Add slotMatcher parameter to node

 and where DefaultSlotMatcher is used without alternatives

java/src/org/openqa/selenium/grid/commands/Hub.java

@@ -163,7 +163,8 @@ protected Handlers createHandlers(Config config) {
             distributorOptions.getHealthCheckInterval(),
             distributorOptions.shouldRejectUnsupportedCaps(),
             newSessionRequestOptions.getSessionRequestRetryInterval(),
-            distributorOptions.getNewSessionThreadPoolSize());
+            distributorOptions.getNewSessionThreadPoolSize(),
+            distributorOptions.getSlotMatcher());
     handler.addHandler(distributor);
 
     Router router = new Router(tracer, clientFactory, sessions, queue, distributor);

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

@@ -167,7 +167,8 @@ protected Handlers createHandlers(Config config) {
             distributorOptions.getHealthCheckInterval(),
             distributorOptions.shouldRejectUnsupportedCaps(),
             newSessionRequestOptions.getSessionRequestRetryInterval(),
-            distributorOptions.getNewSessionThreadPoolSize());
+            distributorOptions.getNewSessionThreadPoolSize(),
+            distributorOptions.getSlotMatcher());
     combinedHandler.addHandler(distributor);
 
     Routable router =

java/src/org/openqa/selenium/grid/data/Slot.java

@@ -28,6 +28,7 @@
 import org.openqa.selenium.ImmutableCapabilities;
 import org.openqa.selenium.internal.Require;
 import org.openqa.selenium.json.JsonInput;
+import org.openqa.selenium.grid.data.SlotMatcher;
 
 public class Slot implements Serializable {
 
@@ -37,12 +38,12 @@ public class Slot implements Serializable {
   private final Instant lastStarted;
   private final SlotMatcher slotMatcher;
 
-  public Slot(SlotId id, Capabilities stereotype, Instant lastStarted, Session session) {
+  public Slot(SlotId id, Capabilities stereotype, Instant lastStarted, Session session, SlotMatcher slotMatcher) {
     this.id = Require.nonNull("Slot ID", id);
     this.stereotype = ImmutableCapabilities.copyOf(Require.nonNull("Stereotype", stereotype));
     this.lastStarted = Require.nonNull("Last started", lastStarted);
     this.session = session;
-    this.slotMatcher = new DefaultSlotMatcher();
+    this.slotMatcher = slotMatcher;
   }
 
   private static Slot fromJson(JsonInput input) {
@@ -78,7 +79,7 @@ private static Slot fromJson(JsonInput input) {
     }
     input.endObject();
 
-    return new Slot(id, stereotype, lastStarted, session);
+    return new Slot(id, stereotype, lastStarted, session, new DefaultSlotMatcher());
   }
 
   private Map<String, Object> toJson() {

java/src/org/openqa/selenium/grid/distributor/GridModel.java

@@ -47,6 +47,8 @@
 import org.openqa.selenium.grid.data.SessionClosedEvent;
 import org.openqa.selenium.grid.data.Slot;
 import org.openqa.selenium.grid.data.SlotId;
+import org.openqa.selenium.grid.data.SlotMatcher;
+import org.openqa.selenium.grid.data.DefaultSlotMatcher;
 import org.openqa.selenium.grid.server.EventBusOptions;
 import org.openqa.selenium.internal.Debug;
 import org.openqa.selenium.internal.Require;
@@ -65,18 +67,22 @@ public class GridModel {
   private final Map<NodeId, Instant> nodePurgeTimes = new ConcurrentHashMap<>();
   private final Map<NodeId, Integer> nodeHealthCount = new ConcurrentHashMap<>();
   private final EventBus events;
+  private final SlotMatcher slotMatcher;
 
-  public GridModel(EventBus events) {
+  public GridModel(EventBus events, SlotMatcher slotMatcher) {
     this.events = Require.nonNull("Event bus", events);
+    this.slotMatcher = Require.nonNull("Slot matcher", slotMatcher);
 
     this.events.addListener(NodeDrainStarted.listener(nodeId -> setAvailability(nodeId, DRAINING)));
     this.events.addListener(SessionClosedEvent.listener(this::release));
   }
 
   public static GridModel create(Config config) {
     EventBus bus = new EventBusOptions(config).getEventBus();
+    //SlotMatcher slotMatcher = new DistributorOptions(config).getSlotMatcher();
+    SlotMatcher slotMatcher = new DefaultSlotMatcher();
 
