@Test
void removedWhenNoCacheHit() throws Exception {
    try (TestDnsServer server = new TestDnsServer(ImmutableMap.of(
            new DefaultDnsQuestion("foo.com.", A),
            new DefaultDnsResponse(0).addRecord(ANSWER, newAddressRecord("foo.com.", "1.1.1.1", 1))))
    ) {
        final EventLoop eventLoop = eventLoopExtension.get();
        final DnsResolverGroupBuilder builder = builder(server);
        try (RefreshingAddressResolverGroup group = builder.build(eventLoop)) {
            final AddressResolver<InetSocketAddress> resolver = group.getResolver(eventLoop);

            final long start = System.nanoTime();

            final Future<InetSocketAddress> foo = resolver.resolve(
                    InetSocketAddress.createUnresolved("foo.com", 36462));
            await().untilAsserted(() -> assertThat(foo.isSuccess()).isTrue());
            assertThat(foo.getNow().getAddress().getHostAddress()).isEqualTo("1.1.1.1");

            final ConcurrentMap<String, CompletableFuture<CacheEntry>> cache = group.cache();
            await().until(cache::isEmpty);

            assertThat(System.nanoTime() - start).isGreaterThanOrEqualTo(
                    (long) (TimeUnit.SECONDS.toNanos(1) * 0.9));
        }
    }
}
 

@Test
void cacheClearWhenClosed() throws Exception {
    try (TestDnsServer server = new TestDnsServer(ImmutableMap.of(
            new DefaultDnsQuestion("foo.com.", A),
            new DefaultDnsResponse(0).addRecord(ANSWER, newAddressRecord("foo.com.", "1.1.1.1"))))
    ) {
        final EventLoop eventLoop = eventLoopExtension.get();
        final RefreshingAddressResolverGroup group = builder(server).build(eventLoop);
        final AddressResolver<InetSocketAddress> resolver = group.getResolver(eventLoop);
        final Future<InetSocketAddress> foo = resolver.resolve(
                InetSocketAddress.createUnresolved("foo.com", 36462));
        await().untilAsserted(() -> assertThat(foo.isSuccess()).isTrue());
        assertThat(foo.getNow().getAddress().getHostAddress()).isEqualTo("1.1.1.1");
        final ConcurrentMap<String, CompletableFuture<CacheEntry>> cache = group.cache();
        assertThat(cache.size()).isEqualTo(1);
        final CacheEntry cacheEntry = cache.get("foo.com").join();
        group.close();
        await().until(() -> {
            final ScheduledFuture<?> future = cacheEntry.refreshFuture;
            return future != null && future.isCancelled();
        });
        assertThat(cache).isEmpty();
    }
}
 

@Test
void timeout() {
    try (TestDnsServer server1 = new TestDnsServer(ImmutableMap.of(), new TimeoutHandler());
         TestDnsServer server2 = new TestDnsServer(ImmutableMap.of(), new TimeoutHandler());
         TestDnsServer server3 = new TestDnsServer(ImmutableMap.of(), new TimeoutHandler());
         TestDnsServer server4 = new TestDnsServer(ImmutableMap.of(), new TimeoutHandler());
         TestDnsServer server5 = new TestDnsServer(ImmutableMap.of(
                 new DefaultDnsQuestion("foo.com.", A),
                 new DefaultDnsResponse(0).addRecord(ANSWER, newAddressRecord("foo.com.", "1.1.1.1"))))) {

        final DnsResolverGroupBuilder builder = builder(server1, server2, server3, server4, server5)
                .negativeTtl(60)
                .queryTimeoutMillis(1000);
        final ClientFactory factory =
                ClientFactory.builder().addressResolverGroupFactory(builder::build).build();
        final WebClient client = WebClient.builder("http://foo.com").factory(factory).build();
        assertThatThrownBy(() -> client.get("/").aggregate().join())
                .hasCauseInstanceOf(UnprocessedRequestException.class)
                .hasRootCauseExactlyInstanceOf(DnsTimeoutException.class);
    }
}
 

