>() { @Override protected io.netty.resolver.AddressResolver<InetSocketAddress> newResolver(EventExecutor executor) throws Exception { DnsAddressResolverGroup group = new DnsAddressResolverGroup(NioDatagramChannel.class, nameServerAddresses) { @Override protected NameResolver<InetAddress> newNameResolver(EventLoop eventLoop, ChannelFactory<? extends DatagramChannel> channelFactory, DnsServerAddresses nameServerAddresses) throws Exception { DnsNameResolverBuilder builder = new DnsNameResolverBuilder((EventLoop) executor); builder.hostsFileEntriesResolver(inetHost -> { InetAddress addr = entries.get(inetHost); if (addr == null) { addr = entries.get(inetHost.toLowerCase(Locale.ENGLISH)); } return addr; }); builder.channelType(NioDatagramChannel.class); builder.nameServerAddresses(nameServerAddresses); builder.optResourceEnabled(options.isOptResourceEnabled()); builder.ttl(options.getCacheMinTimeToLive(), options.getCacheMaxTimeToLive()); builder.negativeTtl(options.getCacheNegativeTimeToLive()); builder.queryTimeoutMillis(options.getQueryTimeout()); builder.maxQueriesPerResolve(options.getMaxQueries()); builder.recursionDesired(options.getRdFlag()); if (options.getSearchDomains() != null) { builder.searchDomains(options.getSearchDomains()); int ndots = options.getNdots(); if (ndots == -1) { ndots = AddressResolver.DEFAULT_NDOTS_RESOLV_OPTION; } builder.ndots(ndots); } return builder.build(); } }; io.netty.resolver.AddressResolver<InetSocketAddress> resolver = group.getResolver(executor); resolvers.add(new ResolverRegistration(resolver, (EventLoop) executor)); return resolver; } }; } private static class ResolverRegistration { private final io.netty.resolver.AddressResolver<InetSocketAddress> resolver; private final EventLoop executor; ResolverRegistration(io.netty.resolver.AddressResolver<InetSocketAddress> resolver, EventLoop executor) { this.resolver = resolver; this.executor = executor; } } @Override public AddressResolverGroup<InetSocketAddress> resolver(AddressResolverOptions options) { return resolverGroup; } @Override public void close(Handler<Void> doneHandler) { Context context = vertx.getOrCreateContext(); ResolverRegistration[] registrations = this.resolvers .toArray(new ResolverRegistration[this.resolvers.size()]); if (registrations.length == 0) { context.runOnContext(doneHandler); return; } AtomicInteger count = new AtomicInteger(registrations.length); for (ResolverRegistration registration : registrations) { Runnable task = () -> { registration.resolver.close(); if (count.decrementAndGet() == 0) { context.runOnContext(doneHandler); } }; if (registration.executor.inEventLoop()) { task.run(); } else { registration.executor.execute(task); } } } }