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// Copyright Vespa.ai. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
package com.yahoo.vespa.hosted.provision.testutils;
import com.yahoo.vespa.hosted.provision.node.IP;
import com.yahoo.vespa.hosted.provision.persistence.NameResolver;
import java.net.UnknownHostException;
import java.util.Arrays;
import java.util.EnumSet;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Map;
import java.util.Objects;
import java.util.Optional;
import java.util.Set;
import java.util.concurrent.ThreadLocalRandom;
import java.util.stream.Collectors;
/**
* A mock DNS resolver. Can be configured to only answer specific lookups or any lookup.
*
* @author mpolden
*/
public class MockNameResolver implements NameResolver {
private final Map<String, Set<String>> records = new HashMap<>();
private boolean mockAnyLookup = false;
private boolean explicitReverseRecords = false;
public MockNameResolver addReverseRecord(String ipAddress, String hostname) {
addRecord(ipAddress, hostname);
return this;
}
public MockNameResolver addRecord(String hostname, String... ipAddress) {
Objects.requireNonNull(hostname, "hostname must be non-null");
Arrays.stream(ipAddress).forEach(ip -> Objects.requireNonNull(ip, "ipAddress must be non-null"));
records.computeIfAbsent(hostname, (k) -> new HashSet<>())
.addAll(Arrays.asList(ipAddress));
return this;
}
public MockNameResolver removeRecord(String name) {
records.remove(name);
return this;
}
public MockNameResolver mockAnyLookup() {
this.mockAnyLookup = true;
return this;
}
/**
* When true, only records added with {@link MockNameResolver#addReverseRecord(String, String)} are considered by
* {@link MockNameResolver#resolveHostname(String)}. Otherwise the latter returns the IP address by reversing the lookup
* implicitly.
*/
public MockNameResolver explicitReverseRecords() {
this.explicitReverseRecords = true;
return this;
}
@Override
public Set<String> resolveAll(String name) {
if (records.containsKey(name)) {
return records.get(name);
}
if (mockAnyLookup) {
records.computeIfAbsent(name, (k) -> new HashSet<>())
.add(randomIpAddress());
return records.get(name);
}
throw new RuntimeException(new UnknownHostException("Could not resolve: " + name));
}
@Override
public Set<String> resolve(String name, RecordType first, RecordType... rest) {
var types = EnumSet.of(first, rest);
return resolveAll(name)
.stream()
.filter(addressString -> {
if (types.contains(RecordType.A) && IP.isV4(addressString)) return true;
if (types.contains(RecordType.AAAA) && IP.isV6(addressString)) return true;
return false;
})
.collect(Collectors.toSet());
}
@Override
public Optional<String> resolveHostname(String ipAddress) {
if (!explicitReverseRecords) {
return records.entrySet().stream()
.filter(kv -> kv.getValue().contains(ipAddress))
.map(Map.Entry::getKey)
.findFirst();
}
return Optional.ofNullable(records.get(ipAddress))
.flatMap(values -> values.stream().findFirst());
}
private static String randomIpAddress() {
// Generate a random IP in 127/8 (loopback block)
ThreadLocalRandom random = ThreadLocalRandom.current();
return String.format("127.%d.%d.%d",
random.nextInt(1, 255 + 1),
random.nextInt(1, 255 + 1),
random.nextInt(1, 255 + 1));
}
}
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