@Test
void returnPartialDnsQuestions() throws Exception {
    // Returns IPv6 correctly and make IPv4 timeout.
    try (TestDnsServer server = new TestDnsServer(
            ImmutableMap.of(
                    new DefaultDnsQuestion("foo.com.", AAAA),
                    new DefaultDnsResponse(0).addRecord(ANSWER, newAddressRecord("foo.com.", "::1", 1))))
    ) {
        final EventLoop eventLoop = eventLoopExtension.get();
        final DnsResolverGroupBuilder builder = builder(server)
                .queryTimeoutMillis(1000)
                .resolvedAddressTypes(ResolvedAddressTypes.IPV4_PREFERRED);
        try (RefreshingAddressResolverGroup group = builder.build(eventLoop)) {
            final AddressResolver<InetSocketAddress> resolver = group.getResolver(eventLoop);
            final Future<InetSocketAddress> future = resolver.resolve(
                    InetSocketAddress.createUnresolved("foo.com", 36462));
            await().until(future::isDone);
            assertThat(future.getNow().getAddress().getHostAddress()).isEqualTo("0:0:0:0:0:0:0:1");
        }
    }
}
 

@Test
void preferredOrderIpv4() throws Exception {
    try (TestDnsServer server = new TestDnsServer(
            ImmutableMap.of(
                    new DefaultDnsQuestion("foo.com.", A),
                    new DefaultDnsResponse(0).addRecord(ANSWER, newAddressRecord("foo.com.", "1.1.1.1")),
                    new DefaultDnsQuestion("foo.com.", AAAA),
                    new DefaultDnsResponse(0).addRecord(ANSWER, newAddressRecord("foo.com.", "::1", 1))),
            new DelayHandler(A))
    ) {
        final EventLoop eventLoop = eventLoopExtension.get();
        final DnsResolverGroupBuilder builder = builder(server)
                .resolvedAddressTypes(ResolvedAddressTypes.IPV4_PREFERRED);
        try (RefreshingAddressResolverGroup group = builder.build(eventLoop)) {
            final AddressResolver<InetSocketAddress> resolver = group.getResolver(eventLoop);
            final Future<InetSocketAddress> future = resolver.resolve(
                    InetSocketAddress.createUnresolved("foo.com", 36462));
            await().until(future::isSuccess);
            assertThat(future.getNow().getAddress().getHostAddress()).isEqualTo("1.1.1.1");
        }
    }
}
 

@Test
void preferredOrderIpv6() throws Exception {
    try (TestDnsServer server = new TestDnsServer(
            ImmutableMap.of(
                    new DefaultDnsQuestion("foo.com.", A),
                    new DefaultDnsResponse(0).addRecord(ANSWER, newAddressRecord("foo.com.", "1.1.1.1")),
                    new DefaultDnsQuestion("foo.com.", AAAA),
                    new DefaultDnsResponse(0).addRecord(ANSWER, newAddressRecord("foo.com.", "::1", 1))),
            new DelayHandler(AAAA))
    ) {
        final EventLoop eventLoop = eventLoopExtension.get();
        final DnsResolverGroupBuilder builder = builder(server)
                .resolvedAddressTypes(ResolvedAddressTypes.IPV6_PREFERRED);
        try (RefreshingAddressResolverGroup group = builder.build(eventLoop)) {
            final AddressResolver<InetSocketAddress> resolver = group.getResolver(eventLoop);
            final Future<InetSocketAddress> future = resolver.resolve(
                    InetSocketAddress.createUnresolved("foo.com", 36462));
            await().until(future::isSuccess);
            assertThat(future.getNow().getAddress().getHostAddress()).isEqualTo("0:0:0:0:0:0:0:1");
        }
    }
}
 

@Test
public void srv() throws Exception {
    try (TestDnsServer server = new TestDnsServer(ImmutableMap.of(
            new DefaultDnsQuestion("foo.com.", SRV),
            new DefaultDnsResponse(0).addRecord(ANSWER, newSrvRecord("foo.com.", 1, 2, "a.foo.com."))
                                     .addRecord(ANSWER, newSrvRecord("foo.com.", 3, 4, "b.foo.com."))
                                     .addRecord(ANSWER, newSrvRecord("unrelated.com.", 0, 0, "asdf.com."))
                                     .addRecord(ANSWER, newTooShortSrvRecord("foo.com."))
                                     .addRecord(ANSWER, newBadNameSrvRecord("foo.com."))
    ))) {
        try (DnsServiceEndpointGroup group =
                     DnsServiceEndpointGroup.builder("foo.com")
                                            .serverAddresses(server.addr())
                                            .build()) {

            assertThat(group.whenReady().get()).containsExactly(
                    Endpoint.of("a.foo.com", 2).withWeight(1),
                    Endpoint.of("b.foo.com", 4).withWeight(3));
        }
    }
}
 

