Merge pull request #120 from DeepBlueRobotics/complete-workaround-for…

…-HALSimWS-SimDevice-deadlocks

Complete-workaround-for-HALSimWS-SimDevice-deadlocks

README.md

@@ -32,11 +32,24 @@ advantage of the WPILib's WebSockets server desktop simulation extension.
 ### Demo
 
  1. In VSCode run the `WPILib: Create a new project` command and create the example project.
- 1. Add the DeepBlueSim Gradle plugin to the `build.gradle` as described above.
- 1. In VSCode run the `WPILib: Simulate Robot Code on Desktop` command and select both
+ 2. Add the DeepBlueSim Gradle plugin to the `build.gradle` as described above.
+ 3. If you are not using [`lib199`](https://github.com/DeepBlueRobotics/lib199), add the following 2
+    lines to your robot's `simulationInit()` method (`lib199` handles this automatically):
+ ```java
+     @Override
+    public void simulationInit() {
+        // Regularly request a HALSimWS connection from the DeepBlueSim controller (if/when it is
+        // listening). To workaround https://github.com/wpilibsuite/allwpilib/issues/6842, this must
+        // be done *after* any SimDevices have been created.
+        var reqPublisher = NetworkTableInstance.getDefault()
+                .getStringTopic("/DeepBlueSim/Coordinator/request").publish();
+        addPeriodic(() -> reqPublisher.set("connectHALSimWS"), kDefaultPeriod);
+    }
+ ```
+ 4. In VSCode run the `WPILib: Simulate Robot Code on Desktop` command and select both
  `libhalsim_gui` and `libhalsim_ws_server` as the extensions to use.
- 1. Start Webots and open *your_example_project*`/Webots/worlds/DBSExample.wbt`
- 1. In the HALSim GUI, select `Autonomous` to see the robot drive forward for 2 seconds, or
+ 5. Start Webots and open *your_example_project*`/Webots/worlds/DBSExample.wbt`
+ 6. In the HALSim GUI, select `Autonomous` to see the robot drive forward for 2 seconds, or
  select `Teleop` and use the keyboard on joystick to drive the robot around.
 
 ## Details

example/build.gradle

@@ -2,7 +2,7 @@ plugins {
     id "java"
     id 'jvm-test-suite'
     id "edu.wpi.first.GradleRIO" version "2024.3.1"
-    id "org.carlmontrobotics.deepbluesim" version "2024.0.0"
+    id "org.carlmontrobotics.deepbluesim" version "unspecified"
 }
 
 java {

example/src/main/java/frc/robot/Robot.java

@@ -7,9 +7,11 @@
 
 package frc.robot;
 
-import edu.wpi.first.wpilibj.Joystick;
+import edu.wpi.first.networktables.NetworkTableInstance;
+import edu.wpi.first.wpilibj.GenericHID;
 import edu.wpi.first.wpilibj.TimedRobot;
 import edu.wpi.first.wpilibj.Timer;
+import edu.wpi.first.wpilibj.StadiaController.Axis;
 import edu.wpi.first.wpilibj.drive.DifferentialDrive;
 import edu.wpi.first.wpilibj.motorcontrol.PWMVictorSPX;
 import edu.wpi.first.wpilibj.motorcontrol.PWMMotorController;
@@ -22,7 +24,7 @@
  */
 public class Robot extends TimedRobot {
 
-    private final Joystick m_stick = new Joystick(0);
+    private final GenericHID m_controller = new GenericHID(0);
     private final Timer m_timer = new Timer();
     private DifferentialDrive m_robotDrive;
     private PWMMotorController m_leftMaster;
@@ -51,6 +53,19 @@ public void robotInit() {
         m_elevator = new PWMVictorSPX(4);
     }
 
+    /**
+     * This function is run when the robot is first started up in simulation.
+     */
+    @Override
+    public void simulationInit() {
+        // Regularly request a HALSimWS connection from the DeepBlueSim controller (if/when it is
+        // listening). To workaround https://github.com/wpilibsuite/allwpilib/issues/6842, this must
+        // be done *after* any SimDevices have been created.
+        var reqPublisher = NetworkTableInstance.getDefault()
+                .getStringTopic("/DeepBlueSim/Coordinator/request").publish();
+        addPeriodic(() -> reqPublisher.set("connectHALSimWS"), kDefaultPeriod);
+    }
+
     public void close() {
         System.out.println("Closing motors in Robot.close()");
         m_leftMaster.close();
@@ -94,7 +109,9 @@ public void teleopInit() {}
      */
     @Override
     public void teleopPeriodic() {
-        m_robotDrive.arcadeDrive(m_stick.getY(), m_stick.getX());
+        m_robotDrive.arcadeDrive(-m_controller.getRawAxis(Axis.kLeftY.value),
+                m_controller.getRawAxis(Axis.kLeftX.value));
+        m_elevator.set(-m_controller.getRawAxis(Axis.kRightY.value));
     }
 
     /**

plugin/controller/src/main/java/DeepBlueSim.java

@@ -24,7 +24,6 @@
 import org.carlmontrobotics.deepbluesim.Simulation;
 import org.carlmontrobotics.deepbluesim.WebotsSupervisor;
 import org.carlmontrobotics.wpiws.connection.RunningObject;
-import org.carlmontrobotics.wpiws.connection.WSConnection;
 
 // NOTE: Webots expects the controller class to *not* be in a package and have a name that matches
 // the name of the jar.
@@ -34,8 +33,6 @@ public class DeepBlueSim {
     // Webots/controllers/DeepBlueSim/logging.properties file so that ".level=FINE".
     private static Logger LOG = null;
 
-    private static RunningObject<WebSocketClient> wsConnection = null;
-
     private static void startNetworkTablesClient(NetworkTableInstance inst) {
         inst.startClient4("Webots controller");
         inst.setServer("localhost");
@@ -97,12 +94,7 @@ public void uncaughtException(Thread arg0, Throwable t) {
         }
 
         if (connectToRobotCode) {
-            WebotsSupervisor.init(robot, basicTimeStep, () -> {
-                if (wsConnection == null)
-                    return null;
-                else
-                    return wsConnection.object;
-            });
+            WebotsSupervisor.init(robot, basicTimeStep);
         }
 
         // Wait until startup has completed to ensure that the Webots simulator is
@@ -119,16 +111,6 @@ public void uncaughtException(Thread arg0, Throwable t) {
             // user does.
             robot.simulationSetMode(Supervisor.SIMULATION_MODE_PAUSE);
 
-            // Connect to the robot code on a separate thread. Does not block.
-            try {
-                wsConnection = WSConnection.connectHALSim(true);
-            } catch (URISyntaxException e) {
-                LOG.log(Level.ERROR,
-                        "Error occurred connecting to server:", e);
-                System.exit(1);
-                return;
-            }
-
             Runtime.getRuntime().addShutdownHook(new Thread(() -> {
                 // If connections haven't already been closed, we try to close them now. Note that
                 // this might silently fail if it takes too long.