Re: [PATCH 2/2] tests: Evict stale files in the functional download cache after a while

["Daniel P. Berrangé" <berrange@redhat.com>]

On Mon, Oct 13, 2025 at 01:47:57PM +0200, Thomas Huth wrote:
> On 10/10/2025 11.50, Daniel P. Berrangé wrote:
> > On Fri, Oct 10, 2025 at 11:32:43AM +0200, Thomas Huth wrote:
> > > From: Thomas Huth <thuth@redhat.com>
> > > 
> > > The download cache of the functional tests is currently only growing.
> > > But sometimes tests get removed or changed to use different assets,
> > > thus we should clean up the stale old assets after a while when they
> > > are not in use anymore. So add a script that looks at the time stamps
> > > of the assets and removes them if they haven't been touched for more
> > > than half of a year. Since there might also be some assets around that
> > > have been added to the cache before we added the time stamp files,
> > > assume a default time stamp that is close to the creation date of this
> > > patch, so that we don't delete these files too early.
> > > 
> > > Signed-off-by: Thomas Huth <thuth@redhat.com>
> > > ---
> > >   MAINTAINERS                       |  1 +
> > >   scripts/clean_functional_cache.py | 47 +++++++++++++++++++++++++++++++
> > >   tests/Makefile.include            |  1 +
> > >   3 files changed, 49 insertions(+)
> > >   create mode 100755 scripts/clean_functional_cache.py
> > > 
> > > diff --git a/MAINTAINERS b/MAINTAINERS
> > > index 84cfd85e1fa..4c468d45337 100644
> > > --- a/MAINTAINERS
> > > +++ b/MAINTAINERS
> > > @@ -4398,6 +4398,7 @@ M: Thomas Huth <thuth@redhat.com>
> > >   R: Philippe Mathieu-Daudé <philmd@linaro.org>
> > >   R: Daniel P. Berrange <berrange@redhat.com>
> > >   F: docs/devel/testing/functional.rst
> > > +F: scripts/clean_functional_cache.py
> > >   F: tests/functional/qemu_test/
> > >   Windows Hosted Continuous Integration
> > > diff --git a/scripts/clean_functional_cache.py b/scripts/clean_functional_cache.py
> > > new file mode 100755
> > > index 00000000000..e5c4d1acaf3
> > > --- /dev/null
> > > +++ b/scripts/clean_functional_cache.py
> > > @@ -0,0 +1,47 @@
> > > +#!/usr/bin/env python3
> > > +#
> > > +# SPDX-License-Identifier: GPL-2.0-or-later
> > > +#
> > > +"""Delete stale assets from the download cache of the functional tests"""
> > > +
> > > +import os
> > > +import stat
> > > +import sys
> > > +import time
> > > +from pathlib import Path
> > > +
> > > +
> > > +cache_dir_env = os.getenv('QEMU_TEST_CACHE_DIR')
> > > +if cache_dir_env:
> > > +    cache_dir = Path(cache_dir_env, "download")
> > > +else:
> > > +    cache_dir = Path(Path("~").expanduser(), ".cache", "qemu", "download")
> > 
> > This creates a Path object but then doesn't take advantage of
> > any of its functionality, calling os. functions still....
> 
> Ok, you got me, looks like I'm still a python ignorant after one year of
> hacking the functional testing framework ;-) Thanks for the hints how to do
> it better!
> 
> > > +    try:
> > > +        with open(filename + ".stamp", "r", encoding='utf-8') as fh:
> > > +            timestamp = int(fh.read())
> > 
> >     timestamp = file.read_text()
> 
> Hmm, but "file" points to the asset, not to the .stamp file, doesn't it?

Opps, yes, you'll need

  file.with_stem(".stamp").read_text()

> > > +    except FileNotFoundError:
> > > +        # Assume it's an old file that was already in the cache before we
> > > +        # added the code for evicting stale assets. Use the release date
> > > +        # of QEMU v10.1 as a default timestamp.
> > > +        timestamp = time.mktime((2025, 8, 26, 0, 0, 0, 0, 0, 0))
> > 
> > The prev patch will make the precache task create the .stamp for all
> > files that are currently in use by the current branch. So the only
> > thing this does is to prevent us deleting cached files that might
> > still be needed by a different branch. There will be few of them,
> > so if we prematurely delete a handful that's not a big deal. If we
> > switch to checking mtime, this except won't even exist.
> 
> When hunting regressions that have been introduced recently, I often have to
> do bisecting on revisions from the previous 1 or 2 QEMU releases, so I'd
> prefer keeping the assets of the last few months, even if they have been
> removed from the master branch in a very recent commit.

Ok.

With regards,
Daniel
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