@Test
public void cname() throws Exception {
    try (TestDnsServer server = new TestDnsServer(ImmutableMap.of(
            new DefaultDnsQuestion("bar.com.", SRV),
            new DefaultDnsResponse(0).addRecord(ANSWER, newCnameRecord("bar.com.", "baz.com."))
                                     .addRecord(ANSWER, newSrvRecord("baz.com.", 5, 6, "c.baz.com."))
    ))) {
        try (DnsServiceEndpointGroup group =
                     DnsServiceEndpointGroup.builder("bar.com")
                                            .serverAddresses(server.addr())
                                            .build()) {

            assertThat(group.whenReady().get()).containsExactly(
                    Endpoint.of("c.baz.com", 6).withWeight(5));
        }
    }
}
 

@Test
public void ipV4Only() throws Exception {
    try (TestDnsServer server = new TestDnsServer(ImmutableMap.of(
            new DefaultDnsQuestion("foo.com.", A),
            new DefaultDnsResponse(0).addRecord(ANSWER, newAddressRecord("foo.com.", "1.1.1.1"))
                                     .addRecord(ANSWER, newAddressRecord("unrelated.com", "1.2.3.4")),
            new DefaultDnsQuestion("foo.com.", AAAA),
            new DefaultDnsResponse(0).addRecord(ANSWER, newAddressRecord("foo.com.", "::1"))
    ))) {
        try (DnsAddressEndpointGroup group =
                     DnsAddressEndpointGroup.builder("foo.com")
                                            .port(8080)
                                            .serverAddresses(server.addr())
                                            .resolvedAddressTypes(ResolvedAddressTypes.IPV4_ONLY)
                                            .build()) {

            assertThat(group.whenReady().get()).containsExactly(
                    Endpoint.of("foo.com", 8080).withIpAddr("1.1.1.1"));
        }
    }
}
 

@Test
public void ipV6Only() throws Exception {
    try (TestDnsServer server = new TestDnsServer(ImmutableMap.of(
            new DefaultDnsQuestion("bar.com.", A),
            new DefaultDnsResponse(0).addRecord(ANSWER, newAddressRecord("bar.com.", "1.1.1.1")),
            new DefaultDnsQuestion("bar.com.", AAAA),
            new DefaultDnsResponse(0).addRecord(ANSWER, newAddressRecord("bar.com.", "::1"))
                                     .addRecord(ANSWER, newAddressRecord("bar.com.", "::1234:5678:90ab"))
                                     .addRecord(ANSWER, newAddressRecord("bar.com.",
                                                                         "2404:6800:4004:806::2013"))
    ))) {
        try (DnsAddressEndpointGroup group =
                     DnsAddressEndpointGroup.builder("bar.com")
                                            .port(8080)
                                            .serverAddresses(server.addr())
                                            .resolvedAddressTypes(ResolvedAddressTypes.IPV6_ONLY)
                                            .build()) {

            assertThat(group.whenReady().get(10, TimeUnit.SECONDS)).containsExactly(
                    Endpoint.of("bar.com", 8080).withIpAddr("2404:6800:4004:806::2013"),
                    Endpoint.of("bar.com", 8080).withIpAddr("::1"),
                    Endpoint.of("bar.com", 8080).withIpAddr("::1234:5678:90ab"));
        }
    }
}
 

@Test
public void ipV4AndIpV6() throws Exception {
    try (TestDnsServer server = new TestDnsServer(ImmutableMap.of(
            new DefaultDnsQuestion("baz.com.", A),
            new DefaultDnsResponse(0).addRecord(ANSWER, newAddressRecord("baz.com.", "1.1.1.1")),
            new DefaultDnsQuestion("baz.com.", AAAA),
            new DefaultDnsResponse(0).addRecord(ANSWER, newAddressRecord("baz.com.", "::1"))
    ))) {
        try (DnsAddressEndpointGroup group =
                     DnsAddressEndpointGroup.builder("baz.com")
                                            .port(8080)
                                            .serverAddresses(server.addr())
                                            .resolvedAddressTypes(ResolvedAddressTypes.IPV4_PREFERRED)
                                            .build()) {

            assertThat(group.whenReady().get()).containsExactly(
                    Endpoint.of("baz.com", 8080).withIpAddr("1.1.1.1"),
                    Endpoint.of("baz.com", 8080).withIpAddr("::1"));
        }
    }
}
 

