[grid] Allow Node implementation to be pluggable

This uses the same mechanism as used by `EventBus` and
`SessionMap`. By default we use a local instance, but --- hey! ---
anything is possible.

java/server/src/org/openqa/selenium/grid/commands/Standalone.java

@@ -28,13 +28,11 @@
 import org.openqa.selenium.grid.config.Role;
 import org.openqa.selenium.grid.distributor.Distributor;
 import org.openqa.selenium.grid.distributor.local.LocalDistributor;
-import org.openqa.selenium.grid.docker.DockerOptions;
 import org.openqa.selenium.grid.graphql.GraphqlHandler;
 import org.openqa.selenium.grid.log.LoggingOptions;
 import org.openqa.selenium.grid.node.Node;
 import org.openqa.selenium.grid.node.ProxyNodeCdp;
 import org.openqa.selenium.grid.node.config.NodeOptions;
-import org.openqa.selenium.grid.node.local.LocalNode;
 import org.openqa.selenium.grid.router.Router;
 import org.openqa.selenium.grid.server.BaseServerOptions;
 import org.openqa.selenium.grid.server.EventBusOptions;
@@ -148,18 +146,7 @@ protected void execute(Config config) {
       Route.post("/graphql").to(() -> graphqlHandler),
       Route.get("/readyz").to(() -> readinessCheck));
 
-    LocalNode.Builder nodeBuilder = LocalNode.builder(
-      tracer,
-      bus,
-      localhost,
-      localhost,
-      null)
-      .maximumConcurrentSessions(Runtime.getRuntime().availableProcessors() * 3);
-
-    new NodeOptions(config).configure(tracer, clientFactory, nodeBuilder);
-    new DockerOptions(config).configure(tracer, clientFactory, nodeBuilder);
-
-    Node node = nodeBuilder.build();
+    Node node = new NodeOptions(config).getNode();
     combinedHandler.addHandler(node);
     distributor.add(node);
 

java/server/src/org/openqa/selenium/grid/docker/BUILD.bazel

@@ -6,6 +6,7 @@ java_library(
     visibility = [
         "//java/server/src/org/openqa/selenium/grid/commands:__pkg__",
         "//java/server/src/org/openqa/selenium/grid/node/httpd:__pkg__",
+        "//java/server/src/org/openqa/selenium/grid/node/local:__pkg__",
     ],
     deps = [
         "//java:auto-service",
@@ -16,7 +17,6 @@ java_library(
         "//java/server/src/org/openqa/selenium/grid/config",
         "//java/server/src/org/openqa/selenium/grid/data",
         "//java/server/src/org/openqa/selenium/grid/node",
-        "//java/server/src/org/openqa/selenium/grid/node/local",
         artifact("com.beust:jcommander"),
         artifact("com.google.guava:guava"),
     ],

java/server/src/org/openqa/selenium/grid/docker/DockerOptions.java

@@ -18,6 +18,8 @@
 package org.openqa.selenium.grid.docker;
 
 import com.google.common.collect.HashMultimap;
+import com.google.common.collect.ImmutableMap;
+import com.google.common.collect.ImmutableMultimap;
 import com.google.common.collect.Multimap;
 import org.openqa.selenium.Capabilities;
 import org.openqa.selenium.Platform;
@@ -26,7 +28,7 @@
 import org.openqa.selenium.docker.Image;
 import org.openqa.selenium.grid.config.Config;
 import org.openqa.selenium.grid.config.ConfigException;
-import org.openqa.selenium.grid.node.local.LocalNode;
+import org.openqa.selenium.grid.node.SessionFactory;
 import org.openqa.selenium.internal.Require;
 import org.openqa.selenium.json.Json;
 import org.openqa.selenium.remote.http.ClientConfig;
@@ -36,7 +38,9 @@
 import java.net.URI;
 import java.net.URISyntaxException;
 import java.util.Arrays;
+import java.util.Collection;
 import java.util.List;
+import java.util.Map;
 import java.util.Optional;
 import java.util.concurrent.CompletableFuture;
 import java.util.concurrent.ExecutionException;
@@ -102,9 +106,12 @@ private boolean isEnabled(HttpClient.Factory clientFactory) {
     return new Docker(client).isSupported();
   }
 
