InetAddressResolver works on jdk21

build.gradle

@@ -22,7 +22,7 @@ apply plugin: 'com.palantir.baseline'
 apply plugin: 'com.palantir.baseline-java-versions'
 
 javaVersions {
-    libraryTarget = 8
+    libraryTarget = 11
     runtime = 17
 }
 

changelog/@unreleased/pr-574.v2.yml

@@ -0,0 +1,5 @@
+type: improvement
+improvement:
+  description: InetAddressResolver works compiled against jdk21
+  links:
+  - https://github.com/palantir/docker-proxy-rule/pull/574

docker-proxy-rule-core-jdk21/build.gradle

@@ -0,0 +1,19 @@
+apply plugin: 'com.palantir.external-publish-jar'
+
+dependencies {
+    api project(':docker-proxy-rule-core')
+
+    testImplementation group: 'junit', name: 'junit'
+    testImplementation group: 'org.assertj', name: 'assertj-core'
+    testImplementation group: 'org.mockito', name: 'mockito-core'
+    testRuntimeOnly group: 'org.mockito', name: 'mockito-inline'
+}
+
+javaVersion {
+    target = 21
+    runtime = 21
+}
+
+moduleJvmArgs {
+    opens 'java.base/java.net'
+}

docker-proxy-rule-core-jdk21/src/main/java/com/palantir/docker/proxy/DockerProxyInetAddressResolver.java

@@ -0,0 +1,42 @@
+/*
+ * (c) Copyright 2024 Palantir Technologies Inc. All rights reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.palantir.docker.proxy;
+
+import java.net.InetAddress;
+import java.net.UnknownHostException;
+import java.net.spi.InetAddressResolver;
+import java.util.Arrays;
+import java.util.function.Supplier;
+import java.util.stream.Stream;
+
+public final class DockerProxyInetAddressResolver implements InetAddressResolver {
+    private final Supplier<DockerNameService> dockerNameService;
+
+    public DockerProxyInetAddressResolver(Supplier<DockerNameService> dockerNameService) {
+        this.dockerNameService = dockerNameService;
+    }
+
+    @Override
+    public Stream<InetAddress> lookupByName(String host, LookupPolicy _lookupPolicy) throws UnknownHostException {
+        return Arrays.stream(dockerNameService.get().lookupAllHostAddr(host));
+    }
+
+    @Override
+    public String lookupByAddress(byte[] addr) throws UnknownHostException {
+        return dockerNameService.get().getHostByAddr(addr);
+    }
+}

docker-proxy-rule-core-jdk21/src/main/java/com/palantir/docker/proxy/DockerProxyInetAddressResolverProvider.java

@@ -0,0 +1,36 @@
+/*
+ * (c) Copyright 2024 Palantir Technologies Inc. All rights reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.palantir.docker.proxy;
+
+import java.net.spi.InetAddressResolver;
+import java.net.spi.InetAddressResolverProvider;
+
+public final class DockerProxyInetAddressResolverProvider extends InetAddressResolverProvider {
+
+    @Override
+    public InetAddressResolver get(Configuration configuration) {
+        return new ForwardingInetAddressResolver(
+                new DockerProxyInetAddressResolver(DockerProxyManager::getDockerNameService),
+                configuration.builtinResolver(),
+                () -> DockerProxyManager.getDockerNameService() != null);
+    }
+
+    @Override
+    public String name() {
+        return "DockerProxyInetAddressResolverProvider";
+    }
+}

docker-proxy-rule-core-jdk21/src/main/java/com/palantir/docker/proxy/ForwardingInetAddressResolver.java