@Test
public void platformDefault() throws Exception {
    try (TestDnsServer server = new TestDnsServer(ImmutableMap.of(
            new DefaultDnsQuestion("baz.com.", A),
            new DefaultDnsResponse(0).addRecord(ANSWER, newAddressRecord("baz.com.", "1.1.1.1")),
            new DefaultDnsQuestion("baz.com.", AAAA),
            new DefaultDnsResponse(0).addRecord(ANSWER, newAddressRecord("baz.com.", "::1"))
    ))) {
        try (DnsAddressEndpointGroup group =
                     DnsAddressEndpointGroup.builder("baz.com")
                                            .port(8080)
                                            .serverAddresses(server.addr())
                                            .build()) {

            assertThat(group.whenReady().get()).contains(
                    Endpoint.of("baz.com", 8080).withIpAddr("1.1.1.1"));
        }
    }
}
 

@Test
public void cname() throws Exception {
    try (TestDnsServer server = new TestDnsServer(ImmutableMap.of(
            new DefaultDnsQuestion("a.com.", A),
            new DefaultDnsResponse(0).addRecord(ANSWER, newBadAddressRecord("a.com.", true))
                                     .addRecord(ANSWER, newCnameRecord("a.com.", "b.com."))
                                     .addRecord(ANSWER, newAddressRecord("b.com.", "1.1.1.1")),
            new DefaultDnsQuestion("a.com.", AAAA),
            new DefaultDnsResponse(0).addRecord(ANSWER, newBadAddressRecord("a.com.", false))
                                     .addRecord(ANSWER, newCnameRecord("a.com.", "b.com."))
                                     .addRecord(ANSWER, newAddressRecord("b.com.", "::1"))
    ))) {
        try (DnsAddressEndpointGroup group =
                     DnsAddressEndpointGroup.builder("a.com")
                                            .port(8080)
                                            .serverAddresses(server.addr())
                                            .resolvedAddressTypes(ResolvedAddressTypes.IPV4_PREFERRED)
                                            .build()) {

            assertThat(group.whenReady().get()).containsExactly(
                    Endpoint.of("a.com", 8080).withIpAddr("1.1.1.1"),
                    Endpoint.of("a.com", 8080).withIpAddr("::1"));
        }
    }
}
 

@Test
public void mixedLoopbackAddresses() throws Exception {
    try (TestDnsServer server = new TestDnsServer(ImmutableMap.of(
            new DefaultDnsQuestion("foo.com.", A),
            new DefaultDnsResponse(0).addRecord(ANSWER, newAddressRecord("foo.com.", "127.0.0.1")),
            new DefaultDnsQuestion("foo.com.", AAAA),
            new DefaultDnsResponse(0).addRecord(ANSWER, newAddressRecord("foo.com.", "::1"))
    ))) {
        try (DnsAddressEndpointGroup group =
                     DnsAddressEndpointGroup.builder("foo.com")
                                            .port(8080)
                                            .serverAddresses(server.addr())
                                            .resolvedAddressTypes(ResolvedAddressTypes.IPV4_PREFERRED)
                                            .build()) {

            assertThat(group.whenReady().get()).containsExactly(
                    Endpoint.of("foo.com", 8080).withIpAddr("127.0.0.1"));
        }
    }
}
 

@Test
public void ipV4MappedOrCompatibleAddresses() throws Exception {
    try (TestDnsServer server = new TestDnsServer(ImmutableMap.of(
            new DefaultDnsQuestion("bar.com.", AAAA),
            new DefaultDnsResponse(0).addRecord(ANSWER, newCompatibleAddressRecord("bar.com.", "1.1.1.1"))
                                     .addRecord(ANSWER, newCompatibleAddressRecord("bar.com.", "1.1.1.2"))
                                     .addRecord(ANSWER, newMappedAddressRecord("bar.com.", "1.1.1.1"))
                                     .addRecord(ANSWER, newMappedAddressRecord("bar.com.", "1.1.1.3"))
    ))) {
        try (DnsAddressEndpointGroup group =
                     DnsAddressEndpointGroup.builder("bar.com")
                                            .port(8080)
                                            .serverAddresses(server.addr())
                                            .resolvedAddressTypes(ResolvedAddressTypes.IPV6_ONLY)
                                            .build()) {

            assertThat(group.whenReady().get()).containsExactly(
                    Endpoint.of("bar.com", 8080).withIpAddr("1.1.1.1"),
                    Endpoint.of("bar.com", 8080).withIpAddr("1.1.1.2"),
                    Endpoint.of("bar.com", 8080).withIpAddr("1.1.1.3"));
        }
    }
}
 