-  public void configure(Tracer tracer, HttpClient.Factory clientFactory, LocalNode.Builder node) {
+  public Map<Capabilities, Collection<SessionFactory>> getDockerSessionFactories(
+    Tracer tracer,
+    HttpClient.Factory clientFactory) {
+
     if (!isEnabled(clientFactory)) {
-      return;
+      return ImmutableMap.of();
     }
 
     List<String> allConfigs = config.getAll(DOCKER_SECTION, "configs")
@@ -128,17 +135,19 @@ public void configure(Tracer tracer, HttpClient.Factory clientFactory, LocalNode
     loadImages(docker, kinds.keySet().toArray(new String[0]));
 
     int maxContainerCount = Runtime.getRuntime().availableProcessors();
+    ImmutableMultimap.Builder<Capabilities, SessionFactory> factories = ImmutableMultimap.builder();
     kinds.forEach((name, caps) -> {
       Image image = docker.getImage(name);
       for (int i = 0; i < maxContainerCount; i++) {
-        node.add(caps, new DockerSessionFactory(tracer, clientFactory, docker, image, caps));
+        factories.put(caps, new DockerSessionFactory(tracer, clientFactory, docker, image, caps));
       }
       LOG.info(String.format(
           "Mapping %s to docker image %s %d times",
           caps,
           name,
           maxContainerCount));
     });
+    return factories.build().asMap();
   }
 
   private void loadImages(Docker docker, String... imageNames) {

java/server/src/org/openqa/selenium/grid/node/config/BUILD.bazel

@@ -14,7 +14,6 @@ java_library(
         "//java/server/src/org/openqa/selenium/grid/config",
         "//java/server/src/org/openqa/selenium/grid/data",
         "//java/server/src/org/openqa/selenium/grid/node",
-        "//java/server/src/org/openqa/selenium/grid/node/local",
         artifact("com.google.guava:guava"),
     ],
 )

java/server/src/org/openqa/selenium/grid/node/config/NodeOptions.java

@@ -18,27 +18,30 @@
 package org.openqa.selenium.grid.node.config;
 
 import com.google.common.collect.HashMultimap;
+import com.google.common.collect.ImmutableMap;
+import com.google.common.collect.ImmutableMultimap;
+import com.google.common.collect.Multimap;
 import org.openqa.selenium.Capabilities;
 import org.openqa.selenium.WebDriverInfo;
 import org.openqa.selenium.grid.config.Config;
 import org.openqa.selenium.grid.config.ConfigException;
+import org.openqa.selenium.grid.node.Node;
 import org.openqa.selenium.grid.node.SessionFactory;
-import org.openqa.selenium.grid.node.local.LocalNode;
 import org.openqa.selenium.internal.Require;
 import org.openqa.selenium.json.Json;
 import org.openqa.selenium.json.JsonOutput;
-import org.openqa.selenium.remote.http.HttpClient;
 import org.openqa.selenium.remote.service.DriverService;
-import org.openqa.selenium.remote.tracing.Tracer;
 
 import java.net.URI;
 import java.net.URISyntaxException;
 import java.util.ArrayList;
 import java.util.Collection;
+import java.util.Comparator;
 import java.util.List;
 import java.util.Map;
 import java.util.Optional;
 import java.util.ServiceLoader;
+import java.util.function.Function;
 import java.util.logging.Logger;
 import java.util.stream.Collectors;
 import java.util.stream.StreamSupport;
@@ -47,6 +50,8 @@ public class NodeOptions {
 
   private static final Logger LOG = Logger.getLogger(NodeOptions.class.getName());
   private static final Json JSON = new Json();
+  private static final String DEFAULT_IMPL = "org.openqa.selenium.grid.node.local.LocalNodeFactory";
+
   private final Config config;
 
   public NodeOptions(Config config) {
@@ -63,80 +68,92 @@ public Optional<URI> getPublicGridUri() {
     });
   }
 
