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From: "Ludovic Courtès" <ludo@gnu.org>
To: Ricardo Wurmus <rekado@elephly.net>
Cc: guix-devel@gnu.org
Subject: Re: Caching calls to download-to-store?
Date: Thu, 28 Nov 2024 09:33:40 +0100	[thread overview]
Message-ID: <87zflj69ln.fsf@gnu.org> (raw)
In-Reply-To: <87zflkctrz.fsf@elephly.net> (Ricardo Wurmus's message of "Wed, 27 Nov 2024 21:21:20 +0100")

Hi,

Ricardo Wurmus <rekado@elephly.net> skribis:

> the CRAN updater downloads every upstream archive three times.  The
> importer memoizes calls to the download procedure, but one download that
> is out of reach is the very first.
>
> It is triggered by package-update/url-fetch in (guix upstream).  It uses
> download-to-store, which will unconditionally fetch whatever URL it is
> given.

Why three times (and not two)?

> I would very much like to parameterize download-to-store, so that we can
> optionally cache the results of its invocation.

I’m not sure exactly how to do that, but why not.

Another option would be to register GC roots (or mere symlinks) in
~/.cache for things that are downloaded, and then to use
‘If-Modified-Since’ plus some default TTL to determine whether to
re-download things.

HTH,
Ludo’.


  reply	other threads:[~2024-11-28  8:34 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-11-27 20:21 Caching calls to download-to-store? Ricardo Wurmus
2024-11-28  8:33 ` Ludovic Courtès [this message]
2024-11-28 10:21   ` Ricardo Wurmus
2024-11-29 15:31     ` Simon Tournier

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