fdfe3149ba
Related issues: - #3971 - #3973 - #3976 - #4035 Motivation: 1. Previously, DnsNameResolver.query() retried the request query by its own. It prevents a user from deciding when to retry or stop. It is also impossible to get the response object whose code is not NOERROR. 2. NameResolver does not have an operation that resolves a host name into multiple addresses, like InetAddress.getAllByName() Modifications: - Changes related with DnsNameResolver.query() - Make query() not retry - Move the retry logic to DnsNameResolver.resolve() instead. - Make query() fail the promise only when I/O error occurred or it failed to get a response - Add DnsNameResolverException and use it when query() fails so that the resolver can give more information about the failure - query() does not cache anymore. - Changes related with NameResolver.resolveAll() - Add NameResolver.resolveAll() - Add SimpleNameResolver.doResolveAll() - Changes related with DnsNameResolver.resolve() and resolveAll() - Make DnsNameResolveContext abstract so that DnsNameResolver can decide to get single or multiple addresses from it - Re-implement cache so that the cache works for resolve() and resolveAll() - Add 'traceEnabled' property to enable/disable trace information - Miscellaneous changes - Use ObjectUtil.checkNotNull() wherever possible - Add InternetProtocolFamily.addressType() to remove repetitive switch-case blocks in DnsNameResolver(Context) - Do not raise an exception when decoding a truncated DNS response Result: - Full control over query() - A user can now retrieve all addresses via (Dns)NameResolver.resolveAll() - DNS cache works only for resolve() and resolveAll() now.
77 lines
2.1 KiB
Java
77 lines
2.1 KiB
Java
/*
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* Copyright 2015 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.EventLoop;
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import io.netty.util.concurrent.ScheduledFuture;
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import java.net.InetAddress;
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import java.util.concurrent.TimeUnit;
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final class DnsCacheEntry {
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private final String hostname;
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private final InetAddress address;
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private final Throwable cause;
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private volatile ScheduledFuture<?> expirationFuture;
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DnsCacheEntry(String hostname, InetAddress address) {
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this.hostname = hostname;
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this.address = address;
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cause = null;
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}
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DnsCacheEntry(String hostname, Throwable cause) {
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this.hostname = hostname;
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this.cause = cause;
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address = null;
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}
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String hostname() {
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return hostname;
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}
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InetAddress address() {
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return address;
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}
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Throwable cause() {
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return cause;
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}
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void scheduleExpiration(EventLoop loop, Runnable task, long delay, TimeUnit unit) {
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assert expirationFuture == null: "expiration task scheduled already";
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expirationFuture = loop.schedule(task, delay, unit);
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}
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void cancelExpiration() {
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ScheduledFuture<?> expirationFuture = this.expirationFuture;
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if (expirationFuture != null) {
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expirationFuture.cancel(false);
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}
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}
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@Override
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public String toString() {
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if (cause != null) {
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return hostname + '/' + cause;
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} else {
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return address.toString();
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}
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}
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}
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