Title: NixOS Bento: now able to compare local and remote NixOS version
Author: Solène
Date: 06 September 2022
Tags: bento nixos nix
Description:
# Bento
Project update: the report is now able to compare if the remote server
is using the NixOS version we built locally. This is possible as NixOS
builds are reproducible, I get the same result on the server and the
remote system.
The tool is getting in a better shape, the code received extra checks
in a lot of place.
A bit later (blog post update), I added the possibility to trigger the
update from the user.
HTML Bento git project repository
# Listening to socket
With systemd it's possible to trigger a command upon connecting on a
socket, I made bento systemd service to listen on port TCP/51337, a
connection would start the service "bento-update.service", and display
the output to the TCP client.
This totally works in the web browser, it's now possible to create a
bookmark that just starts the update and give instant feedback about
the update process. This will be particularly useful in case of a
debug phone session to ask the remote person to trigger an update on
their side instead of waiting for a timer.
# Status display demo
It is now possible to differenciate the "not up to date" state into two
categories:
* the bento scripts were updated but not NixOS version change, this is
called "sync pending". Changes could be distributing the updating file
to give a new address for the remote server, so we can ensure they all
received it.
* the local NixOS version differs from the remote version, a rebuild is
required, thus it's called "rebuild pending"
The "sync pending" is very fast, it only need to copy the files, but
won't rebuild anything.
```text
machine local version remote version state time
------- --------- ----------- ------------- ----
kikimora 996vw3r6 996vw3r6 💚 sync pending 🚩 (build 5m 53s) (new config 2m 48s)
nas r7ips2c6 lvbajpc5 🛑 rebuild pending 🚩 (build 5m 49s) (new config 1m 45s)
t470 ih7vxijm ih7vxijm 💚 up to date 💚 (build 2m 24s)
x1 fcz1s2yp fcz1s2yp 💚 up to date 💚 (build 2m 37s)
```