c1b1d6268a
Motivation: At the moment there is not way for the user to know if resolving a domain was failed because the domain was unkown or because of an IO error / timeout. If it was caused by an timeout / IO error the user may want to retry the query. Also if the query was failed because of an IO error / timeout we should not cache it. Modifications: - Add DnsNameResolverTimeoutException and include it in the UnkownHostException if the domain could not be resolved because of an timeout. This will allow the user to retry the query when inspecting the cause. - Do not cache IO errors / timeouts - Add unit test Result: Easier for users to implement retries for DNS querys and not cache IO errors / timeouts.
79 lines
2.8 KiB
Java
79 lines
2.8 KiB
Java
/*
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* Copyright 2016 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.handler.codec.dns.DnsRecord;
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import io.netty.util.internal.UnstableApi;
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import java.net.InetAddress;
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import java.util.List;
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/**
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* A cache for DNS resolution entries.
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*/
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@UnstableApi
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public interface DnsCache {
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/**
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* Clears all the resolved addresses cached by this resolver.
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*
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* @see #clear(String)
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*/
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void clear();
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/**
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* Clears the resolved addresses of the specified host name from the cache of this resolver.
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*
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* @return {@code true} if and only if there was an entry for the specified host name in the cache and
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* it has been removed by this method
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*/
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boolean clear(String hostname);
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/**
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* Return the cached entries for the given hostname.
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* @param hostname the hostname
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* @param additionals the additional records
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* @return the cached entries
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*/
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List<? extends DnsCacheEntry> get(String hostname, DnsRecord[] additionals);
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/**
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* Create a new {@link DnsCacheEntry} and cache a resolved address for a given hostname.
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* @param hostname the hostname
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* @param additionals the additional records
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* @param address the resolved address
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* @param originalTtl the TLL as returned by the DNS server
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* @param loop the {@link EventLoop} used to register the TTL timeout
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* @return The {@link DnsCacheEntry} corresponding to this cache entry.
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*/
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DnsCacheEntry cache(String hostname, DnsRecord[] additionals, InetAddress address, long originalTtl,
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EventLoop loop);
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/**
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* Cache the resolution failure for a given hostname.
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* Be aware this <strong>won't</strong> be called with timeout / cancel / transport exceptions.
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*
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* @param hostname the hostname
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* @param additionals the additional records
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* @param cause the resolution failure
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* @param loop the {@link EventLoop} used to register the TTL timeout
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* @return The {@link DnsCacheEntry} corresponding to this cache entry, or {@code null} if this cache doesn't
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* support caching failed responses.
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*/
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DnsCacheEntry cache(String hostname, DnsRecord[] additionals, Throwable cause, EventLoop loop);
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}
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