[PATCH] kunit: tool: Do not colorize output when redirected

[Kees Cook]

Filling log files with color codes makes diffs and other comparisons
difficult. Only emit vt100 codes when the stdout is a TTY.

Cc: Brendan Higgins <brendan...@google.com>
Cc: linux-k...@vger.kernel.org
Cc: kuni...@googlegroups.com
Signed-off-by: Kees Cook <kees...@chromium.org>
---
tools/testing/kunit/kunit_parser.py | 7 +++++++
1 file changed, 7 insertions(+)

diff --git a/tools/testing/kunit/kunit_parser.py b/tools/testing/kunit/kunit_parser.py
index 05ff334761dd..807ed2bd6832 100644
--- a/tools/testing/kunit/kunit_parser.py
+++ b/tools/testing/kunit/kunit_parser.py
@@ -11,6 +11,7 @@

from __future__ import annotations
import re
+import sys

import datetime
from enum import Enum, auto
@@ -503,14 +504,20 @@ RESET = '\033[0;0m'

def red(text: str) -> str:
"""Returns inputted string with red color code."""
+ if not sys.stdout.isatty():
+ return text
return '\033[1;31m' + text + RESET

def yellow(text: str) -> str:
"""Returns inputted string with yellow color code."""
+ if not sys.stdout.isatty():
+ return text
return '\033[1;33m' + text + RESET

def green(text: str) -> str:
"""Returns inputted string with green color code."""
+ if not sys.stdout.isatty():
+ return text
return '\033[1;32m' + text + RESET

ANSI_LEN = len(red(''))
--
2.30.2

[David Gow]

On Thu, Feb 24, 2022 at 1:53 PM Kees Cook <kees...@chromium.org> wrote:
>
> Filling log files with color codes makes diffs and other comparisons
> difficult. Only emit vt100 codes when the stdout is a TTY.
>
> Cc: Brendan Higgins <brendan...@google.com>
> Cc: linux-k...@vger.kernel.org
> Cc: kuni...@googlegroups.com
> Signed-off-by: Kees Cook <kees...@chromium.org>
> ---

Ah, you can tell a tool has "made it" when people are redirecting its output!

This works fine here.

Reviewed-by: David Gow <davi...@google.com>

Thanks,
-- David

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[Kees Cook]

On Thu, Feb 24, 2022 at 02:43:53PM +0800, David Gow wrote:
> On Thu, Feb 24, 2022 at 1:53 PM Kees Cook <kees...@chromium.org> wrote:
> >
> > Filling log files with color codes makes diffs and other comparisons
> > difficult. Only emit vt100 codes when the stdout is a TTY.
> >
> > Cc: Brendan Higgins <brendan...@google.com>
> > Cc: linux-k...@vger.kernel.org
> > Cc: kuni...@googlegroups.com
> > Signed-off-by: Kees Cook <kees...@chromium.org>
> > ---
>
> Ah, you can tell a tool has "made it" when people are redirecting its output!

Heheh. Indeed! I have some more patches coming where I put a diff of
output in the commit log. ;)

> This works fine here.
>
> Reviewed-by: David Gow <davi...@google.com>

Thanks!

-Kees

--
Kees Cook

[Daniel Latypov]

I'd been thinking about doing this for a while.
I'd just gotten used to removing them via sed, or ending pipes with less -R.
I totally agree it's for the best that colors be turned off by default
when piping.

My hesitation was whether we'd want to introduce a flag like grep et al have.
I.e. --color=auto/always/etc.

Pros:
* consistency with grep, maybe less surprise
* allows wrappers around kunit.py to redirect output and still show color
* this is very niche and I know it. But I happen to own such a wrapper :)

Cons:
* an extra flag that's very niche
* I'm likely the only person to have ever used `kunit.py run | ... | less -R`
* the logic to check for coloring becomes more complicated, need to add a helper

I'm fine if we just stick with this simpler approach or do it later.
My aforementioned wrapper only redirects stdout when necessary anyways.

> return '\033[1;31m' + text + RESET
>
> def yellow(text: str) -> str:
> """Returns inputted string with yellow color code."""
> + if not sys.stdout.isatty():
> + return text
> return '\033[1;33m' + text + RESET
>
> def green(text: str) -> str:
> """Returns inputted string with green color code."""
> + if not sys.stdout.isatty():
> + return text
> return '\033[1;32m' + text + RESET
>
> ANSI_LEN = len(red(''))
> --
> 2.30.2
>

[Brendan Higgins]

On Thu, Feb 24, 2022 at 12:53 AM Kees Cook <kees...@chromium.org> wrote:
>
> Filling log files with color codes makes diffs and other comparisons
> difficult. Only emit vt100 codes when the stdout is a TTY.
>
> Cc: Brendan Higgins <brendan...@google.com>
> Cc: linux-k...@vger.kernel.org
> Cc: kuni...@googlegroups.com
> Signed-off-by: Kees Cook <kees...@chromium.org>

Reviewed-by: Brendan Higgins <brendan...@google.com>