-    return new GridModel(bus);
+    return new GridModel(bus, slotMatcher);
   }
 
   public void add(NodeStatus node) {
@@ -381,7 +387,7 @@ public void release(SessionId id) {
 
           if (id.equals(slot.getSession().getId())) {
             Slot released =
-                new Slot(slot.getId(), slot.getStereotype(), slot.getLastStarted(), null);
+                new Slot(slot.getId(), slot.getStereotype(), slot.getLastStarted(), null, slotMatcher);
             amend(node.getAvailability(), node, released);
             return;
           }
@@ -405,7 +411,8 @@ public void reserve(NodeStatus status, Slot slot) {
                 status.getExternalUri(),
                 slot.getStereotype(),
                 slot.getStereotype(),
-                now));
+                now),
+            slotMatcher);
 
     amend(UP, status, reserved);
   }
@@ -451,7 +458,8 @@ public void setSession(SlotId slotId, Session session) {
               slot.getId(),
               slot.getStereotype(),
               session == null ? slot.getLastStarted() : session.getStartTime(),
-              session);
+              session,
+              slotMatcher);
 
       amend(node.getAvailability(), node, updated);
     } finally {

java/src/org/openqa/selenium/grid/distributor/local/LocalDistributor.java

@@ -80,6 +80,7 @@
 import org.openqa.selenium.grid.data.SessionRequestCapability;
 import org.openqa.selenium.grid.data.Slot;
 import org.openqa.selenium.grid.data.SlotId;
+import org.openqa.selenium.grid.data.SlotMatcher;
 import org.openqa.selenium.grid.data.TraceSessionRequest;
 import org.openqa.selenium.grid.distributor.Distributor;
 import org.openqa.selenium.grid.distributor.GridModel;
@@ -179,7 +180,8 @@ public LocalDistributor(
       Duration healthcheckInterval,
       boolean rejectUnsupportedCaps,
       Duration sessionRequestRetryInterval,
-      int newSessionThreadPoolSize) {
+      int newSessionThreadPoolSize,
+      SlotMatcher slotMatcher) {
     super(tracer, clientFactory, registrationSecret);
     this.tracer = Require.nonNull("Tracer", tracer);
     this.bus = Require.nonNull("Event bus", bus);
@@ -189,7 +191,7 @@ public LocalDistributor(
     this.slotSelector = Require.nonNull("Slot selector", slotSelector);
     this.registrationSecret = Require.nonNull("Registration secret", registrationSecret);
     this.healthcheckInterval = Require.nonNull("Health check interval", healthcheckInterval);
-    this.model = new GridModel(bus);
+    this.model = new GridModel(bus, slotMatcher);
     this.nodes = new ConcurrentHashMap<>();
     this.rejectUnsupportedCaps = rejectUnsupportedCaps;
     Require.nonNull("Session request interval", sessionRequestRetryInterval);
@@ -263,7 +265,8 @@ public static Distributor create(Config config) {
         distributorOptions.getHealthCheckInterval(),
         distributorOptions.shouldRejectUnsupportedCaps(),
         newSessionQueueOptions.getSessionRequestRetryInterval(),
-        distributorOptions.getNewSessionThreadPoolSize());
+        distributorOptions.getNewSessionThreadPoolSize(),
+        distributorOptions.getSlotMatcher());
   }
 
   @Override

java/src/org/openqa/selenium/grid/node/config/NodeFlags.java

@@ -31,6 +31,7 @@
 import static org.openqa.selenium.grid.node.config.NodeOptions.DEFAULT_SESSION_TIMEOUT;
 import static org.openqa.selenium.grid.node.config.NodeOptions.DEFAULT_USE_SELENIUM_MANAGER;
 import static org.openqa.selenium.grid.node.config.NodeOptions.DEFAULT_VNC_ENV_VAR;
+import static org.openqa.selenium.grid.node.config.NodeOptions.DEFAULT_SLOT_MATCHER;
 import static org.openqa.selenium.grid.node.config.NodeOptions.NODE_SECTION;
 import static org.openqa.selenium.grid.node.config.NodeOptions.OVERRIDE_MAX_SESSIONS;
 
