Heartbeat

rb_ws/src/buggy/buggy/watchdog/watchdog_node.py

@@ -0,0 +1,59 @@
+import rclpy
+from rclpy.node import Node
+
+from std_msgs.msg import Bool
+
+class Watchdog(Node):
+
+    def __init__(self):
+        """
+        Constructor for Watchdog class.
+
+        Creates a ROS node with a publisher that periodically sends a message
+        indicating whether the node is still alive.
+
+        """
+        super().__init__('watchdog')
+
+        # Publishers
+        self.heartbeat_publisher = self.create_publisher(Bool, 'self/debug/heartbeat', 1)
+
+        # Subscribers
+        self.heartbeat_subscriber = self.create_subscription(Bool, 'self/debug/heartbeat', self.heartbeat_listener, 1)
+
+        timer_period = 0.01  # seconds (100 Hz)
+        self.timer = self.create_timer(timer_period, self.loop)
+        self.i = 0 # Loop Counter
+
+    def loop(self):
+        # Loop for the code that operates every 10ms
+        msg = Bool()
+        msg.data = True
+        self.heartbeat_publisher.publish(msg)
+
+    def heartbeat_listener(self, msg : Node):
+        """
+        Subscriber Function that checks if Heartbeat is ever alse
+        It never actually is false, this is just a demonstration of a subscriber
+        If it ever actually is false, something cursed has happened
+        """
+        if msg.data == False:
+            self.get_logger().error("Hearbeat Failed!")
+
+
+def main(args=None):
+    rclpy.init(args=args)
+
+    watchdog = Watchdog()
+
+    rclpy.spin(watchdog)
+
+    # Destroy the node explicitly
+    # (optional - otherwise it will be done automatically
+    # when the garbage collector destroys the node object)
+    watchdog.destroy_node()
+    rclpy.shutdown()
+
+
+if __name__ == '__main__':
+    main()

rb_ws/src/buggy/launch/watchdog.xml

@@ -0,0 +1,4 @@
+<launch>
+    <node pkg="foxglove_bridge" exec="foxglove_bridge" name="foxglove" namespace="SC"/>
+    <node pkg="buggy" exec="watchdog" name="SC_watchdog" namespace="SC"/>
+</launch>

rb_ws/src/buggy/setup.py

@@ -13,7 +13,7 @@
         ('share/ament_index/resource_index/packages',
             ['resource/' + package_name]),
         ('share/' + package_name, ['package.xml']),
-        (os.path.join("share", package_name), glob("launch/*.xml")),
+        (os.path.join("share", package_name), glob("launch/*.xml"))
     ],
     install_requires=['setuptools'],
     zip_safe=True,
@@ -24,7 +24,8 @@
     tests_require=['pytest'],
     entry_points={
         'console_scripts': [
-            'hello_world = buggy.hello_world:main'
+            'hello_world = buggy.hello_world:main',
+            'watchdog = buggy.watchdog.watchdog_node:main'
         ],
     },
-)
+)