Implement configuration-based SOCKS proxy support

changelog/@unreleased/pr-1428.v2.yml

@@ -0,0 +1,5 @@
+type: improvement
+improvement:
+  description: Implement configuration-based SOCKS proxy support
+  links:
+  - https://github.com/palantir/dialogue/pull/1428

dialogue-apache-hc5-client/src/main/java/com/palantir/dialogue/hc5/ApacheHttpClientChannels.java

@@ -47,6 +47,7 @@
 import java.net.MalformedURLException;
 import java.net.Proxy;
 import java.net.Socket;
+import java.net.URI;
 import java.net.URL;
 import java.time.Duration;
 import java.util.ArrayList;
@@ -477,7 +478,7 @@ public CloseableClient build() {
 
             Timeout handshakeTimeout = getHandshakeTimeout(connectTimeout, socketTimeout, name);
 
-            InetSocketAddress socksProxyAddress = getSocksProxyAddress();
+            InetSocketAddress socksProxyAddress = getSocksProxyAddress(conf);
             SSLSocketFactory rawSocketFactory = conf.sslSocketFactory();
             SSLConnectionSocketFactory sslSocketFactory =
                     new SSLConnectionSocketFactory(
@@ -592,6 +593,34 @@ private static InetSocketAddress getSocksProxyAddress() {
         return InetSocketAddress.createUnresolved(hostAndPort.getHost(), hostAndPort.getPort());
     }
 
+    @Nullable
+    private static InetSocketAddress getSocksProxyAddress(ClientConfiguration clientConfiguration) {
+        // This is a roundabout way to extract proxy information. SOCKS proxies are configured at
+        // a different stage from HTTP proxies, so we must search for any socks proxy that the
+        // ProxySelector can provide. 'selector.select(null)' could work to validate no real work
+        // is being done, but I think the 127.0.0.1 lookup should be safer.
+        // Ideally we could pass along the original ServiceConfigurationBlock (if it exists) which
+        // provides a more precise description of this data.
+        try {
+            InetSocketAddress address = clientConfiguration.proxy().select(URI.create("127.0.0.1")).stream()
+                    .filter(proxy -> proxy.type() == Proxy.Type.SOCKS)
+                    .map(Proxy::address)
+                    .filter(InetSocketAddress.class::isInstance)
+                    .map(InetSocketAddress.class::cast)
+                    .findFirst()
+                    .orElseGet(ApacheHttpClientChannels::getSocksProxyAddress);
+            if (address != null) {
+                log.debug("Found SOCKS proxy address", UnsafeArg.of("address", address));
+            } else {
+                log.debug("No SOCKS proxy found");
+            }
+            return address;
+        } catch (RuntimeException e) {
+            log.debug("Failed to find a SOCKS proxy", e);
+            return null;
+        }
+    }
+
     private static Timeout getSocketTimeout(ClientConfiguration conf, String clientName) {
         long socketTimeoutMillis = conf.readTimeout().toMillis();
         if (conf.readTimeout().toMillis() != conf.writeTimeout().toMillis()) {

dialogue-apache-hc5-client/src/test/java/com/palantir/dialogue/hc5/SocksProxyManualTest.java

@@ -19,7 +19,10 @@
 import static org.assertj.core.api.Assertions.assertThat;
 
 import com.google.common.util.concurrent.ListenableFuture;
+import com.palantir.conjure.java.api.config.service.ProxyConfiguration;
+import com.palantir.conjure.java.api.config.service.ServiceConfiguration;
 import com.palantir.conjure.java.client.config.ClientConfiguration;
+import com.palantir.conjure.java.client.config.ClientConfigurations;
 import com.palantir.conjure.java.config.ssl.SslSocketFactories;
 import com.palantir.dialogue.Channel;
 import com.palantir.dialogue.Request;
@@ -39,16 +42,16 @@
  */
 final class SocksProxyManualTest {
 
+    //    @org.junit.jupiter.api.Test
     void testTls() throws Exception {
         // ssh -D 8081 -v -N localhost
-        System.setProperty("dialogue.experimental.socks5.proxy", "127.0.0.1:8081");
         SSLContext context = SslSocketFactories.createSslContext(TestConfigurations.SSL_CONFIG);
         Undertow undertow = Undertow.builder()
                 .addHttpsListener(8080, null, context, new ResponseCodeHandler(204))
                 .build();
         undertow.start();
         try {
-            ClientConfiguration configuration = TestConfigurations.create("https://localhost:" + 8080);
+            ClientConfiguration configuration = withSocks("https://localhost:" + 8080, "127.0.0.1:8081");
             Channel channel = ApacheHttpClientChannels.create(configuration, "test");
             ListenableFuture<Response> future =
                     channel.execute(TestEndpoint.GET, Request.builder().build());
@@ -60,15 +63,15 @@ void testTls() throws Exception {
         }
     }
 
+    //    @org.junit.jupiter.api.Test
     void testPlain() throws Exception {
         // ssh -D 8081 -v -N localhost
-        System.setProperty("dialogue.experimental.socks5.proxy", "127.0.0.1:8081");
         Undertow undertow = Undertow.builder()
                 .addHttpListener(8080, null, new ResponseCodeHandler(204))
                 .build();
         undertow.start();
         try {
-            ClientConfiguration configuration = TestConfigurations.create("http://localhost:" + 8080);
+            ClientConfiguration configuration = withSocks("http://localhost:" + 8080, "127.0.0.1:8081");
             Channel channel = ApacheHttpClientChannels.create(configuration, "test");
             ListenableFuture<Response> future =
                     channel.execute(TestEndpoint.GET, Request.builder().build());
@@ -79,4 +82,16 @@ void testPlain() throws Exception {
             undertow.stop();
         }
     }
+
+    private static ClientConfiguration withSocks(String target, String socksAddress) {
+        return ClientConfiguration.builder()
+                .from(ClientConfigurations.of(ServiceConfiguration.builder()
+                        .addUris(target)
+                        .security(TestConfigurations.SSL_CONFIG)
+                        .maxNumRetries(0)
+                        .proxy(ProxyConfiguration.socks(socksAddress))
+                        .build()))
+                .userAgent(TestConfigurations.AGENT)
+                .build();
+    }
 }