Error in launching file

[ROxX]

I cannot find the error in these files. I tried ros2 run and get a error that says not executable file. I tried to put all the docs in order.

[roalgoal]

Hi @ROxX, based on your screenshots of your file names, you’ve added the console scripts incorrectly in setup.py.

How it should be:

'executable_name = pkg_name.file_name:main'

I can only see quiz_client.py and quiz_server.py in your package, so it makes sense that server_test and client_test would give you issues.

[ROxX]

Thank you for the response. Many of the examples use similar names for files, executable, and pkg. I changed the setup file but now have a different error. I thought the executable was the same as the super__init__ node. I am still not understanding some critical basic requirements.

[roalgoal]

This can be two things:

1. Your launch file services_quiz_server.launch.py is still incorrectly calling for an executable server_test. If that’s the case, you need to change to the name specified in setup.py, recompile, source, and launch again.
2. The compilation directories (/build , /install) still have information related to server_test which is giving out errors. Based on your error output, this is less likely. But to fix this, you can just remove the directories and compile, source, and launch again: cd ~/ros2_ws && rm -rf /build /install && colcon build && source install/setup.bash

As for your confusion with super().__init__('client_test'), it’s important to differentiate what each thing is and what it does:

• An executable is a program that can be run by an operating system. These are written in many languages, not just Python. In order for ROS 2 to find and run the program you write, it has to be structured in a specific way and it has to provide instructions for the operating system on where to find it. This structure is a package inside a workspace, and the package contains the instructions. You define these in setup.py (and in C++, in CMakeLists.txt)
• super().__init__('client_test') is a built in method in Python that invokes a constructor of the parent class it is in (in this case, Node from rclpy.node). This is all Python, and has nothing to do with ROS 2 or its structure

[ROxX]

Thank you for your response, I renamed the executable in both launch and setup.py files and the error is still there. I ran the remove and install code as well. Here are all the files.

[roalgoal]

The first part of those console scripts in setup.py are actually the executable names. You need to change them since what you are doing:

ros2 run [PACKAGE_NAME] [EXECUTABLE_NAME]
ros2 run services_quiz quiz_client

is calling for quiz_client, but the executable names you have are client_test_2 and server_test_2. Change those to:

entry_ponts={
  'console_scripts' : [
    '[EXECUTABLE_NAME] = [PACKAGE_NAME][FILE_NAME]:main'
    'quiz_client = ...

[ROxX]

Thank you for your review. I found an error in the setup.py file. I missed a comma in the console scripts file between the two lines that define the executable. I now have successfully completed the quiz and will submit it for review and grading. I really appreciate the reviews that you and others provide.