@Test
public void noPort() throws Exception {
    try (TestDnsServer server = new TestDnsServer(ImmutableMap.of(
            new DefaultDnsQuestion("no-port.com.", A),
            new DefaultDnsResponse(0).addRecord(ANSWER, newAddressRecord("no-port.com", "1.1.1.1"))
    ))) {
        try (DnsAddressEndpointGroup group =
                     DnsAddressEndpointGroup.builder("no-port.com")
                                            .serverAddresses(server.addr())
                                            .resolvedAddressTypes(ResolvedAddressTypes.IPV4_ONLY)
                                            .build()) {

            assertThat(group.whenReady().get()).containsExactly(
                    Endpoint.of("no-port.com").withIpAddr("1.1.1.1"));
        }
    }
}
 

@EnumSource(value = ResolvedAddressTypes.class, names = { "IPV4_PREFERRED", "IPV6_PREFERRED" })
@ParameterizedTest
public void partialIpV4Response(ResolvedAddressTypes resolvedAddressTypes) throws Exception {
    try (TestDnsServer server = new TestDnsServer(ImmutableMap.of(
            // Respond A record only.
            // Respond with NXDOMAIN for AAAA.
            new DefaultDnsQuestion("partial.com.", A),
            new DefaultDnsResponse(0).addRecord(ANSWER, newAddressRecord("partial.com", "1.1.1.1"))
    ))) {
        try (DnsAddressEndpointGroup group =
                     DnsAddressEndpointGroup.builder("partial.com")
                                            .serverAddresses(server.addr())
                                            .resolvedAddressTypes(resolvedAddressTypes)
                                            .backoff(Backoff.fixed(500))
                                            .build()) {

            assertThat(group.whenReady().get()).containsExactly(
                    Endpoint.of("partial.com").withIpAddr("1.1.1.1"));
        }
    }
}
 

@EnumSource(value = ResolvedAddressTypes.class, names = { "IPV4_PREFERRED", "IPV6_PREFERRED" })
@ParameterizedTest
public void partialIpV6Response(ResolvedAddressTypes resolvedAddressTypes) throws Exception {
    try (TestDnsServer server = new TestDnsServer(ImmutableMap.of(
            // Respond AAAA record only.
            // Respond with NXDOMAIN for A.
            new DefaultDnsQuestion("partial.com.", AAAA),
            new DefaultDnsResponse(0).addRecord(ANSWER, newAddressRecord("partial.com", "::1"))
    ))) {
        try (DnsAddressEndpointGroup group =
                     DnsAddressEndpointGroup.builder("partial.com")
                                            .serverAddresses(server.addr())
                                            .resolvedAddressTypes(resolvedAddressTypes)
                                            .backoff(Backoff.fixed(500))
                                            .build()) {

            assertThat(group.whenReady().get()).containsExactly(
                    Endpoint.of("partial.com").withIpAddr("::1"));
        }
    }
}
 

private static DnsQuestion newQuestion(String hostname, DnsRecordType type) {
    try {
        return new DefaultDnsQuestion(hostname, type);
    } catch (IllegalArgumentException e) {
        // java.net.IDN.toASCII(...) may throw an IllegalArgumentException if it fails to parse the hostname
        return null;
    }
}
 

@Test
void refreshing() throws Exception {
    try (TestDnsServer server = new TestDnsServer(ImmutableMap.of(
            new DefaultDnsQuestion("baz.com.", A),
            new DefaultDnsResponse(0).addRecord(ANSWER, newAddressRecord("baz.com.", "1.1.1.1", 1))))
    ) {
        final EventLoop eventLoop = eventLoopExtension.get();
        try (RefreshingAddressResolverGroup group = builder(server).build(eventLoop)) {
            final AddressResolver<InetSocketAddress> resolver = group.getResolver(eventLoop);

            final long start = System.nanoTime();

            final Future<InetSocketAddress> foo = resolver.resolve(
                    InetSocketAddress.createUnresolved("baz.com", 36462));
            await().untilAsserted(() -> assertThat(foo.isSuccess()).isTrue());
            assertThat(foo.getNow().getAddress().getHostAddress()).isEqualTo("1.1.1.1");

            final ConcurrentMap<String, CompletableFuture<CacheEntry>> cache = group.cache();
            assertThat(cache.size()).isOne();
            assertThat(cache.get("baz.com").join().address()).isEqualTo(
                    InetAddress.getByAddress("baz.com", new byte[] { 1, 1, 1, 1 }));