-  public void configure(Tracer tracer, HttpClient.Factory httpClientFactory, LocalNode.Builder node) {
+  public Node getNode() {
+    return config.getClass("node", "implementation", Node.class, DEFAULT_IMPL);
+  }
+
+  public Map<Capabilities, Collection<SessionFactory>> getSessionFactories(
+    /* Danger! Java stereotype ahead! */ Function<WebDriverInfo, Collection<SessionFactory>> factoryFactory) {
+
     int maxSessions = Math.min(
       config.getInt("node", "max-concurrent-sessions").orElse(Runtime.getRuntime().availableProcessors()),
       Runtime.getRuntime().availableProcessors());
 
-    Map<WebDriverInfo, Collection<SessionFactory>> allDrivers = discoverDrivers(tracer, httpClientFactory, maxSessions);
+    Map<WebDriverInfo, Collection<SessionFactory>> allDrivers = discoverDrivers(maxSessions, factoryFactory);
 
     // If drivers have been specified, use those.
     List<String> drivers = config.getAll("node", "drivers").orElse(new ArrayList<>()).stream()
       .map(String::toLowerCase)
       .collect(Collectors.toList());
 
+    ImmutableMultimap.Builder<Capabilities, SessionFactory> sessionFactories = ImmutableMultimap.builder();
+
     if (!drivers.isEmpty()) {
       allDrivers.entrySet().stream()
         .filter(entry -> drivers.contains(entry.getKey().getDisplayName().toLowerCase()))
+        .sorted(Comparator.comparing(entry -> entry.getKey().getDisplayName().toLowerCase()))
         .peek(this::report)
-        .forEach(entry -> entry.getValue().forEach(factory -> node.add(entry.getKey().getCanonicalCapabilities(), factory)));
+        .forEach(entry -> sessionFactories.putAll(entry.getKey().getCanonicalCapabilities(), entry.getValue()));
 
-      return;
+      return sessionFactories.build().asMap();
     }
 
     if (!config.getBool("node", "detect-drivers").orElse(false)) {
-      return;
+      return sessionFactories.build().asMap();
     }
 
     allDrivers.entrySet().stream()
       .peek(this::report)
-      .forEach(entry -> entry.getValue().forEach(factory -> node.add(entry.getKey().getCanonicalCapabilities(), factory)));
-  }
+      .forEach(entry -> sessionFactories.putAll(entry.getKey().getCanonicalCapabilities(), entry.getValue()));
 
-  private void report(Map.Entry<WebDriverInfo, Collection<SessionFactory>> entry) {
-    StringBuilder caps = new StringBuilder();
-    try (JsonOutput out = JSON.newOutput(caps)) {
-      out.setPrettyPrint(false);
-      out.write(entry.getKey().getCanonicalCapabilities());
-    }
-
-    LOG.info(String.format(
-      "Adding %s for %s %d times",
-      entry.getKey().getDisplayName(),
-      caps.toString().replaceAll("\\s+", " "),
-      entry.getValue().size()));
+    return sessionFactories.build().asMap();
   }
 
   private Map<WebDriverInfo, Collection<SessionFactory>> discoverDrivers(
-    Tracer tracer,
-    HttpClient.Factory clientFactory,
-    int maxSessions) {
+    int maxSessions,
+    Function<WebDriverInfo, Collection<SessionFactory>> factoryFactory) {
+
+    if (!config.getBool("node", "detect-drivers").orElse(false)) {
+      return ImmutableMap.of();
+    }
+
     // We don't expect duplicates, but they're fine
     List<WebDriverInfo> infos =
       StreamSupport.stream(ServiceLoader.load(WebDriverInfo.class).spliterator(), false)
         .filter(WebDriverInfo::isAvailable)
+        .sorted(Comparator.comparing(info -> info.getDisplayName().toLowerCase()))
         .collect(Collectors.toList());
 
     // Same
-    List<DriverService.Builder> builders = new ArrayList<>();
+    List<DriverService.Builder<?, ?>> builders = new ArrayList<>();
     ServiceLoader.load(DriverService.Builder.class).forEach(builders::add);
 
