ROS2 custom message python import error

Hi Deatails: ROS Env

ROS_VERSION=2
ROS_PYTHON_VERSION=3
ROS_LOCALHOST_ONLY=0
ROS_DISTRO=foxy

I created a custom message as follows in Custom.msg file

uint32 number

I have a publisher code with as follows

import rclpy
from rclpy.node import Node

from std_msgs.msg import String

from ros_nodes import Custom


class MinimalPublisher(Node):

    def __init__(self):
        super().__init__('minimal_publisher')
        self.publisher_ = self.create_publisher(String, 'topic', 10)
        timer_period = 0.5  # seconds
        self.timer = self.create_timer(timer_period, self.timer_callback)
        self.i = 0

    def timer_callback(self):
        #msg = String()
        msg = Custom()
        msg.number = self.i
        self.publisher_.publish(msg)
        self.get_logger().info('Publishing: "%s"' % msg.data)
        self.i += 1


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

    minimal_publisher = MinimalPublisher()

    rclpy.spin(minimal_publisher)

    # Destroy the node explicitly
    # (optional - otherwise it will be done automatically
    # when the garbage collector destroys the node object)
    minimal_publisher.destroy_node()
    rclpy.shutdown()


if __name__ == '__main__':
    main()

When i try to run i am getting following error

ImportError: cannot import name 'Custom' from 'ros_nodes'

This error is not python import error but specific to that python is not able to import custo.msg Am i doing something wrong. Can you guys share a sample project. As of now i am not using CMakeList or package.xml I don't think any of them are required. How do we use ros generate message to get the message imported. What is the right way to do with custom messages in python.

Originally posted by Malz on ROS Answers with karma: 11 on 2020-06-20

Post score: 0