            // Resolve one more to increase cache hits.
            resolver.resolve(InetSocketAddress.createUnresolved("baz.com", 36462));

            server.setResponses(ImmutableMap.of(
                    new DefaultDnsQuestion("baz.com.", A),
                    new DefaultDnsResponse(0).addRecord(ANSWER, newAddressRecord("baz.com.", "2.2.2.2"))));

            await().until(() -> {
                final CompletableFuture<CacheEntry> future = cache.get("baz.com");
                return future != null && future.join().address().equals(
                        InetAddress.getByAddress("baz.com", new byte[] { 2, 2, 2, 2 }));
            });

            assertThat(System.nanoTime() - start).isGreaterThanOrEqualTo(
                    (long) (TimeUnit.SECONDS.toNanos(1) * 0.9)); // ttl 2 seconds * buffer (90%)
        }
    }
}
 

@Test
public void txt() throws Exception {
    try (TestDnsServer server = new TestDnsServer(ImmutableMap.of(
            new DefaultDnsQuestion("foo.com.", TXT),
            new DefaultDnsResponse(0).addRecord(ANSWER, newTxtRecord("foo.com.", "endpoint=a.foo.com"))
                                     .addRecord(ANSWER, newTxtRecord("foo.com.", "endpoint=b.foo.com"))
                                     .addRecord(ANSWER, newTxtRecord("unrelated.com.", "endpoint=c.com"))
                                     .addRecord(ANSWER, newTooShortTxtRecord("foo.com."))
                                     .addRecord(ANSWER, newTooLongTxtRecord("foo.com."))
                                     .addRecord(ANSWER, newTxtRecord("foo.com.", "unrelated_txt"))
                                     .addRecord(ANSWER, newTxtRecord("foo.com.", "endpoint=group:foo"))
                                     .addRecord(ANSWER, newTxtRecord("foo.com.", "endpoint=b:a:d"))
    ))) {
        try (DnsTextEndpointGroup group = DnsTextEndpointGroup.builder("foo.com", txt -> {
            final String txtStr = new String(txt, StandardCharsets.US_ASCII);
            if (txtStr.startsWith("endpoint=")) {
                return Endpoint.parse(txtStr.substring(9));
            } else {
                return null;
            }
        }).serverAddresses(server.addr()).build()) {

            assertThat(group.whenReady().get()).containsExactly(
                    Endpoint.of("a.foo.com"),
                    Endpoint.of("b.foo.com"));
        }
    }
}
 

@Test
public void noPort() throws Exception {
    try (TestDnsServer server = new TestDnsServer(ImmutableMap.of(
            new DefaultDnsQuestion("no-port.com.", SRV),
            new DefaultDnsResponse(0).addRecord(ANSWER, newSrvRecord("no-port.com.", 7, 0, "d.no-port.com"))
    ))) {
        try (DnsServiceEndpointGroup group =
                     DnsServiceEndpointGroup.builder("no-port.com")
                                            .serverAddresses(server.addr()).build()) {
            assertThat(group.whenReady().get()).containsExactly(
                    Endpoint.of("d.no-port.com"));
        }
    }
}
 

@Test
public void backoff() throws Exception {
    try (TestDnsServer server = new TestDnsServer(ImmutableMap.of())) { // Respond nothing.
        try (DnsAddressEndpointGroup group =
                     DnsAddressEndpointGroup.builder("backoff.com")
                                            .serverAddresses(server.addr())
                                            .resolvedAddressTypes(ResolvedAddressTypes.IPV4_PREFERRED)
                                            .backoff(Backoff.fixed(500))
                                            .build()) {

            await().untilAsserted(() -> assertThat(group.attemptsSoFar).isGreaterThan(2));
            assertThat(group.endpoints()).isEmpty();

            // Start to respond correctly.
            server.setResponses(ImmutableMap.of(
                    new DefaultDnsQuestion("backoff.com.", A),
                    new DefaultDnsResponse(0)
                            .addRecord(ANSWER, newAddressRecord("backoff.com", "1.1.1.1", 1)),
                    new DefaultDnsQuestion("backoff.com.", AAAA),
                    new DefaultDnsResponse(0)
                            .addRecord(ANSWER, newAddressRecord("backoff.com", "::1", 1))));

            await().untilAsserted(() -> assertThat(group.endpoints()).containsExactly(
                    Endpoint.of("backoff.com").withIpAddr("1.1.1.1"),
                    Endpoint.of("backoff.com").withIpAddr("::1")));
        }
    }
}
 

