ROS2 Flask Threading issue

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Hi all,

I am trying to set up a ROS2 rclpy node that functions as a Flask socket server. This node needs to have a thread or timer-based process running (which handles a socket broadcast). The issue I am running into is that when I create a ROS2 timer, it seems that it never executes, and when I use a python thread, it seems to block the main process. The minimal code samples are below:

ROS2 Timer:

class MyNode(Node):

    def __init__(self):
        super(MyNode,self).__init__('my_node')
        self.get_logger().info('Initializing My Node!') # Works fine
        self.app = Flask(__name__) # Flask Stuff
        self.my_ns = NS(self)     # Custom Flask Socket Namespace
        self.socketio = SocketIO(self.app, cors_allowed_origins="*") # Create Socket
        self.socketio.on_namespace(self.my_ns) # Pair the namespace
        self.process_timer = self.create_timer(.1,self.process)
        self.get_logger().info('Initialized!') # Executes

    def process(self):
        self.get_logger().info('Running!') # Never Executes

def main(args=None):
    rclpy.init(args=args)
    node = MyNode()
    node.socketio.run(node.app)

if __name__ == '__main__':
    main()

Python Thread:

class MyNode(Node):

    def __init__(self):
        super(MyNode,self).__init__('my_node')
        self.get_logger().info('Initializing My Node!') # Works fine
        self.app = Flask(__name__) # Flask Stuff
        self.my_ns = NS(self)     # Custom Flask Socket Namespace
        self.socketio = SocketIO(self.app, cors_allowed_origins="*") # Create Socket
        self.socketio.on_namespace(self.my_ns) # Pair the namespace
        self.process_thread = Thread(target=self.process,daemon=True)
        self.process_thread.start()
        self.get_logger().info('Initialized!') # Never Executes

    def process(self):
        alive = True
        while alive:
           try:
              self.assert_liveliness()
              self.get_logger().info('Running!') # Executes
            except:
              alive = False


def main(args=None):
    rclpy.init(args=args)
    node = MyNode()
    node.socketio.run(node.app)

if __name__ == '__main__':
    main()

Thanks for the suggestions, and I will try out those changes. I should share the original code I had, which is the following:

class WizardNode(Node):

    def __init__(self):
        super(WizardNode,self).__init__('wizard')
        self.get_logger().info('Initializing Wizard Node!')
        self.app = Flask(__name__)
        self.cors = CORS(self.app)
        self.wizard = Wizard(self)
        self.socketio = SocketIO(self.app, cors_allowed_origins="*")
        self.socketio.on_namespace(self.wizard)
        self.socket_thread = Thread(target=lambda:self.socketio.run(self.app),daemon=True)
        self.socket_thread.start()
        self.process_timer = self.create_timer(.1,self.process)
        self.get_logger().info('Initialized!')
        self.printer = PrettyPrinter()

    def process(self):
        time = self.get_clock().now()
        self.wizard.timestep()



def main(args=None):
    rclpy.init(args=args)

    node = WizardNode()
    try:
        rclpy.spin(node)
    except KeyboardInterrupt:
        pass

    node.destroy_node()
    rclpy.shutdown() 

In this version, it seems that the socket.io thread fails to do any sort of broadcasting/emitting, which was why I tried restructuring in the ways above. I should also say that in this example, using eventlet's monkey_patch() basically broke everything.