How to run a script before running/debugging a python script by vscode?

Question

I am working with ROS. ROS needs to source a few scripts e.g., /opt/ros/noetic/setup.sh before running any python programs. Otherwise I cannot import roslib or similar stuffs.

When I debug with vscode, is there any way to let vscode to source this script automatically before starting the debugger?

Dressingdown

Does this answer your question? How to set environment variables in vscode for debugging? – Clotho

It seems to be the same answer but using powershell instead of a Linux / MacOS terminal, which at least on Mac doesn't work and the debugger command isn't run after the script is run. – Jameljamerson

Answer 1

If your launch script allows you to specify a python target (and finishes quickly enough), you can use pythonArgs in launch.json to insert a shim.

.vscode/launch.json

{
    "version": "0.2.0",
    "configurations": [
        {
            "name": "Launch via Shell Script",
            "type": "python",
            "pythonArgs": ["debug_shim.py", "launch.sh"],
            "args": ["your", "app", "args"],
            "request": "launch",
            "program": "app.py"
        }
    ]
}

debug_shim.py

import os, subprocess, sys

launcher, debugger, debugger_args = sys.argv[1], sys.argv[2], sys.argv[3:]

sys.exit(subprocess.run(
    args=[launcher] + debugger_args,
    env=dict(os.environ, LAUNCH_TARGET=debugger),
    stdin=sys.stdin,
    stdout=sys.stdout,
    stderr=sys.stderr,
).returncode)

launch.sh

#!/usr/bin/env bash

# Or target could be passed along the command line as well.
# LAUNCH_TARGET="${1?}"

# ...stuff...

python "${LAUNCH_TARGET-app.py}" "${@}"

In my setup of v1.80.0 on WSL2, the debugger call is like so:

python python_args... debugger debugger_args... app app_args...

Then the call stack will be vscode -> shim -> launcher -> debugger -> app and the debugger will connect seamlessly, although if it takes more than several seconds VSCode will time out.

Combustion

Answer 2

Adding the setup scripts to your .bashrc file will ensure that they are sourced before vscode begins debugging your program. The ROS2 documentation supports this method and provides an example.

In your .bashrc file add the following:

source /opt/ros/${ROS_DISTRO}/setup.bash
source ~/ros2_ws/install/local_setup.bash

Barbey

Answer 3

You can have a try on Task, For example:

tasks.json file:

{
    "version": "2.0.0",
    "tasks": [
        {
            "label": "Task Name",
            "type": "shell",
            "command":"the commands you want to execute",
        }
    ]
}

And add this in the launch.json file:

"preLaunchTask": "Task Name",

You can refer to the official docs for more details.

Polygraph

Tasks run in a separate shell, and does not allow you to affect the debug environment/to source a script in a way that affects the debug-environment. – Portfire