ros2中创建一个python package

完整的python package的目录结构如下:

source /opt/ros/dashing/setup.bash
cd ros2_ws/src && ros2 pkg create <package_name>
Delete CMakeLists.txt , create setup.py and setup.cfg and edit package.xml

setup.py内容参考:

from setuptools import setup

package_name = 'ros2_demo_py'

setup(

    name=package_name,

    version='0.7.0',

    packages=[package_name],

    install_requires=['setuptools'],

    zip_safe=True,

    author='You',

    author_email='you@youremail.com',

    maintainer='YourFirstname Lastname',

    maintainer_email='your@youremail.com',

    keywords=['ROS'],

    classifiers=[

        'Intended Audience :: Developers',

        'License :: OSI Approved :: Apache Software License',

        'Programming Language :: Python',

        'Topic :: Software Development',

    ],

    description='A simple ROS2 Python package',

    license='Apache License, Version 2.0',

    tests_require=['pytest'],

    entry_points={

        'console_scripts': [

            'demo = ros2_demo_py.demo:main'

        ],

    },

)

fbi warning!!!!!!!!!

'console_scripts': [

'demo = ros2_demo_py.demo:main'

告知ros2如何加载脚本.比如ros2 run ros2_demo_py demo实际上就是说要去执行ros2_demo_py/demo.py的main()函数. 更改setup.py后必须重新colcon build才会生效.

当我改成'console_scripts': [

'fuck_ = ros2_demo_py.what:main'

],时,相应的执行命令就变为ros2 run ros2_demo_py fuck_,执行的就是ros2_demo_py/what.py的main()函数

setup.cfg内容参考:

[develop]

script-dir=$base/lib/ros2_demo_py

[install]

install-scripts=$base/lib/ros2_demo_py

package.xml内容参考:

<?xml version="1.0"?>

<?xml-model href="http://download.ros.org/schema/package_format2.xsd" schematypens="http://www.w3.org/2001/XMLSchema"?>

<package format="2">

  <name>ros2_demo_py</name>

  <version>0.7.3</version>

  <description>A simple ROS2 Python package</description>

  <maintainer email="sloretz@openrobotics.org">Shane Loretz</maintainer>

  <license>Apache License 2.0</license>

  <exec_depend>rclpy</exec_depend>

  <exec_depend>std_msgs</exec_depend>

  <!-- These test dependencies are optional

  Their purpose is to make sure that the code passes the linters -->

  <test_depend>ament_copyright</test_depend>

  <test_depend>ament_flake8</test_depend>

  <test_depend>ament_pep257</test_depend>

  <test_depend>python3-pytest</test_depend>

  <export>

    <build_type>ament_python</build_type>

  </export>

</package>

创建python代码

demo.py

# Copyright 2016 Open Source Robotics Foundation, Inc.

#

# Licensed under the Apache License, Version 2.0 (the "License");

# you may not use this file except in compliance with the License.

# You may obtain a copy of the License at

#

#     http://www.apache.org/licenses/LICENSE-2.0

#

# Unless required by applicable law or agreed to in writing, software

# distributed under the License is distributed on an "AS IS" BASIS,

# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

# See the License for the specific language governing permissions and

# limitations under the License.

import rclpy

from rclpy.node import Node

from std_msgs.msg import String

class MinimalPublisher(Node):

    def __init__(self):

        super().__init__('minimal_publisher')

        self.publisher_ = self.create_publisher(String, 'topic')

        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.data = 'Hello World: %d' % 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()