Motivation: Right now to customize DNS name resolver when using DnsAddressResolverGroup one should subclass implementation and override newNameResolver method when in fact it's possible to collect all settings in a DnsNameResolverBuilder instance. Described in #7749. Modifications: - Added new constructor for DnsNameResolverBuilder in order to delay EventLoop specification - Added copy() method to DnsNameResolverBuilder to provide an immutable copy of the builder - Added new single-argument constructor for DnsAddressResolverGroup and RoundRobinDnsAddressResolverGroup accepting DnsNameResolverBuilder instance - DnsAddressResolverGroup to build a new resolver using DnsNameResolverBuilder given instead of creating a new one - Test cases to check that changing channelFactory after the builder was passed to create a DnsNameResolverGroup would not propagate to the name resolver Result: Much easier to customize DNS settings w/o subclassing DnsAddressResolverGroup
127 lines
5.4 KiB
Java
127 lines
5.4 KiB
Java
/*
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* Copyright 2014 The Netty Project
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*
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* The Netty Project licenses this file to you under the Apache License,
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* version 2.0 (the "License"); you may not use this file except in compliance
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* with the License. You may obtain a copy of the License at:
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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* License for the specific language governing permissions and limitations
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* under the License.
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*/
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package io.netty.resolver.dns;
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import io.netty.channel.ChannelFactory;
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import io.netty.channel.EventLoop;
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import io.netty.channel.ReflectiveChannelFactory;
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import io.netty.channel.socket.DatagramChannel;
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import io.netty.resolver.AddressResolver;
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import io.netty.resolver.AddressResolverGroup;
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import io.netty.resolver.InetSocketAddressResolver;
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import io.netty.resolver.NameResolver;
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import io.netty.util.concurrent.EventExecutor;
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import io.netty.util.concurrent.Promise;
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import io.netty.util.internal.StringUtil;
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import io.netty.util.internal.UnstableApi;
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import java.net.InetAddress;
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import java.net.InetSocketAddress;
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import java.util.List;
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import java.util.concurrent.ConcurrentMap;
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import static io.netty.util.internal.PlatformDependent.newConcurrentHashMap;
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/**
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* A {@link AddressResolverGroup} of {@link DnsNameResolver}s.
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*/
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@UnstableApi
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public class DnsAddressResolverGroup extends AddressResolverGroup<InetSocketAddress> {
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private final DnsNameResolverBuilder dnsResolverBuilder;
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private final ConcurrentMap<String, Promise<InetAddress>> resolvesInProgress = newConcurrentHashMap();
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private final ConcurrentMap<String, Promise<List<InetAddress>>> resolveAllsInProgress = newConcurrentHashMap();
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public DnsAddressResolverGroup(DnsNameResolverBuilder dnsResolverBuilder) {
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this.dnsResolverBuilder = dnsResolverBuilder.copy();
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}
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public DnsAddressResolverGroup(
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Class<? extends DatagramChannel> channelType,
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DnsServerAddressStreamProvider nameServerProvider) {
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this(new DnsNameResolverBuilder());
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dnsResolverBuilder.channelType(channelType).nameServerProvider(nameServerProvider);
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}
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public DnsAddressResolverGroup(
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ChannelFactory<? extends DatagramChannel> channelFactory,
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DnsServerAddressStreamProvider nameServerProvider) {
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this(new DnsNameResolverBuilder());
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dnsResolverBuilder.channelFactory(channelFactory).nameServerProvider(nameServerProvider);
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}
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@SuppressWarnings("deprecation")
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@Override
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protected final AddressResolver<InetSocketAddress> newResolver(EventExecutor executor) throws Exception {
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if (!(executor instanceof EventLoop)) {
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throw new IllegalStateException(
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"unsupported executor type: " + StringUtil.simpleClassName(executor) +
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" (expected: " + StringUtil.simpleClassName(EventLoop.class));
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}
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// we don't really need to pass channelFactory and nameServerProvider separately,
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// but still keep this to ensure backward compatibility with (potentially) override methods
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return newResolver((EventLoop) executor,
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dnsResolverBuilder.channelFactory(),
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dnsResolverBuilder.nameServerProvider());
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}
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/**
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* @deprecated Override {@link #newNameResolver(EventLoop, ChannelFactory, DnsServerAddressStreamProvider)}.
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*/
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@Deprecated
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protected AddressResolver<InetSocketAddress> newResolver(
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EventLoop eventLoop, ChannelFactory<? extends DatagramChannel> channelFactory,
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DnsServerAddressStreamProvider nameServerProvider) throws Exception {
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final NameResolver<InetAddress> resolver = new InflightNameResolver<InetAddress>(
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eventLoop,
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newNameResolver(eventLoop, channelFactory, nameServerProvider),
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resolvesInProgress,
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resolveAllsInProgress);
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return newAddressResolver(eventLoop, resolver);
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}
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/**
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* Creates a new {@link NameResolver}. Override this method to create an alternative {@link NameResolver}
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* implementation or override the default configuration.
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*/
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protected NameResolver<InetAddress> newNameResolver(EventLoop eventLoop,
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ChannelFactory<? extends DatagramChannel> channelFactory,
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DnsServerAddressStreamProvider nameServerProvider)
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throws Exception {
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// once again, channelFactory and nameServerProvider are most probably set in builder already,
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// but I do reassign them again to avoid corner cases with override methods
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return dnsResolverBuilder.eventLoop(eventLoop)
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.channelFactory(channelFactory)
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.nameServerProvider(nameServerProvider)
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.build();
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}
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/**
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* Creates a new {@link AddressResolver}. Override this method to create an alternative {@link AddressResolver}
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* implementation or override the default configuration.
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*/
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protected AddressResolver<InetSocketAddress> newAddressResolver(EventLoop eventLoop,
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NameResolver<InetAddress> resolver)
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throws Exception {
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return new InetSocketAddressResolver(eventLoop, resolver);
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}
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}
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