Python `invoke` not printing with multiline commands on Windows

Question

When using the invoke library from Windows, it seems like no output is printed to the terminal if the command spans multiple lines. Here's an example to reproduce; put this in tasks.py.

import invoke

@invoke.task
def test_oneline(ctx):
    ctx.run("pip install nonexistant-package1234")

@invoke.task
def test_multiline(ctx):
    ctx.run(
    """
    pip install nonexistant-package1234
    """
    )

Then, from the command prompt in the same directory as tasks.py, I get the following:

>invoke test-oneline
Collecting nonexistant-package1234
  Could not find a version that satisfies the requirement nonexistant-package1234 (from versions: )
No matching distribution found for nonexistant-package1234
>

>invoke test-multiline

>

Doing the same thing on Linux (well, at least Windows Subsystem for Linux) works as expected:

$ invoke test-multiline
Collecting nonexistant-package1234
  Could not find a version that satisfies the requirement nonexistant-package1234 (from versions: )
No matching distribution found for nonexistant-package1234
$

Is there a way to get the output printed in Windows for multi-line commands?

Nathan · Answer 1 · 2019-02-21T19:58:59.923

Here's the hack that I'm using for now in case others need to circumvent this in the short run. I'll post back if I encounter issues with it; it's only minimally tested so far. Basically, if you're on Windows, I just write the command into a .bat file, then I run the .bat file (as a single-line command).

import invoke
import platform
from pathlib import Path
from tempfile import TemporaryDirectory


def _fixed_run(ctx, cmd: str, *args, **kwargs):
    if platform.system() != "Windows":
        return ctx._old_run(cmd, *args, **kwargs)

    with TemporaryDirectory() as tmp_dir:
        tmp_file = Path(tmp_dir) / "tmp.bat"
        tmp_file.write_text("@echo off\r\n" + cmd)
        return ctx._old_run(str(tmp_file), *args, **kwargs)

invoke.Context._old_run = invoke.Context.run
invoke.Context.run = _fixed_run

To use this easily, save it into a file (e.g. fix_invoke.py and then just do import fix_invoke whenever you need this fix).

I'd be glad to hear of a real solution, though, if anybody has one!

Python `invoke` not printing with multiline commands on Windows

1 Answers1