How to setup Visual Studio Code stdin/stdout redirection for Python (debugger)?

Question

I am using Visual Studio Code to debug my Python code.

I want to redirect one text file in stdin and the output be written in another file.

I can reach that by running python directly using the following syntax:

python code.py < input.txt > output.txt

Is there a way to allow that while debugging the script? If that is not possible, can I create a configuration for running python with that parameters. I tried using args parameter in the launch.json, but those are all placed into quotes that defeats the purpose of this redirection.

Answer 1

I was able to achieve this using the args parameter in the launch.json config file:

{
    // Use IntelliSense to learn about possible attributes.
    // Hover to view descriptions of existing attributes.
    // For more information, visit: https://go.microsoft.com/fwlink/?linkid=830387

    "version": "0.2.0",
    "configurations": [
        {
            "name": "Python: Aktuelle Datei",
            "type": "python",
            "request": "launch",
            "program": "${file}",
            "console": "integratedTerminal",
            "args": [ "<", "input.txt",
                 ">", "output.txt" ]
        }
    ]
}

When running the debugger you get the following command line:

bash-3.2$  env DEBUGPY_LAUNCHER_PORT=51669 /usr/local/opt/python/bin/python3.7 /Users/XXXX/.vscode/extensions/ms-python.python-2020.4.76186/pythonFiles/lib/python/debugpy/wheels/debugpy/launcher "/Users/XXXX/my_script.py" < input.txt > output.txt 

Visual Studio Code 1.45
macOS 10.14.6

Answer 2

There isn't any built-in solution, but if you modified your app to replace sys.stdin and sys.stdout with what you would like to be considered stdin and stdout you could get the same effect.