From debbugs-submit-bounces@debbugs.gnu.org Sun Aug 23 12:21:15 2020 Received: (at 42162) by debbugs.gnu.org; 23 Aug 2020 16:21:15 +0000 Received: from localhost ([127.0.0.1]:54977 helo=debbugs.gnu.org) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1k9sk6-0006kl-NI for submit@debbugs.gnu.org; Sun, 23 Aug 2020 12:21:14 -0400 Received: from eggs.gnu.org ([209.51.188.92]:54288) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1k9sk5-0006kV-RF for 42162@debbugs.gnu.org; Sun, 23 Aug 2020 12:21:14 -0400 Received: from fencepost.gnu.org ([2001:470:142:3::e]:55390) by eggs.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1k9sjz-0001SL-Vt; Sun, 23 Aug 2020 12:21:07 -0400 Received: from [2a01:e0a:1d:7270:af76:b9b:ca24:c465] (port=38296 helo=ribbon) by fencepost.gnu.org with esmtpsa (TLS1.2:RSA_AES_256_CBC_SHA1:256) (Exim 4.82) (envelope-from ) id 1k9sjz-000278-FU; Sun, 23 Aug 2020 12:21:07 -0400 From: =?utf-8?Q?Ludovic_Court=C3=A8s?= To: Timothy Sample Subject: Re: bug#42162: Recovering source tarballs References: <87mu4iv0gc.fsf@inria.fr> <86h7uq8fmk.fsf@gmail.com> <87d05etero.fsf@gnu.org> <87r1tit5j6.fsf_-_@gnu.org> <875za4ykej.fsf@ngyro.com> <87bljvu4p4.fsf@gnu.org> <87d047u0l3.fsf@ngyro.com> <87wo2dnhgb.fsf@gnu.org> <874kpgudic.fsf@ngyro.com> X-URL: http://www.fdn.fr/~lcourtes/ X-Revolutionary-Date: 7 Fructidor an 228 de la =?utf-8?Q?R=C3=A9volution?= X-PGP-Key-ID: 0x090B11993D9AEBB5 X-PGP-Key: http://www.fdn.fr/~lcourtes/ludovic.asc X-PGP-Fingerprint: 3CE4 6455 8A84 FDC6 9DB4 0CFB 090B 1199 3D9A EBB5 X-OS: x86_64-pc-linux-gnu Date: Sun, 23 Aug 2020 18:21:05 +0200 In-Reply-To: <874kpgudic.fsf@ngyro.com> (Timothy Sample's message of "Wed, 05 Aug 2020 14:57:31 -0400") Message-ID: <87r1rxbafi.fsf@gnu.org> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/26.3 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable X-Spam-Score: -2.3 (--) X-Debbugs-Envelope-To: 42162 Cc: 42162@debbugs.gnu.org, Maurice =?utf-8?Q?Br=C3=A9mond?= , zimoun X-BeenThere: debbugs-submit@debbugs.gnu.org X-Mailman-Version: 2.1.18 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: debbugs-submit-bounces@debbugs.gnu.org Sender: "Debbugs-submit" X-Spam-Score: -3.3 (---) Hello! Timothy Sample skribis: >> If we expose the database over HTTP (like over cgit), we can arrange so >> that (guix download) simply GETs db.example.org/sha256/xyz. No need to >> fetch the whole database. >> >> It might be more reasonable to have a real database and a real service >> around it, I=E2=80=99m sure Chris Baines would agree ;-), but we can cho= ose URLs >> that could easily be implemented by a =E2=80=9Creal=E2=80=9D service ins= tead of cgit in >> the future. > > I got it working over cgit shortly after sending my last message. :) So > far, I am very much on team =E2=80=9Cgood enough for now=E2=80=9D. Wonderful. :-) >> Timothy Sample skribis: >> >>> I was imagining an escape hatch beyond this, where one could look up a >>> provenance record from when Disarchive ingested and verified a source >>> code archive. The provenance record would tell you which version of >>> Guix was used when saving the archive, so you could try your luck with >>> using =E2=80=9Cguix time-machine=E2=80=9D to reproduce Disarchive=E2=80= =99s original >>> computation. If we perform database migrations, you would need to >>> travel back in time in the database, too. The idea is that you could >>> work around breakages in Disarchive automatically using the Power of >>> Guix=E2=84=A2. Just a stray thought, really. >> >> Seems to me it Shouldn=E2=80=99t Be Necessary? :-) >> >> I mean, as long as the format is extensible and =E2=80=9Cfuture-proof=E2= =80=9D, we=E2=80=99ll >> always be able to rebuild tarballs and then re-disassemble them if we >> need to compute new hashes or whatever. > > If Disarchive relies on external compressors, there=E2=80=99s an outside = chance > that those compressors could change under our feet. In that case, one > would want to be able to track down exactly which version of XZ was used > when Disarchive verified that it could reassemble a given source > archive. Oh, true. Gzip and bzip2 are more-or-less =E2=80=9Cset in stone=E2=80=9D, = but xz, lzip, or zstd could change. Recording the exact version of the implementation would be a good stopgap. > Maybe I=E2=80=99m being paranoid, but if the database entries are being > computed by the CI infrastructure it would be pretty easy to note the > Guix commit just in case. Yeah, that makes sense. At least we could have =E2=80=9Cnotes=E2=80=9D in = the file format to store that kind of info. Using CI is also a good idea. >> I was thinking that it might be best to not use Guix for computations. >> For example, have =E2=80=9Cdisarchive save=E2=80=9D not build derivation= s and instead do >> everything =E2=80=9Chere and now=E2=80=9D. That would make it easier fo= r others to >> adopt. Wait, looking at the Git history, it looks like you already >> addressed that point, neat. :-) > > Since my last message I managed to remove Guix as dependency completely. > Right now it loads =E2=80=98(guix swh)=E2=80=99 opportunistically, but I = might just copy > the code in. Directory references now support multiple =E2=80=9Caddresse= s=E2=80=9D so > that you could have Nix-style, SWH-style, IPFS-style, etc. Hopefully my > next message will have a WIP patch enabling Guix to use Disarchive! Neat, looking forward to it! Thank you, Ludo=E2=80=99.