@Test
public void backoffOnEmptyResponse() throws Exception {
    try (TestDnsServer server = new TestDnsServer(ImmutableMap.of(
            // Respond with empty records.
            new DefaultDnsQuestion("empty.com.", A), new DefaultDnsResponse(0),
            new DefaultDnsQuestion("empty.com.", AAAA), new DefaultDnsResponse(0)
    ))) {
        try (DnsAddressEndpointGroup group =
                     DnsAddressEndpointGroup.builder("empty.com")
                                            .serverAddresses(server.addr())
                                            .resolvedAddressTypes(ResolvedAddressTypes.IPV4_PREFERRED)
                                            .backoff(Backoff.fixed(500))
                                            .build()) {

            await().untilAsserted(() -> assertThat(group.attemptsSoFar).isGreaterThan(2));
            assertThat(group.endpoints()).isEmpty();

            // Start to respond correctly.
            server.setResponses(ImmutableMap.of(
                    new DefaultDnsQuestion("empty.com.", A),
                    new DefaultDnsResponse(0)
                            .addRecord(ANSWER, newAddressRecord("empty.com", "1.1.1.1", 1)),
                    new DefaultDnsQuestion("empty.com.", AAAA),
                    new DefaultDnsResponse(0)
                            .addRecord(ANSWER, newAddressRecord("empty.com", "::1", 1))));

            await().untilAsserted(() -> assertThat(group.endpoints()).containsExactly(
                    Endpoint.of("empty.com").withIpAddr("1.1.1.1"),
                    Endpoint.of("empty.com").withIpAddr("::1")));
        }
    }
}
 

private static void queryMx(
        DnsNameResolver resolver,
        Map<String, Future<AddressedEnvelope<DnsResponse, InetSocketAddress>>> futures,
        String hostname) throws Exception {
    futures.put(hostname, resolver.query(new DefaultDnsQuestion(hostname, DnsRecordType.MX)));
}
 

@Test
void resolve() throws Exception {
    try (TestDnsServer server = new TestDnsServer(ImmutableMap.of(
            new DefaultDnsQuestion("foo.com.", A),
            new DefaultDnsResponse(0).addRecord(ANSWER, newAddressRecord("foo.com.", "1.1.1.1")),
            new DefaultDnsQuestion("bar.com.", A),
            new DefaultDnsResponse(0).addRecord(ANSWER, newAddressRecord("bar.com.", "1.2.3.4"))))
    ) {
        final EventLoop eventLoop = eventLoopExtension.get();
        try (RefreshingAddressResolverGroup group = builder(server).build(eventLoop)) {
            final AddressResolver<InetSocketAddress> resolver = group.getResolver(eventLoop);
            final Future<InetSocketAddress> foo = resolver.resolve(
                    InetSocketAddress.createUnresolved("foo.com", 36462));
            await().untilAsserted(() -> assertThat(foo.isSuccess()).isTrue());
            InetSocketAddress addr = foo.getNow();
            assertThat(addr.getAddress().getHostAddress()).isEqualTo("1.1.1.1");
            assertThat(addr.getPort()).isEqualTo(36462);

            final ConcurrentMap<String, CompletableFuture<CacheEntry>> cache = group.cache();
            assertThat(cache.size()).isOne();

            final Future<InetSocketAddress> bar = resolver.resolve(
                    InetSocketAddress.createUnresolved("bar.com", 36462));
            await().untilAsserted(() -> assertThat(bar.isSuccess()).isTrue());
            addr = bar.getNow();
            assertThat(addr.getAddress().getHostAddress()).isEqualTo("1.2.3.4");
            assertThat(addr.getPort()).isEqualTo(36462);
            assertThat(cache.size()).isEqualTo(2);

            final Future<InetSocketAddress> foo1 = resolver.resolve(
                    InetSocketAddress.createUnresolved("foo.com", 80));
            addr = foo1.getNow();
            assertThat(addr.getAddress().getHostAddress()).isEqualTo("1.1.1.1");
            assertThat(addr.getPort()).isEqualTo(80);
            assertThat(cache.size()).isEqualTo(2);

            final List<InetAddress> addresses =
                    cache.values()
                         .stream()
                         .map(future -> future.join().address())
                         .collect(toImmutableList());
            assertThat(addresses).containsExactlyInAnyOrder(
                    InetAddress.getByAddress("foo.com", new byte[] { 1, 1, 1, 1 }),
                    InetAddress.getByAddress("bar.com", new byte[] { 1, 2, 3, 4 }));
        }
    }
}
 

