Hi Zimoun! Thank you for your detailed reply! You've given me something to chew on. In the meantime I wrote down everything I understood so far here: https://notabug.org/ZelphirKaltstahl/guix-package-manager-tutorials/src/master/guide.org
I'll try to get the "versions of packages from multiple GNU Guix commits" part done there as well. I also have another question: What is the best way to find out about until which commit id a package was available in a specific version? Is that website the only way, or is there a way from command line to search for the GNU Guix commit? Something like: ~~~~ guix search-guix-commit-for-package-with-version python-redis@3.3.8 --last --> Revision c7011ff850420fdbe1319b3d218bd362f2f9d618 guix search-guix-commit-for-package-with-version python-redis@3.3.8 --first --> Revision f5111b4d2b982d58387188bc3018e4dd2e9a9d4f ~~~~ or at least something only involving command line and not requiring me to bisect on GNU Guix commits ^^? Best regards, Zelphir On 10/10/20 6:44 PM, zimoun wrote: > Dear, > > On Sat, 10 Oct 2020 at 17:15, Zelphir Kaltstahl > <zelphirkaltst...@posteo.de> wrote: > >> For example, clicking leads to: >> >> http://data.guix.gnu.org/revision/f5111b4d2b982d58387188bc3018e4dd2e9a9d4f >> >> Here is where I am lost. Where do I need to click? > Click on one date. The row is: > > Version Output Builds From To > > and From mean the date of the first commit where the package is at the > version Version. > To is the date of the last commit. > > >> And this gives you the commit with 'python-redis@3.8', using the command: >> >> guix time-machine --commit=f5111b \ >> -- environment --ad-hoc python-redis python \ >> -- python >> >> OK, assume I get the commit id. >> >> I just tried this with the following command: >> >> ~~~~ >> guix time-machine --commit=f5111b -- environment --ad-hoc >> 'python-redis@3.3.8' 'python@3.8' -- python3.8 >> ~~~~ > Remove the '@X.Y'. It does not make sense since it is somehow already > included by the specification of the commit. > > >> My guess is, that in this commit of Guix there was no Python 3.8.2 yet? Or >> perhaps `python-redis` was not build for that Python version? > The "guix time-machine" gives you the exact same Guix as it was at the > commit specification. Therefore, since the commit f5111b provides the > version of python-redis you want, all the others do matter. > > >> I do not have a specific use-case at this moment, but I would like to know >> how to get those specific versions, the same every single time I run the >> command. To compare, when I create a virtual environment using: > As I have tried to explain. :-) > > In your project directory, you have to add 2 files about Guix: > > guix describe -f channels > channels.scm > > and the manifest.scm file containing the list of packages the project > requires. Then at any point in time, you can always do: > > guix time-machine -C channels.scm -- <subcommand> -m manifest <options> > > >> ~~~~ >> python3 -m venv venv >> source venv/bin/activate >> pip install --requirement requirements.txt >> ~~~~ > The issue with this approach is that somehow you need a SAT solver. > But that's another story. ;-) > > With Guix, AFAICT, the similar is: > - channels.scm which specifies a Guix version and so packages versions > - manifest.scm which specifies the list of packages. > > >> But that is, what I already have, isn't it? There is no part in this, that >> indicates `guix time-machine`. If time-machine is necessary to get the older >> version of python-redis@3.3.8 in the command line, then there must be >> something I need to write in the manifest.scm file to let Guix know, that I >> want a specific commit id. Or perhaps this is not possible with a manifest? >> Or is the idea, that I need to have a tracked channel as well to achieve it? > It is possible with the manifest but AFAIU it is a bit tricky and you > should write some Scheme. The easiest is using a channels.scm file. > See above. > > >> The other no-so-said is to track "guix describe", you *should* _track_ >> the file channels.scm: >> >> guix describe -f channels.scm >> >> OK this is probably the part, where I need to read the docs about it. I do >> not have a channels.scm and I do not know what does in there. I only have a >> vague idea about channels in my head. > Maybe with the output is easier to get the point. :-) > > --8<---------------cut here---------------start------------->8--- > $ guix describe -f channels > (list (channel > (name 'guix) > (url "https://git.savannah.gnu.org/git/guix.git";) > (commit > "a0d4aa2457d7e36012143ffe3fbc9dd4bc20ca4f") > (introduction > (make-channel-introduction > "9edb3f66fd807b096b48283debdcddccfea34bad" > (openpgp-fingerprint > "BBB0 2DDF 2CEA F6A8 0D1D E643 A2A0 6DF2 A33A 54FA"))))) > --8<---------------cut here---------------end--------------->8--- > > Basically, I have only one channel which is the official GNU Guix > "%default-channels". The important information here are: > > - url: from where it fetch > - commit: which checkout uses > > Therefore, "guix time-machine -C the/channel./file.scm -- help" will > fetch from url and restore at the commit. > > The other parts are important too. ;-) But not for your question. :-) > Well, basically you can even drop them and it will be fine. > > So yes, please go read the channel section. It has recently been > reordered to be more "understandable". Feedback is very welcome. :-) > > >> Then later or on another machine, you simply run the command: >> >> guix time-machine -C path/to/channels.scm \ >> -- <subcommand> -m path/to/manifest.scm <options> >> >> If I understand this correctly, a manifest with specific versions can only >> be guaranteed to work, if I track a channel as well. And somehow in that >> channel definition, I must specify which commit of Guix I am on? But >> wouldn't that limit my choice of libraries to what was available in one >> commit? > Yes, the same way the choice of libraries is limited at each commit state. :-) > > It is possible to mix libraries from different commits but the UI is > not as easy as it should be. > > For example, imagine you are doing: > > guix pull > guix install -m foo.scm /tmp/A > [...] # time flies > guix pull > guix install -m bar.scm /tmp/B > > And let assume that foo and bar are *not* coming from the same Guix > commit. You can still do: > > guix package --search-paths -p /tmp/A -p /tmp/B > > and therefore mix the two libraries. > > Well, using the time-machine, you need to track the commit which > provided foo and the one of bar. Then: > > guix time-machine --commit=commit-A -- install -m foo.scm -p /tmp/AA > guix time-machine --commit=commit-B -- install -m bar.scm -p /tmp/BB > > Then "guix package --search-paths -p /tmp/AA -p /tmp/BB" should > provide the exact same thing as before. > > That's why it is important to track the Guix commit (guix describe -f > channels) of software you are installing. Without this piece of > information, it is (almost) impossible to reinstall (other point in > time or space) the exact same version of the very software. > > Hope that helps, > simon -- repositories: https://notabug.org/ZelphirKaltstahl
