I am preparing to install Guix System for the first time on my new computer by watching System Crafters’ youtube videos and reading Guix reference and other web pages. I’ve got a question about managing configuration files for Guix by git: How do you synchronize the Guix generations and git commit ID? In other words, if I know a Guix generation and want to know the corresponding git commit ID (or vice versa), how can I do so?
As far as I understand, Guix internally stores sufficient information to reproduce each generation of the system state and user profiles, and Guix can output configuration files and manifest files to do so. At the same time, it seems to be recommended to version-control the configuration files and manifest files for a user to edit and pass to guix system, guix home, guix package, etc. by git. However, I don’t find information about linking the two lines of history in Guix and git. Do people just don’t encounter an occasion to look up the git log for a particular Guix generation or track down a Guix generation while analyzing the git log about some issues?
I’m not sure if i understand what you mean, but you can get the commit hashes from your current system by running guix describe -f channels. That will output the information directly in scheme, which means you can literally just copy and paste that output into a file, put it into version control, and on a different machine run guix time-machine and point it to that file. One thing i recently found out about though since i’m quite new to guix myself is that if you usually do your guix pulling on one machine and then update your other machines with time machine, you should probably still run guix pull on those other machines first as well. I encountered an issue on my laptop, which i never ran guix pull on and instead just used time-machine, where it started complaining about my nonguix channel being unauthorized or something. running guix pull on my laptop solved the issue.
I want to clarify my question by taking this System Crafters’ webpage as an example.
Here the author recommends to put operating-system configuration file and home-environment configuration file as well as other files under ~/dotfiles directory and version-control them by git. These are files we, the users of our own machines, edit time to time to modify our system, install packages, etc.
To my understanding, guix describe -f channels outputs the git commit ID of the channels, such as guix and nonguix, managed by someone else than us, the users of the computers at hand. Which channels to be used are defined in ~/.config/guix/channels.scm by default.
Continuing with the example of System Crafters webpage above, and as far as I understand,
guix system reconfigure takes ~/dotfiles/config/systems/gemini.scmand other scm files as well as ~/.config/guix/channels.scm as input and outputs a new state of the operating system. Guix assigns a new generation number to this state. It records ~/dotfiles/config/systems/gemini.scmand other scm files as well as the git commit ID of the channels from which guix systemand other guix tools as well as packages were generated, so that the exact same system state can be re-created in the future or on another machine. However, Guix doesn’t record the git commit ID of ~/dotfiles/config/systems/gemini.scm and other config files under ~/dotfiles/ because it doesn’t know whether `~/dotfiles/` are under git version control.
Now, suppose that I find an issue in my ~/dotfiles/config/systems/gemini.scm at some point in time, and that I review the history of how I have edited this file with git. When I find a particular git commit ID at which a problematic code fragment was inserted, I may want to recreate the state of the system corresponding to this version of ~/dotfiles/config/systems/gemini.scm. However, the git commit ID of this version of this file is not recorded by Guix anywhere, and it’s not linked to the system generation number. I may need to track down the system generation number manually by taking date and other information as hints and by comparing the outputs of guix describe and git checkout. I wonder how people deal with this situation. I guess that they may have implemented a mechanism to link the git commit ID of system configuration files and system generation number automatically.