@Test
void removedWhenExceedingBackoffMaxAttempts() throws Exception {
    try (TestDnsServer server = new TestDnsServer(ImmutableMap.of(
            new DefaultDnsQuestion("foo.com.", A),
            new DefaultDnsResponse(0).addRecord(ANSWER, newAddressRecord("foo.com.", "1.1.1.1", 1))))
    ) {
        final EventLoop eventLoop = eventLoopExtension.get();
        final DnsResolverGroupBuilder builder = builder(server);
        builder.refreshBackoff(Backoff.ofDefault().withMaxAttempts(1));
        try (RefreshingAddressResolverGroup group = builder.build(eventLoop)) {
            final AddressResolver<InetSocketAddress> resolver = group.getResolver(eventLoop);

            final long start = System.nanoTime();

            final Future<InetSocketAddress> foo = resolver.resolve(
                    InetSocketAddress.createUnresolved("foo.com", 36462));
            await().untilAsserted(() -> assertThat(foo.isSuccess()).isTrue());
            assertThat(foo.getNow().getAddress().getHostAddress()).isEqualTo("1.1.1.1");

            server.setResponses(ImmutableMap.of());

            // Schedule resolve() every 500 millis to keep cache hits greater than 0.
            for (int i = 1; i <= 4; i++) {
                eventLoop.schedule(
                        () -> resolver.resolve(InetSocketAddress.createUnresolved("foo.com", 36462)),
                        500 * i, TimeUnit.MILLISECONDS);
            }

            final ConcurrentMap<String, CompletableFuture<CacheEntry>> cache = group.cache();
            await().until(cache::isEmpty);

            assertThat(System.nanoTime() - start).isGreaterThanOrEqualTo(
                    (long) (TimeUnit.SECONDS.toNanos(1) * 0.9)); // buffer (90%)

            final Future<InetSocketAddress> future = resolver.resolve(
                    InetSocketAddress.createUnresolved("foo.com", 36462));
            await().until(future::isDone);
            assertThat(future.cause()).isInstanceOf(UnknownHostException.class);
        }
    }
}
 

private void resolveAddress() {
    boolean debug = getFlag(BuiltinFlags.PRINT_DEBUG, false);

    String name = this.getPacketProtocol().getSRVRecordPrefix() + "._tcp." + this.getHost();
    if(debug) {
        System.out.println("[PacketLib] Attempting SRV lookup for \"" + name + "\".");
    }

    AddressedEnvelope<DnsResponse, InetSocketAddress> envelope = null;
    try(DnsNameResolver resolver = new DnsNameResolverBuilder(this.group.next())
            .channelType(NioDatagramChannel.class)
            .build()) {
        envelope = resolver.query(new DefaultDnsQuestion(name, DnsRecordType.SRV)).get();
        DnsResponse response = envelope.content();
        if(response.count(DnsSection.ANSWER) > 0) {
            DefaultDnsRawRecord record = response.recordAt(DnsSection.ANSWER, 0);
            if(record.type() == DnsRecordType.SRV) {
                ByteBuf buf = record.content();
                buf.skipBytes(4); // Skip priority and weight.

                int port = buf.readUnsignedShort();
                String host = DefaultDnsRecordDecoder.decodeName(buf);
                if(host.endsWith(".")) {
                    host = host.substring(0, host.length() - 1);
                }

                if(debug) {
                    System.out.println("[PacketLib] Found SRV record containing \"" + host + ":" + port + "\".");
                }

                this.host = host;
                this.port = port;
            } else if(debug) {
                System.out.println("[PacketLib] Received non-SRV record in response.");
            }
        } else if(debug) {
            System.out.println("[PacketLib] No SRV record found.");
        }
    } catch(Exception e) {
        if(debug) {
            System.out.println("[PacketLib] Failed to resolve SRV record.");
            e.printStackTrace();
        }
    } finally {
        if(envelope != null) {
            envelope.release();
        }
    }
}
 

private List<DnsRecord> lookupRecords() throws InterruptedException, ExecutionException, TimeoutException {
    return resolver.resolveAll(new DefaultDnsQuestion(query, DnsRecordType.SRV), Collections.emptyList())
        .get(resolveTimeout.getMillis(), TimeUnit.MILLISECONDS);
}