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DefaultDnsCache should store more then one Entry per hostname. (#7906)

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Motivation:

Due a bug we did never store more then one address per hostname in DefaultDnsCache.

Modifications:

- Correctly store multiple entries per hostname
- Add tests

Result:

DefaultDnsCache correctly stores more then one entry. Also fixes https://github.com/netty/netty/issues/7882 .
This commit is contained in:
Norman Maurer 2018-05-04 14:19:26 +02:00 committed by GitHub
parent a598c3b69b
commit b83328606f
No known key found for this signature in database
GPG Key ID: 4AEE18F83AFDEB23
2 changed files with 78 additions and 8 deletions
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20
resolver-dns/src/main/java/io/netty/resolver/dns/DefaultDnsCache.java
View File

@ -170,9 +170,9 @@ public class DefaultDnsCache implements DnsCache {
Entries oldEntries = resolveCache.putIfAbsent(e.hostname(), entries);
if (oldEntries != null) {
entries = oldEntries;
entries.add(e);
}
}
entries.add(e);
scheduleCacheExpiration(e, ttl, loop);
}
@ -288,11 +288,27 @@ public class DefaultDnsCache implements DnsCache {
continue;
}
}
// Create a new List for COW semantics
List<DefaultDnsCacheEntry> newEntries = new ArrayList<DefaultDnsCacheEntry>(entries.size() + 1);
newEntries.addAll(entries);
DefaultDnsCacheEntry replacedEntry = null;
for (int i = 0; i < entries.size(); i++) {
DefaultDnsCacheEntry entry = entries.get(i);
// Only add old entry if the address is not the same as the one we try to add as well.
// In this case we will skip it and just add the new entry as this may have
// more up-to-date data and cancel the old after we were able to update the cache.
if (!e.address().equals(entry.address())) {
newEntries.add(entry);
} else {
assert replacedEntry == null;
replacedEntry = entry;
}
}
newEntries.add(e);
if (compareAndSet(entries, newEntries)) {
if (replacedEntry != null) {
replacedEntry.cancelExpiration();
}
return;
}
} else if (compareAndSet(entries, Collections.singletonList(e))) {

66
resolver-dns/src/test/java/io/netty/resolver/dns/DefaultDnsCacheTest.java
View File

@ -18,31 +18,40 @@ package io.netty.resolver.dns;
import io.netty.channel.DefaultEventLoopGroup;
import io.netty.channel.EventLoop;
import io.netty.channel.EventLoopGroup;
import io.netty.channel.nio.NioEventLoopGroup;
import io.netty.util.NetUtil;
import org.junit.Assert;
import org.junit.Test;
import java.net.InetAddress;
import java.util.List;
import java.util.concurrent.Callable;
import java.util.concurrent.TimeUnit;
import static org.junit.Assert.assertEquals;
import static org.junit.Assert.assertNotNull;
import static org.junit.Assert.assertNull;
public class DefaultDnsCacheTest {
@Test
public void testExpire() throws Throwable {
InetAddress addr1 = InetAddress.getByAddress(new byte[] { 10, 0, 0, 1 });
InetAddress addr2 = InetAddress.getByAddress(new byte[] { 10, 0, 0, 2 });
EventLoopGroup group = new DefaultEventLoopGroup(1);
try {
EventLoop loop = group.next();
final DefaultDnsCache cache = new DefaultDnsCache();
cache.cache("netty.io", null, NetUtil.LOCALHOST, 1, loop);
cache.cache("netty.io", null, NetUtil.LOCALHOST6, 10000, loop);
cache.cache("netty.io", null, addr1, 1, loop);
cache.cache("netty.io", null, addr2, 10000, loop);
Throwable error = loop.schedule(new Callable<Throwable>() {
@Override
public Throwable call() throws Exception {
public Throwable call() {
try {
Assert.assertNull(cache.get("netty.io", null));
assertNull(cache.get("netty.io", null));
return null;
} catch (Throwable cause) {
return cause;
@ -70,9 +79,54 @@ public class DefaultDnsCacheTest {
try {
EventLoop loop = group.next();
final DefaultDnsCache cache = new DefaultDnsCache();
Assert.assertNotNull(cache.cache("netty.io", null, NetUtil.LOCALHOST, days, loop));
assertNotNull(cache.cache("netty.io", null, NetUtil.LOCALHOST, days, loop));
} finally {
group.shutdownGracefully();
}
}
@Test
public void testAddMultipleAddressesForSameHostname() throws Exception {
InetAddress addr1 = InetAddress.getByAddress(new byte[] { 10, 0, 0, 1 });
InetAddress addr2 = InetAddress.getByAddress(new byte[] { 10, 0, 0, 2 });
EventLoopGroup group = new DefaultEventLoopGroup(1);
try {
EventLoop loop = group.next();
final DefaultDnsCache cache = new DefaultDnsCache();
cache.cache("netty.io", null, addr1, 1, loop);
cache.cache("netty.io", null, addr2, 10000, loop);
List<? extends DnsCacheEntry> entries = cache.get("netty.io", null);
assertEquals(2, entries.size());
assertEntry(entries.get(0), addr1);
assertEntry(entries.get(1), addr2);
} finally {
group.shutdownGracefully();
}
}
@Test
public void testAddSameAddressForSameHostname() throws Exception {
InetAddress addr1 = InetAddress.getByAddress(new byte[] { 10, 0, 0, 1 });
EventLoopGroup group = new DefaultEventLoopGroup(1);
try {
EventLoop loop = group.next();
final DefaultDnsCache cache = new DefaultDnsCache();
cache.cache("netty.io", null, addr1, 1, loop);
cache.cache("netty.io", null, addr1, 10000, loop);
List<? extends DnsCacheEntry> entries = cache.get("netty.io", null);
assertEquals(1, entries.size());
assertEntry(entries.get(0), addr1);
} finally {
group.shutdownGracefully();
}
}
private static void assertEntry(DnsCacheEntry entry, InetAddress address) {
assertEquals(address, entry.address());
assertNull(entry.cause());
}
}