@@ -0,0 +1,68 @@
+/*
+ * (c) Copyright 2024 Palantir Technologies Inc. All rights reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.palantir.docker.proxy;
+
+import java.net.InetAddress;
+import java.net.UnknownHostException;
+import java.net.spi.InetAddressResolver;
+import java.util.function.Supplier;
+import java.util.stream.Stream;
+
+class ForwardingInetAddressResolver implements InetAddressResolver {
+    private final InetAddressResolver delegate;
+    private final InetAddressResolver fallback;
+    private final Supplier<Boolean> delegateEnabled;
+
+    ForwardingInetAddressResolver(
+            InetAddressResolver delegate, InetAddressResolver fallback, Supplier<Boolean> delegateEnabled) {
+        this.delegate = delegate;
+        this.fallback = fallback;
+        this.delegateEnabled = delegateEnabled;
+    }
+
+    @Override
+    public Stream<InetAddress> lookupByName(String host, LookupPolicy lookupPolicy) throws UnknownHostException {
+        if (!delegateEnabled.get()) {
+            return fallback.lookupByName(host, lookupPolicy);
+        }
+
+        try {
+            return delegate.lookupByName(host, lookupPolicy);
+        } catch (UnknownHostException e) {
+            if (fallback != null) {
+                return fallback.lookupByName(host, lookupPolicy);
+            }
+            throw e;
+        }
+    }
+
+    @Override
+    public String lookupByAddress(byte[] addr) throws UnknownHostException {
+        if (!delegateEnabled.get()) {
+            return fallback.lookupByAddress(addr);
+        }
+
+        try {
+            return delegate.lookupByAddress(addr);
+        } catch (UnknownHostException e) {
+            if (fallback != null) {
+                return fallback.lookupByAddress(addr);
+            }
+            throw e;
+        }
+    }
+}

docker-proxy-rule-core-jdk21/src/main/resources/META-INF/services/java.net.spi.InetAddressResolverProvider

@@ -0,0 +1 @@
+com.palantir.docker.proxy.DockerProxyManager$DockerProxyInetAddressResolverProvider

docker-proxy-rule-core-jdk21/src/test/java/com/palantir/docker/proxy/DockerContainerInfoUtilsTest.java

@@ -0,0 +1,56 @@
+/*
+ * (c) Copyright 2019 Palantir Technologies Inc. All rights reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.palantir.docker.proxy;
+
+import static com.palantir.docker.proxy.DockerContainerInfoUtils.IP_FORMAT_STRING;
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.mockito.ArgumentMatchers.any;
+import static org.mockito.ArgumentMatchers.anyLong;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.when;
+
+import com.palantir.docker.compose.execution.DockerExecutable;
+import java.io.ByteArrayInputStream;
+import java.io.IOException;
+import java.io.InputStream;
+import java.nio.charset.StandardCharsets;
+import java.util.Optional;
+import java.util.concurrent.TimeUnit;
+import org.junit.Test;
+
+public class DockerContainerInfoUtilsTest {
+    private static final String CONTAINER_ID = "container-id";
+
+    private final Process response = mock(Process.class);
+    private final DockerExecutable dockerExecutable = mock(DockerExecutable.class);
+
+    @Test
+    public void getContainerIpFromIdDoesNotThrowWhenContainerIsStopped() throws IOException, InterruptedException {
+        when(response.getInputStream()).thenReturn(getDockerOutputForStoppedContainer());
+        when(response.waitFor(anyLong(), any(TimeUnit.class))).thenReturn(true);
+        when(response.exitValue()).thenReturn(0);
+        when(dockerExecutable.execute("inspect", "--format", IP_FORMAT_STRING, CONTAINER_ID))
+                .thenReturn(response);
+
+        Optional<String> ip = DockerContainerInfoUtils.getContainerIpFromId(dockerExecutable, CONTAINER_ID);
+        assertThat(ip).isNotPresent();
+    }
+
+    private static InputStream getDockerOutputForStoppedContainer() {
+        return new ByteArrayInputStream("\n".getBytes(StandardCharsets.UTF_8));
+    }
+}

docker-proxy-rule-core-jdk21/src/test/java/com/palantir/docker/proxy/DockerNameServiceTest.java

