website: Update draft post about the Guile guix-daemon.
* website/drafts/guile-guix-daemon-introduction.md: Update.
This commit is contained in:
Christopher Baines
parent
048aba8eac
commit
d33bbe1063
|
|
@ -1,26 +1,29 @@
|
|||
title: Building a Guile guix-daemon
|
||||
title: A build daemon in Guile
|
||||
author: Christopher Baines
|
||||
tags:
|
||||
tags: Guix Daemon
|
||||
date: 2023-10-13 14:30:00
|
||||
---
|
||||
|
||||
When using Guix, you might be aware of the
|
||||
[daemon](https://guix.gnu.org/en/manual/en/html_node/Setting-Up-the-Daemon.html).
|
||||
It runs in the background but it's a key component in Guix. Whenever
|
||||
you've been using Guix to operate on the store, whether that's
|
||||
building something or downloading some substitutes, it's the daemon
|
||||
managing that operation.
|
||||
you've been using Guix to [operate on the store](https://guix.gnu.org/en/blog/2023/dissecting-guix-part-1-derivations/),
|
||||
whether that's building something or downloading some substitutes,
|
||||
it's the daemon managing that operation.
|
||||
|
||||
The daemon also is a key part of the history of Guix. The Guix
|
||||
project started mixing Guile with ideas from the Nix project, and the
|
||||
guix-daemon is a fork of the nix-dameon with some tweaks made over the
|
||||
years. Rather than being implemented in Guile though, the daemon is
|
||||
implemented in C++. Given the focus on Guile in Guix, this is
|
||||
unusual, and I believe it's made working on the daemon less desirable,
|
||||
especially since rewriting it in Guile has been discussed for many
|
||||
years now.
|
||||
`guix-daemon` is a fork of the `nix-daemon` with some tweaks made over
|
||||
the years. Rather than being implemented in Guile though, the daemon
|
||||
is implemented in C++ with some helpers written in Guile. Given the
|
||||
focus on Guile in Guix, this is unusual, and I believe it's made
|
||||
working on the daemon less desirable, especially since rewriting it in
|
||||
Guile has been discussed for many years now. It has been the topic of
|
||||
a Google Summer of Code internship by Caleb Ristvedt back in 2017,
|
||||
which helped clarify implementation details and led to some
|
||||
[preliminary code](https://git.savannah.gnu.org/cgit/guix.git/log/?h=guile-daemon).
|
||||
|
||||
# What would a Guile guix-dameon mean?
|
||||
# What would a build daemon in Guile bring?
|
||||
|
||||
Guix already has code written in Guile for doing some of what the
|
||||
daemon does internally, so being able to use this Guile code inside
|
||||
|
|
@ -30,51 +33,56 @@ code.
|
|||
There isn't Guile code yet for everything the daemon does though, so
|
||||
getting to this point will make new exciting features easier to
|
||||
implement. That could be things like making it easier to use Guix in
|
||||
environments where running the dameon in the usual way is inconvinient
|
||||
environments where running the daemon in the usual way is inconvenient
|
||||
or infeasible. It may also help with portability, so help with
|
||||
running Guix on the Hurd and new architectures.
|
||||
|
||||
As someone who's more experienced writing Guile than C++, I'm also
|
||||
hoping it'll generally make hacking on the dameon more accessible.
|
||||
hoping it'll generally make hacking on the daemon more accessible.
|
||||
This in turn might lead to new features. For example, I think having
|
||||
a Guile guix-daemon will simplify implementing a way to jump in to a
|
||||
build and inspect the environment.
|
||||
a build daemon written in Guile will simplify implementing a way to
|
||||
jump in to a build and inspect the environment.
|
||||
|
||||
With some [monetary support from NLNet](https://nlnet.nl/project/GuixDaemon-Guile/),
|
||||
I'm planning to focus for the next year on getting a Guile
|
||||
implementation of the guix-daemon written and adopted.
|
||||
With that in mind, I'm excited to announce that [support from
|
||||
NLNet](https://nlnet.nl/project/GuixDaemon-Guile/), will allow me to
|
||||
focus for the next year on getting a Guile implementation of the build
|
||||
daemon written and adopted.
|
||||
|
||||
# A technical plan
|
||||
|
||||
Building on the [recent discussion](https://lists.gnu.org/archive/html/guix-devel/2023-09/msg00328.html)
|
||||
of this topic on the guix-devel mailing list, here's some technical
|
||||
thoughts on how I'm approaching this.
|
||||
of this topic on the `guix-devel@gnu.org` mailing list, here's some
|
||||
technical thoughts on how I'm approaching this.
|
||||
|
||||
While I think there's a substantial amount of work to do, progress
|
||||
towards a Guile guix-daemon has already been made. Given that things
|
||||
in Guix have probably changed since this work has happened, I plan to
|
||||
carefully review that existing work (most of which can be found on the
|
||||
`guile-daemon` branch) so that I can build upon it.
|
||||
[`guile-daemon` branch](https://git.savannah.gnu.org/cgit/guix.git/log/?h=guile-daemon)
|
||||
|
||||
The priority for the Guile daemon is backwards compatability, so the
|
||||
The priority for the Guile daemon is backwards compatibility, so the
|
||||
plan is to allow switching between the C++ implementation and Guile
|
||||
implementation which any issues. This'll require not making changes
|
||||
to the database schema, and generally doing things in a way which the
|
||||
current C++ daemon will understand.
|
||||
|
||||
Like the build coordinator, I'm planning to make the daemon a single
|
||||
process using Guile Fibers for parallelism. This is in contrast to
|
||||
the forking model using by the C++ daemon. Even though it's not a
|
||||
priority to address feature issues with the current dameon, this
|
||||
approach might help to reduce database contention issues experienced
|
||||
with the current daemon, and allow for less locking, like not having
|
||||
the big GC lock for example.
|
||||
|
||||
# Progress reports
|
||||
Like the [Guix Build Coordinator](https://guix.gnu.org/en/blog/2021/building-derivations-how-complicated-can-it-be/),
|
||||
I'm planning to make the daemon a single process using
|
||||
[Fibers](https://github.com/wingo/fibers) for concurrency. This is in
|
||||
contrast to the forking model using by the C++ daemon. Even though
|
||||
it's not a priority to address feature issues with the current daemon,
|
||||
this approach might help to reduce database contention issues
|
||||
experienced with the current daemon, and allow for less locking, like
|
||||
not having the big GC lock for example.
|
||||
|
||||
I'm planning on publishing more blog posts as the project progress, so
|
||||
keep an eye on the Guix blog for future updates.
|
||||
|
||||
# Acknowledgments
|
||||
|
||||
Thanks to Simon Tournier and Ludovic Courtès for providing feedback on
|
||||
an earlier draft of this post.
|
||||
|
||||
#### About GNU Guix
|
||||
|
||||
[GNU Guix](https://guix.gnu.org) is a transactional package manager
|
||||
|
|
|
|||
Loading…
Reference in New Issue