Allow external uri to be configurable for components that support server functionality.

SE nodes might be behind some sort of proxy exposed to hub on a
different hostname(/ip) and/or port than component would by default
report themselves (e.g.: hub and nodes are in different k8s clusters
 and services are exposed via node ports).

Fixes #12491

Author: utamas

java/src/org/openqa/selenium/grid/server/BaseServerFlags.java

@@ -33,6 +33,14 @@ public class BaseServerFlags implements HasRoles {
 
   private static final String SERVER_SECTION = "server";
 
+  @Parameter(
+      names = {"--external-uri"},
+      description = "External URI where component is generally available. " +
+        "Useful on complex network topologies when components are on different networks " +
+        "and proxy servers are involved.")
+  @ConfigValue(section = SERVER_SECTION, name = "external-uri", example = "http://10.0.1.1:33333")
+  private String externalUri;
+
   @Parameter(
       names = {"--host"},
       description = "Server IP or hostname: usually determined automatically.")

java/src/org/openqa/selenium/grid/server/BaseServerOptions.java

@@ -84,28 +84,38 @@ public int getMaxServerThreads() {
 
   @ManagedAttribute(name = "Uri")
   public URI getExternalUri() {
-    // Assume the host given is addressable if it's been set
-    String host =
-        getHostname()
+    return config.get(SERVER_SECTION, "external-uri")
+      .map(url -> {
+        try {
+          return new URI(url);
+        } catch (URISyntaxException e) {
+          throw new RuntimeException("Supplied external URI is invalid: " + e.getMessage(), e);
+        }
+      })
+      .orElseGet(() -> {
+        // Assume the host given is addressable if it's been set
+        String host =
+          getHostname()
             .orElseGet(
-                () -> {
-                  try {
-                    return new NetworkUtils().getNonLoopbackAddressOfThisMachine();
-                  } catch (WebDriverException e) {
-                    String name = HostIdentifier.getHostName();
-                    LOG.info("No network connection, guessing name: " + name);
-                    return name;
-                  }
-                });
-
-    int port = getPort();
-
-    try {
-      return new URI(
-          (isSecure() || isSelfSigned()) ? "https" : "http", null, host, port, null, null, null);
-    } catch (URISyntaxException e) {
-      throw new ConfigException("Cannot determine external URI: " + e.getMessage());
-    }
+              () -> {
+                try {
+                  return new NetworkUtils().getNonLoopbackAddressOfThisMachine();
+                } catch (WebDriverException e) {
+                  String name = HostIdentifier.getHostName();
+                  LOG.info("No network connection, guessing name: " + name);
+                  return name;
+                }
+              });
+
+        int port = getPort();
+
+        try {
+          return new URI(
+            (isSecure() || isSelfSigned()) ? "https" : "http", null, host, port, null, null, null);
+        } catch (URISyntaxException e) {
+          throw new ConfigException("Cannot determine external URI: " + e.getMessage());
+        }
+      });
   }
 
   public boolean getAllowCORS() {

java/test/org/openqa/selenium/grid/server/BaseServerOptionsTest.java

@@ -18,7 +18,10 @@
 package org.openqa.selenium.grid.server;
 
 import static org.assertj.core.api.Assertions.assertThat;
+import static org.junit.jupiter.api.Assertions.assertThrows;
 
+import java.net.URI;
+import java.net.URISyntaxException;
 import java.util.Map;
 import org.junit.jupiter.api.Test;
 import org.openqa.selenium.grid.config.MapConfig;
@@ -43,4 +46,43 @@ void serverConfigBindsToHostByDefault() {
 
     assertThat(options.getBindHost()).isEqualTo(true);
   }
+
+  @Test
+  void externalUriFailsForNonUriStrings() {
+    BaseServerOptions options =
+      new BaseServerOptions(new MapConfig(Map.of("server", Map.of("external-uri", "not a uri"))));
+
+    Exception exception = assertThrows(RuntimeException.class, () -> {
+      options.getExternalUri();
+    });
+
+    assertThat(exception.getMessage()).as("External URI must be parseable as URI.").isEqualTo("Supplied external URI is invalid: Illegal character in path at index 3: not a uri");
+  }
+
+  @Test
+  void externalUriTakesPriorityOverDefaults() throws URISyntaxException {
+    URI expected = new URI("http://10.0.1.1:33333");
+
+    BaseServerOptions options =
+      new BaseServerOptions(new MapConfig(Map.of("server", Map.of(
+        "external-uri", expected.toString(),
+        "host", "localhost",
+        "port", 5555
+      ))));
+
+    assertThat(options.getExternalUri()).isEqualTo(expected);
+  }
+
+  @Test
+  void externalUriDefaultsToValueDerivedFromHostnameAndPortWhenNotDefined() throws URISyntaxException {
+    URI expected = new URI("http://localhost:5555");
+
+    BaseServerOptions options =
+      new BaseServerOptions(new MapConfig(Map.of("server", Map.of(
+        "host", expected.getHost(),
+        "port", expected.getPort()
+      ))));
+
+    assertThat(options.getExternalUri()).isEqualTo(expected);
+  }
 }