@@ -0,0 +1,107 @@
+/*
+ * (c) Copyright 2017 Palantir Technologies Inc. All rights reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.palantir.docker.proxy;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.times;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.when;
+
+import com.google.common.net.InetAddresses;
+import java.net.InetAddress;
+import java.net.UnknownHostException;
+import java.util.Optional;
+import org.junit.Test;
+
+public class DockerNameServiceTest {
+    private static final String HOST_NAME = "host";
+    private static final String HOST_IP = "172.0.2.5";
+    private static final InetAddress HOST_IP_INET = InetAddresses.forString("172.0.2.5");
+
+    private final DockerContainerInfo containerInfo = mock(DockerContainerInfo.class);
+    private final DockerNameService dockerNameService = new DockerNameService(containerInfo);
+
+    @Test
+    public void shouldReturnIpOfHost() throws UnknownHostException {
+        when(containerInfo.getIpForHost(HOST_NAME)).thenReturn(Optional.of(HOST_IP));
+
+        InetAddress[] hostAddresses = dockerNameService.lookupAllHostAddr(HOST_NAME);
+
+        assertThat(hostAddresses).containsExactly(HOST_IP_INET);
+    }
+
+    @Test
+    public void shouldOnlyQueryTheSupplierOncePerLookupCall() throws UnknownHostException {
+        when(containerInfo.getIpForHost(HOST_NAME)).thenReturn(Optional.of(HOST_IP));
+
+        dockerNameService.lookupAllHostAddr(HOST_NAME);
+
+        verify(containerInfo, times(1)).getIpForHost(HOST_NAME);
+    }
+
+    @Test
+    public void shouldGetIpOfHostFromSupplierEveryTime() throws UnknownHostException {
+        when(containerInfo.getIpForHost(HOST_NAME)).thenReturn(Optional.of(HOST_IP));
+
+        dockerNameService.lookupAllHostAddr(HOST_NAME);
+        dockerNameService.lookupAllHostAddr(HOST_NAME);
+
+        verify(containerInfo, times(2)).getIpForHost(HOST_NAME);
+    }
+
+    @Test(expected = UnknownHostException.class)
+    public void shouldThrowUnknownHostExceptionWhenNoIpForHost() throws UnknownHostException {
+        when(containerInfo.getIpForHost(HOST_NAME)).thenReturn(Optional.empty());
+
+        dockerNameService.lookupAllHostAddr(HOST_NAME);
+    }
+
+    @Test
+    public void shouldGetHostFromIp() throws UnknownHostException {
+        when(containerInfo.getHostForIp(HOST_IP)).thenReturn(Optional.of(HOST_NAME));
+
+        String host = dockerNameService.getHostByAddr(HOST_IP_INET.getAddress());
+
+        assertThat(host).isEqualTo(HOST_NAME);
+    }
+
+    @Test
+    public void shouldOnlyQueryTheSupplierOncePerHostByAddrCall() throws UnknownHostException {
+        when(containerInfo.getHostForIp(HOST_IP)).thenReturn(Optional.of(HOST_NAME));
+
+        dockerNameService.getHostByAddr(HOST_IP_INET.getAddress());
+
+        verify(containerInfo, times(1)).getHostForIp(HOST_IP);
+    }
+
+    @Test
+    public void shouldGetHostOfIpFromSupplierEveryTime() throws UnknownHostException {
+        when(containerInfo.getHostForIp(HOST_IP)).thenReturn(Optional.of(HOST_NAME));
+
+        dockerNameService.getHostByAddr(HOST_IP_INET.getAddress());
+        dockerNameService.getHostByAddr(HOST_IP_INET.getAddress());
+
+        verify(containerInfo, times(2)).getHostForIp(HOST_IP);
+    }
+
+    @Test(expected = UnknownHostException.class)
+    public void shouldThrowUnknownHostExceptionWhenNoHostForIp() throws UnknownHostException {
+        when(containerInfo.getHostForIp(HOST_IP)).thenReturn(Optional.empty());
+
+        dockerNameService.getHostByAddr(HOST_IP_INET.getAddress());
+    }
+}