[PATCH 2/2] add test for CACHEDIR.TAG creation in build dir

[Felix Moessbauer]

Signed-off-by: Felix Moessbauer <felix.mo...@siemens.com>
---
tests/test_commands.py | 14 ++++++++++++++
1 file changed, 14 insertions(+)

diff --git a/tests/test_commands.py b/tests/test_commands.py
index d0f7344ac..e891bf841 100644
--- a/tests/test_commands.py
+++ b/tests/test_commands.py
@@ -518,3 +518,17 @@ def test_cmd_not_found(monkeykas, tmpdir):
assert ret != 0
with pytest.raises(FileNotFoundError):
run_cmd(cmd, tmpdir, os.environ, fail=True)
+
+
+...@pytest.mark.dirsfromenv
+def test_build_dir_add_cachedir_tag(monkeykas, tmpdir):
+ tdir = str(tmpdir.mkdir('test_build_dir_add_cachedir_tag'))
+ shutil.rmtree(tdir, ignore_errors=True)
+ shutil.copytree('tests/test_commands', tdir)
+ monkeykas.chdir(tdir)
+
+ kas.kas(['checkout', 'test-local.yml'])
+ cachetag = monkeykas.get_kbd() / 'CACHEDIR.TAG'
+ assert cachetag.exists()
+ with cachetag.open() as f:
+ assert f.readline().startswith('Signature:')
--
2.51.0

[Felix Moessbauer]

The kas build directory contains temporary data and the build artifacts.
These qualify for a CACHEDIR.TAG, which helps to exclude these
directories from backups.

Signed-off-by: Felix Moessbauer <felix.mo...@siemens.com>
---

docs/command-line/environment-variables.inc | 1 +
kas/libcmds.py | 4 +++-
kas/libkas.py | 18 ++++++++++++++++++
3 files changed, 22 insertions(+), 1 deletion(-)

diff --git a/docs/command-line/environment-variables.inc b/docs/command-line/environment-variables.inc
index 9cc6884a5..62d366d60 100644
--- a/docs/command-line/environment-variables.inc
+++ b/docs/command-line/environment-variables.inc
@@ -58,6 +58,7 @@ overwritten using the ``env`` section of the config file.
| ``KAS_BUILD_DIR`` | The path of the build directory, |
| (C, K) | ``${KAS_WORK_DIR}/build`` is the default. |
| | The parent directory must exist if set. |
+| | kas adds a ``CACHEDIR.TAG``. |
+--------------------------+--------------------------------------------------+
| ``KAS_REPO_REF_DIR`` | The path to the repository reference directory. |
| (C, K) | Repositories in this directory are used as |
diff --git a/kas/libcmds.py b/kas/libcmds.py
index 05f0871ba..3a651bfb6 100644
--- a/kas/libcmds.py
+++ b/kas/libcmds.py
@@ -34,7 +34,8 @@ import base64
from pathlib import Path
from git.config import GitConfigParser
from .libkas import (ssh_cleanup_agent, ssh_setup_agent, ssh_no_host_key_check,
- get_build_environ, repos_fetch, repos_apply_patches)
+ get_build_environ, repos_fetch, repos_apply_patches,
+ add_cachedir_tag)
from .context import ManagedEnvironment as ME
from .context import get_context
from .includehandler import IncludeException
@@ -429,6 +430,7 @@ class SetupDir(Command):
def execute(self, ctx):
if not os.path.exists(ctx.build_dir):
os.mkdir(ctx.build_dir)
+ add_cachedir_tag(ctx.build_dir, "kas build directory")


class SetupSSHAgent(Command):
diff --git a/kas/libkas.py b/kas/libkas.py
index 801134f42..327803476 100644
--- a/kas/libkas.py
+++ b/kas/libkas.py
@@ -626,6 +626,24 @@ def ssh_no_host_key_check():
ssh_config)


+def add_cachedir_tag(dir, comment=None):
+ """
+ Create a CACHEDIR.TAG below dir. If a comment is provided,
+ as this to the tag as well.
+ """
+ cachetag = pathlib.Path(dir) / 'CACHEDIR.TAG'
+ if cachetag.exists():
+ return
+ with open(cachetag, 'w') as f:
+ logging.debug('create CACHEDIR.TAG in %s', str(dir))
+ f.write('Signature: 8a477f597d28d172789f06886806bc55\n')
+ f.write('# This file is a cache directory tag created by kas.\n'
+ '# For information about cache directory tags, see:\n'
+ '# https://bford.info/cachedir/spec.html\n')
+ if comment:
+ f.write(f'#\n# {comment}\n')
+
+
def setup_parser_common_args(parser):
from kas.libcmds import Macro

--
2.51.0

[Jan Kiszka]

Thanks, both applied.

Jan

--
Siemens AG, Foundational Technologies
Linux Expert Center

[Florian Bezdeka]

On Fri, 2026-02-27 at 12:24 +0100, 'Felix Moessbauer' via kas-devel
wrote:

> The kas build directory contains temporary data and the build artifacts.
> These qualify for a CACHEDIR.TAG, which helps to exclude these
> directories from backups.
>

Just minor drive-by comments, see below

s/as/add

> + """
> + cachetag = pathlib.Path(dir) / 'CACHEDIR.TAG'

os.path.join() ?

> + if cachetag.exists():
> + return
> + with open(cachetag, 'w') as f:
> + logging.debug('create CACHEDIR.TAG in %s', str(dir))

Why no format (f-) string as below?

> + f.write('Signature: 8a477f597d28d172789f06886806bc55\n')
> + f.write('# This file is a cache directory tag created by kas.\n'
> + '# For information about cache directory tags, see:\n'
> + '# https://bford.info/cachedir/spec.html\n')
> + if comment:
> + f.write(f'#\n# {comment}\n')
> +
> +
> def setup_parser_common_args(parser):
> from kas.libcmds import Macro
>
> --
> 2.51.0
>

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[Jan Kiszka]

Fixing up.

>> + """
>> + cachetag = pathlib.Path(dir) / 'CACHEDIR.TAG'
>
> os.path.join() ?
>

"/" is the join operator.

>> + if cachetag.exists():
>> + return
>> + with open(cachetag, 'w') as f:
>> + logging.debug('create CACHEDIR.TAG in %s', str(dir))
>
> Why no format (f-) string as below?
>

Valid cleanup, done in next now.

[MOESSBAUER, Felix]

Exactly. In general, I would like to use pathlib.Path in new code, as
this is typed (useful once we introduce type hints) while os.path is
string based, hence inherits all kinds of path escaping issues.

>
> > > + if cachetag.exists():
> > > + return
> > > + with open(cachetag, 'w') as f:
> > > + logging.debug('create CACHEDIR.TAG in %s', str(dir))
> >
> > Why no format (f-) string as below?

Also possible, but I dislike calling functions in the f- strings.
It's a matter of taste, though.

> >
>
> Valid cleanup, done in next now.

Thanks!

Felix

>
> Jan
>
> --
> Siemens AG, Foundational Technologies
> Linux Expert Center

--
Siemens AG
Linux Expert Center
Friedrich-Ludwig-Bauer-Str. 3
85748 Garching, Germany