I am using ROS-noetic and ROS2-foxy in the same machine. I created a package in ros2, and write this obstacle_maneuver.py file,

import rclpy from rclpy.node import Node from sensor_msgs.msg import LaserScan from geometry_msgs.msg import Twist class ObstacleAvoidingBot(Node): def __init__(self): super().__init__('Go_to_position_node') ## name of the node self.publisher = self.create_publisher(Twist, '/cmd_vel', 40) self.subscription=self.create_subscription(LaserScan,'/scan',self.get_scan_values,40) #periodic call timer_period = 0.2;self.timer = self.create_timer(timer_period, self.send_cmd_vel) ## Initializing Global values for linear velocity self.linear_vel = 0.22 ## dividing the area of laser scan (720/120) self.regions={'front_right':0.0,'front':0.0,'front_left':0.0, 'rear_left':0.0, 'back':0.0, 'rear_right':0.0} ## creating a message object to fit new velocities and publish them self.velocity=Twist() ## Subscriber Callback function def get_scan_values(self,scan_data): ## We have 360 data points and we are dividing them in 3 regions ## we say if there is something in the region get the smallest value self.regions = { 'front_right': min(scan_data.ranges[0:60]), 'front': min(scan_data.ranges[60:120]), 'front_left': min(scan_data.ranges[120:180]), 'rear_left': min(scan_data.ranges[180:240]), 'back': min(scan_data.ranges[240:300]), 'rear_right': min(scan_data.ranges[300:360]) } print(self.regions['front_right']," / ",self.regions['front']," / ",self.regions['front_left'], " / ",self.regions['rear_left'], " / ",self.regions['back'], " / ",self.regions['rear_right']) ## Callback Publisher of velocities called every 0.2 seconds def send_cmd_vel(self): ## angular and linear velocities are set into object self.velcity ## setting the linear velocity to be fixed and robot will keep on moving self.velocity.linear.x=self.linear_vel ## cases to make the robot change its angular velocity front_right_value = self.regions['front_right'] front_value = self.regions['front'] front_left_value = self.regions['front_left'] rear_left_value = self.regions['rear_left'] back_value = self.regions['back'] rear_right_value = self.regions['rear_right'] if all(value > 2 for value in [front_left_value, front_value, front_right_value, rear_right_value, back_value, rear_left_value]): self.velocity.angular.z = 0.0 # Area is total clear, move forward print("Forward") elif all(value > 2 for value in [front_value, front_right_value, rear_left_value, back_value, rear_right_value]) and front_left_value < 2: self.velocity.angular.z = 1.57 print("object in front_left, Moving front_right") elif all(value > 2 for value in [front_left_value, front_value, rear_right_value, rear_left_value, back_value]) and front_right_value < 2: self.velocity.angular.z = -1.57 print("object in front_right,Moving front_left") elif all(value > 2 for value in [front_value, rear_right_value, rear_left_value, back_value]) and front_right_value < 2 and front_left_value < 2: self.velocity.angular.z = 0.0 print("object in front_right and front_left ,Moving forward") elif all(value > 2 for value in [rear_right_value, rear_left_value, back_value]) and front_right_value < 2 and front_left_value < 2 and front_value < 2: self.velocity.angular.z = 3.14 print("object in front_right, front_left and front, going reverse") elif all(value > 2 for value in [rear_right_value]) and rear_left_value < 2 and front_left_value < 2 and front_value < 2 and front_right_value < 2 and back_value < 2: self.velocity.angular.z = 1.57 print("object in front_left, front, front_right, rear_left and back, Moving rear_right") elif all(value > 2 for value in [rear_left_value]) and rear_right_value < 2 and front_left_value < 2 and front_value < 2 and front_right_value < 2 and back_value < 2: self.velocity.angular.z = -1.57 print("object in front_left, front, front_right, rear_right and back, Moving rear_left") elif all(value > 2 for value in [back_value]) and rear_right_value < 2 and front_left_value < 2 and front_value < 2 and front_right_value < 2 and rear_left_value < 2: self.velocity.angular.z = 3.14 print("object in front_left, front, front_right, rear_right and rear_left_value, going reverse") elif all(value > 2 for value in [front_value]) and rear_right_value < 2 and front_left_value < 2 and back_value < 2 and front_right_value < 2 and rear_left_value < 2: self.velocity.angular.z = 0.0 print("object in front_left, back, front_right, rear_right and rear_left_value, going straight") else: #self.velocity.angular.z = 0.0 # Stop if none of the above conditions are met print("Robot stopped") ## lets publish the complete velocity self.publisher.publish(self.velocity) def main(args=None): rclpy.init(args=args) oab=ObstacleAvoidingBot() rclpy.spin(oab) rclpy.shutdown() if __name__ == '__main__': main() 

this is the setup.py file

from setuptools import setup import os from glob import glob package_name = 'my_rover' setup( name=package_name, version='0.0.0', packages=[package_name], data_files=[ ('share/ament_index/resource_index/packages', ['resource/' + package_name]), ('share/' + package_name, ['package.xml']), (os.path.join('share', package_name), glob('launch/*.py')), (os.path.join('share', package_name), glob('urdf/*')), ], install_requires=['setuptools'], zip_safe=True, maintainer='vasanth', maintainer_email='[email protected]', description='TODO: Package description', license='TODO: License declaration', tests_require=['pytest'], entry_points={ 'console_scripts': [ 'obstacle_avoidance = my_rover.obstacle_maneuver:main' ], }, ) 

when i run this command ros2 run my_rover obstacle_avoidance, after i gave source /opt/ros/foxy/src and source ~/colcon_ws/install/setup.bash, this is the error my terminal shows...

Traceback (most recent call last): File "/home/vasanth/colcon_ws/install/my_rover/lib/my_rover/obstacle_avoidance", line 11, in <module> load_entry_point('my-rover==0.0.0', 'console_scripts', 'obstacle_avoidance')() File "/home/vasanth/colcon_ws/install/my_rover/lib/python3.8/site-packages/my_rover/obstacle_maneuver.py", line 117, in main oab=ObstacleAvoidingBot() File "/home/vasanth/colcon_ws/install/my_rover/lib/python3.8/site-packages/my_rover/obstacle_maneuver.py", line 11, in __init__ self.publisher = self.create_publisher(Twist, '/cmd_vel', 40) File "/opt/ros/foxy/lib/python3.8/site-packages/rclpy/node.py", line 1144, in create_publisher check_for_type_support(msg_type) File "/opt/ros/foxy/lib/python3.8/site-packages/rclpy/type_support.py", line 20, in check_for_type_support ts = msg_type.__class__._TYPE_SUPPORT AttributeError: type object 'type' has no attribute '_TYPE_SUPPORT' This might be a ROS 1 message type but it should be a ROS 2 message type. Make sure to source your ROS 2 workspace after your ROS 1 workspace. 

and this shows in the terminal when i run source ~/colcon_ws/install/setup.bash

source ~/colcon_ws/install/setup.bash ROS_DISTRO was set to 'foxy' before. Please make sure that the environment does not mix paths from different distributions. ROS_DISTRO was set to 'noetic' before. Please make sure that the environment does not mix paths from different distributions. 

why it's shows both two workspaces at the same time?