@@ -68,6 +69,15 @@ public class NodeFlags implements HasRoles {
   @ConfigValue(section = NODE_SECTION, name = "override-max-sessions", example = "false")
   public Boolean overrideMaxSessions = OVERRIDE_MAX_SESSIONS;
 
+  @Parameter(
+      names = {"--slot-matcher"},
+      description =
+          "Full classname of non-default slot matcher to use. This is used to determine whether a"
+              + " Node can support a particular session. The class provided here should be the same as the one"
+              + " used for distributor options")
+  @ConfigValue(section = NODE_SECTION, name = "slot-matcher", example = DEFAULT_SLOT_MATCHER)
+  private String slotMatcher = DEFAULT_SLOT_MATCHER;
+
   @Parameter(
       names = {"--session-timeout"},
       description =

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

@@ -55,6 +55,7 @@
 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.data.SlotMatcher;
 import org.openqa.selenium.internal.Require;
 import org.openqa.selenium.json.Json;
 import org.openqa.selenium.json.JsonOutput;
@@ -81,6 +82,8 @@ public class NodeOptions {
   static final int DEFAULT_REGISTER_PERIOD = 120;
   static final String DEFAULT_NODE_IMPLEMENTATION =
       "org.openqa.selenium.grid.node.local.LocalNodeFactory";
+  static final String DEFAULT_SLOT_MATCHER = 
+      "org.openqa.selenium.grid.data.DefaultSlotMatcher";
   private static final Logger LOG = Logger.getLogger(NodeOptions.class.getName());
   private static final Json JSON = new Json();
   private static final Platform CURRENT_PLATFORM = Platform.getCurrent();
@@ -170,6 +173,11 @@ public Duration getRegisterCycle() {
     return Duration.ofSeconds(seconds);
   }
 
+  public SlotMatcher getSlotMatcher() {
+    return config.getClass(
+        NODE_SECTION, "slot-matcher", SlotMatcher.class, DEFAULT_SLOT_MATCHER);
+  }
+
   public Duration getRegisterPeriod() {
     // If the user sets 0 or less, we default to 1s.
     int seconds =

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

@@ -181,7 +181,8 @@ public Map<Capabilities, Collection<SessionFactory>> getDockerSessionFactories(
                     videoImage,
                     assetsPath,
                     networkName,
-                    info.isPresent()));
+                    info.isPresent(),
+                    options.getSlotMatcher()));
           }
           LOG.info(
               String.format(

java/src/org/openqa/selenium/grid/node/docker/DockerSessionFactory.java

@@ -116,7 +116,8 @@ public DockerSessionFactory(
       Image videoImage,
       DockerAssetsPath assetsPath,
       String networkName,
-      boolean runningInDocker) {
+      boolean runningInDocker,
+      SlotMatcher slotMatcher) {
     this.tracer = Require.nonNull("Tracer", tracer);
     this.clientFactory = Require.nonNull("HTTP client", clientFactory);
     this.sessionTimeout = Require.nonNull("Session timeout", sessionTimeout);
@@ -129,7 +130,7 @@ public DockerSessionFactory(
     this.videoImage = videoImage;
     this.assetsPath = assetsPath;
     this.runningInDocker = runningInDocker;
-    this.slotMatcher = new DefaultSlotMatcher();
+    this.slotMatcher = slotMatcher;
   }
 
   @Override

java/src/org/openqa/selenium/grid/node/local/LocalNode.java

@@ -82,6 +82,8 @@
 import org.openqa.selenium.grid.data.Session;
 import org.openqa.selenium.grid.data.Slot;
 import org.openqa.selenium.grid.data.SlotId;
+import org.openqa.selenium.grid.data.SlotMatcher;
+import org.openqa.selenium.grid.data.DefaultSlotMatcher;
 import org.openqa.selenium.grid.jmx.JMXHelper;
 import org.openqa.selenium.grid.jmx.ManagedAttribute;
 import org.openqa.selenium.grid.jmx.ManagedService;
@@ -119,6 +121,7 @@ public class LocalNode extends Node {
   private static final Logger LOG = Logger.getLogger(LocalNode.class.getName());
 
