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ensure AddressResolver supports localhost even if ipv6 is disabled in sysctl but not /etc/hosts #3285

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Merged
snazy merged 1 commit into from
Dec 17, 2025
Merged

ensure AddressResolver supports localhost even if ipv6 is disabled in sysctl but not /etc/hosts #3285

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32 changes: 26 additions & 6 deletions ...src/main/java/org/apache/polaris/persistence/nosql/quarkus/distcache/AddressResolver.java
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Original file line number Diff line number Diff line change
Expand Up @@ -35,6 +35,7 @@
import java.util.Set;
import java.util.stream.IntStream;
import java.util.stream.Stream;
import org.jspecify.annotations.NonNull;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

Expand All @@ -54,14 +55,27 @@ record AddressResolver(DnsClient dnsClient, List<String> searchList) {

static {
try {
IP_V4_ONLY = Boolean.parseBoolean(System.getProperty("java.net.preferIPv4Stack", "false"));
LOCAL_ADDRESSES =
networkInterfaces()
.flatMap(
ni ->
ni.getInterfaceAddresses().stream()
// Need to do this InetAddress->byte[]->InetAddress dance to get rid of
// host-address suffixes as in `0:0:0:0:0:0:0:1%lo`
.map(InterfaceAddress::getAddress)
Stream.concat(
// localhost can be ipv6 when sysctl disable ipv6
// if ::1 is registered for localhost in /etc/hosts
// in this case java stack can still capture it
// and it will work (even if not great)
// this is a workaround to ensure at least localhost is
// in the list but this could be more general to all /etc/hosts
// mappings
IP_V4_ONLY || !"lo".equalsIgnoreCase(ni.getName())
? Stream.empty()
: findLocalhostAddresses(),
ni.getInterfaceAddresses().stream()
// Need to do this InetAddress->byte[]->InetAddress dance to get
// rid of
// host-address suffixes as in `0:0:0:0:0:0:0:1%lo`
.map(InterfaceAddress::getAddress))
.map(InetAddress::getAddress)
.map(
a -> {
Expand All @@ -75,13 +89,19 @@ record AddressResolver(DnsClient dnsClient, List<String> searchList) {
})
.map(InetAddress::getHostAddress))
.collect(toUnmodifiableSet());

IP_V4_ONLY = Boolean.parseBoolean(System.getProperty("java.net.preferIPv4Stack", "false"));
} catch (SocketException e) {
throw new RuntimeException(e);
}
}

private static @NonNull Stream<InetAddress> findLocalhostAddresses() {
try {
return Stream.of(InetAddress.getAllByName("localhost"));
} catch (final RuntimeException | UnknownHostException e) {
return Stream.empty();
}
}

/**
* Uses a "default" {@link DnsClient} using the first {@code nameserver} and the {@code search}
* list configured in {@code /etc/resolv.conf}.
Expand Down