guix-explorer

GNU Guix System Explorer

“What’s this?”, you ask. It’s a hack, initially written for a FOSDEM 2021 talk, that allows you to navigate the services of your Guix System configuration and the connections among them.

Exploring your system

It’s very bare-bones, my friend! Assuming the Guix modules are in your GUILE_LOAD_PATH—it’s the case on Guix System—you can run, say:

./explore.scm /run/current-system/configuration.scm

That spawns a web server on port 8080, which you can talk to from your browser at http://localhost:8080. And what do you see there?

Voilà!

What is this showing?

If you’ve tried guix system extension-graph before, it is showing something similar. On the graph displayed, each node represents a service of your system configuration, and each edge represents a service extension. Essential services are shown as red circles, “base” services are represented as smaller red circles, and user services are smaller gray circles. When hovering over a service, its documentation is displayed at the top left.

When clicking on a service, its value gets displayed. For example, the value of the udev service is a record containing (1) the (e)udev package it uses, and (2) the set of udev rules. For the openssh service, the value is a record listing the various sshd options.

The graph shows, for example, an arrow from the openssh to the accounts service, which is responsible for setting up user accounts. When clicking on this arrow, we see the “value” that openssh contributes to accounts: it’s a list consisting of the sshd group and the sshd user account—the “privilege separation” account used by sshd.

Last, when double-clicking on a service, you can see the effect of folding all the services that contribute to it. For example, when double-clicking on shepherd-root, all the services with an incoming edge contribute a value to this service—a Shepherd service—and are no longer displayed. At this point, clicking on shepherd-root shows its new value: a list of shepherd-service records.

Ultimately, all services can be folded into system, which the the “root” of all services, representing the final, assembled operating system.

Why?

Modern GNU/Linux distributions are complex beasts and it’s hard to get the big picture. This tool aims to help users answer questions such as: What components make up my system? How are they composed together? How does the high-level configuration of a service translate into the configuration of lower-level services?

Ultimately, I would like to think of this tool not just as a helper for Guix System users, but also as an educational tool—a tool to help users and enthusiasts learn how things are glued together. It’s about empowering users, reducing the gap between “those who know” and “those who use”.

What’s next?

Who knows what’s next! There are certainly glitches here and there in the user interface that could be fixed, and convenience features that could be added. Perhaps this tool could be made part of Guix proper, as a new guix system explore sub-command?

So far the tool is only about exploring the system. What if we allowed users to edit their system configuration right from the user interface? Food for thought!

Join us!

Things you can do:

• Watch the accompanying FOSDEM 2021 talk, Declaratively Yours—Composing system abstractions with GNU Guix.
• Try it yourself, and hack it!
• Get in touch with Guix!
  

Ludovic Courtès, February 2021.