   private final EventBus bus;
+  private final SlotMatcher slotMatcher;
   private final URI externalUri;
   private final URI gridUri;
   private final Duration heartbeatPeriod;
@@ -153,7 +156,8 @@ protected LocalNode(
       Duration heartbeatPeriod,
       List<SessionSlot> factories,
       Secret registrationSecret,
-      boolean managedDownloadsEnabled) {
+      boolean managedDownloadsEnabled,
+      SlotMatcher slotMatcher) {
     super(tracer, new NodeId(UUID.randomUUID()), uri, registrationSecret);
 
     this.bus = Require.nonNull("Event bus", bus);
@@ -171,6 +175,7 @@ protected LocalNode(
     this.cdpEnabled = cdpEnabled;
     this.bidiEnabled = bidiEnabled;
     this.managedDownloadsEnabled = managedDownloadsEnabled;
+    this.slotMatcher = slotMatcher;
 
     this.healthCheck =
         healthCheck == null
@@ -855,7 +860,8 @@ public NodeStatus getStatus() {
                       new SlotId(getId(), slot.getId()),
                       slot.getStereotype(),
                       lastStarted,
-                      session);
+                      session,
+                      slotMatcher);
                 })
             .collect(toImmutableSet());
 
@@ -940,6 +946,7 @@ public static class Builder {
     private HealthCheck healthCheck;
     private Duration heartbeatPeriod = Duration.ofSeconds(NodeOptions.DEFAULT_HEARTBEAT_PERIOD);
     private boolean managedDownloadsEnabled = false;
+    private SlotMatcher slotMatcher = new DefaultSlotMatcher();
 
     private Builder(Tracer tracer, EventBus bus, URI uri, URI gridUri, Secret registrationSecret) {
       this.tracer = Require.nonNull("Tracer", tracer);
@@ -994,6 +1001,11 @@ public Builder enableManagedDownloads(boolean enable) {
       return this;
     }
 
+    public Builder slotMatcher(SlotMatcher slotMatcher) {
+      this.slotMatcher = slotMatcher;
+      return this;
+    }
+
     public LocalNode build() {
       return new LocalNode(
           tracer,
@@ -1010,7 +1022,8 @@ public LocalNode build() {
           heartbeatPeriod,
           factories.build(),
           registrationSecret,
-          managedDownloadsEnabled);
+          managedDownloadsEnabled,
+          slotMatcher);
     }
 
     public Advanced advanced() {

java/src/org/openqa/selenium/grid/node/local/LocalNodeFactory.java

@@ -71,14 +71,15 @@ public static Node create(Config config) {
             .enableCdp(nodeOptions.isCdpEnabled())
             .enableBiDi(nodeOptions.isBiDiEnabled())
             .enableManagedDownloads(nodeOptions.isManagedDownloadsEnabled())
-            .heartbeatPeriod(nodeOptions.getHeartbeatPeriod());
+            .heartbeatPeriod(nodeOptions.getHeartbeatPeriod())
+            .slotMatcher(nodeOptions.getSlotMatcher());
 
     List<DriverService.Builder<?, ?>> builders = new ArrayList<>();
     ServiceLoader.load(DriverService.Builder.class).forEach(builders::add);
 
     nodeOptions
         .getSessionFactories(
-            caps -> createSessionFactory(tracer, clientFactory, sessionTimeout, builders, caps))
+            caps -> createSessionFactory(tracer, clientFactory, sessionTimeout, builders, caps, nodeOptions.getSlotMatcher()))
         .forEach((caps, factories) -> factories.forEach(factory -> builder.add(caps, factory)));
 
     if (config.getAll("docker", "configs").isPresent()) {
@@ -101,9 +102,9 @@ private static Collection<SessionFactory> createSessionFactory(
       HttpClient.Factory clientFactory,
       Duration sessionTimeout,
       List<DriverService.Builder<?, ?>> builders,
-      Capabilities stereotype) {
+      Capabilities stereotype,
+      SlotMatcher slotMatcher) {
     ImmutableList.Builder<SessionFactory> toReturn = ImmutableList.builder();
-    SlotMatcher slotMatcher = new DefaultSlotMatcher();
     String webDriverExecutablePath =
         String.valueOf(stereotype.asMap().getOrDefault("se:webDriverExecutable", ""));