-    HashMultimap<WebDriverInfo, SessionFactory> toReturn = HashMultimap.create();
+    Multimap<WebDriverInfo, SessionFactory> toReturn = HashMultimap.create();
     infos.forEach(info -> {
       Capabilities caps = info.getCanonicalCapabilities();
       builders.stream()
         .filter(builder -> builder.score(caps) > 0)
         .forEach(builder -> {
           for (int i = 0; i < Math.min(info.getMaximumSimultaneousSessions(), maxSessions); i++) {
-
-            DriverService.Builder freePortBuilder = builder.usingAnyFreePort();
-            toReturn.put(info, new DriverServiceSessionFactory(
-              tracer,
-              clientFactory, c -> freePortBuilder.score(c) > 0,
-              freePortBuilder));
+            toReturn.putAll(info, factoryFactory.apply(info));
           }
         });
     });
+
     return toReturn.asMap();
   }
+
+  private void report(Map.Entry<WebDriverInfo, Collection<SessionFactory>> entry) {
+    StringBuilder caps = new StringBuilder();
+    try (JsonOutput out = JSON.newOutput(caps)) {
+      out.setPrettyPrint(false);
+      out.write(entry.getKey().getCanonicalCapabilities());
+    }
+
+    LOG.info(String.format(
+      "Adding %s for %s %d times",
+      entry.getKey().getDisplayName(),
+      caps.toString().replaceAll("\\s+", " "),
+      entry.getValue().size()));
+  }
 }

java/server/src/org/openqa/selenium/grid/node/httpd/BUILD.bazel

@@ -20,7 +20,6 @@ java_library(
         "//java/server/src/org/openqa/selenium/grid/log",
         "//java/server/src/org/openqa/selenium/grid/node",
         "//java/server/src/org/openqa/selenium/grid/node/config",
-        "//java/server/src/org/openqa/selenium/grid/node/local",
         "//java/server/src/org/openqa/selenium/grid/server",
         "//java/server/src/org/openqa/selenium/grid/web",
         "//java/server/src/org/openqa/selenium/netty/server",

java/server/src/org/openqa/selenium/grid/node/httpd/NodeServer.java

@@ -30,11 +30,10 @@
 import org.openqa.selenium.grid.config.Config;
 import org.openqa.selenium.grid.config.Role;
 import org.openqa.selenium.grid.data.NodeStatusEvent;
-import org.openqa.selenium.grid.docker.DockerOptions;
 import org.openqa.selenium.grid.log.LoggingOptions;
+import org.openqa.selenium.grid.node.Node;
 import org.openqa.selenium.grid.node.ProxyNodeCdp;
 import org.openqa.selenium.grid.node.config.NodeOptions;
-import org.openqa.selenium.grid.node.local.LocalNode;
 import org.openqa.selenium.grid.server.BaseServerOptions;
 import org.openqa.selenium.grid.server.EventBusOptions;
 import org.openqa.selenium.grid.server.NetworkOptions;
@@ -115,17 +114,7 @@ protected void execute(Config config) {
 
     NodeOptions nodeOptions = new NodeOptions(config);
 
-    LocalNode.Builder builder = LocalNode.builder(
-      tracer,
-      bus,
-      serverOptions.getExternalUri(),
-      nodeOptions.getPublicGridUri().orElseGet(serverOptions::getExternalUri),
-      serverOptions.getRegistrationSecret());
-
-    nodeOptions.configure(tracer, clientFactory, builder);
-    new DockerOptions(config).configure(tracer, clientFactory, builder);
-
-    LocalNode node = builder.build();
+    Node node = nodeOptions.getNode();
 
     HttpHandler readinessCheck = req -> {
       if (node.getStatus().hasCapacity()) {

java/server/src/org/openqa/selenium/grid/node/local/BUILD.bazel

@@ -16,8 +16,13 @@ java_library(
         "//java/server/src/org/openqa/selenium/concurrent",
         "//java/server/src/org/openqa/selenium/events",
         "//java/server/src/org/openqa/selenium/grid/component",
+        "//java/server/src/org/openqa/selenium/grid/config",
         "//java/server/src/org/openqa/selenium/grid/data",
+        "//java/server/src/org/openqa/selenium/grid/docker",
+        "//java/server/src/org/openqa/selenium/grid/log",
         "//java/server/src/org/openqa/selenium/grid/node",
+        "//java/server/src/org/openqa/selenium/grid/node/config",
+        "//java/server/src/org/openqa/selenium/grid/server",
         "//java/server/src/org/openqa/selenium/grid/web",
         artifact("com.google.guava:guava"),
     ],