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+---
+title: Guix inside sourcehut builds.sr.ht CI
+date: 2020-08-10
+layout: post
+lang: en
+ref: guix-sourcehut-ci
+---
+After the release of the [NixOS images in builds.sr.ht][0] and much
+usage of it, I also started looking at [Guix][1] and
+wondered if I could get it on the awesome builds.sr.ht service.
+
+[0]: https://man.sr.ht/builds.sr.ht/compatibility.md#nixos
+[1]: https://guix.gnu.org/
+
+The Guix manual section on the [binary installation][2] is very thorough, and
+even a [shell installer script][3] is provided, but it is built towards someone
+installing Guix on their personal computer, and relies heavily on interactive
+input.
+
+[2]: https://guix.gnu.org/manual/en/guix.html#Binary-Installation
+[3]: https://git.savannah.gnu.org/cgit/guix.git/plain/etc/guix-install.sh
+
+I developed the following set of scripts that I have been using for some time to
+run Guix tasks inside builds.sr.ht jobs. First, `install-guix.sh`:
+
+```shell
+#!/usr/bin/env bash
+set -x
+set -Eeuo pipefail
+
+VERSION='1.0.1'
+SYSTEM='x86_64-linux'
+BINARY="guix-binary-${VERSION}.${SYSTEM}.tar.xz"
+
+cd /tmp
+wget "https://ftp.gnu.org/gnu/guix/${BINARY}"
+tar -xf "${BINARY}"
+
+sudo mv var/guix /var/
+sudo mv gnu /
+sudo mkdir -p ~root/.config/guix
+sudo ln -fs /var/guix/profiles/per-user/root/current-guix ~root/.config/guix/current
+
+GUIX_PROFILE="$(echo ~root)/.config/guix/current"
+source "${GUIX_PROFILE}/etc/profile"
+
+groupadd --system guixbuild
+for i in $(seq -w 1 10);
+do
+  useradd -g guixbuild                       \
+          -G guixbuild                       \
+          -d /var/empty                      \
+          -s "$(command -v nologin)"         \
+          -c "Guix build user ${i}" --system \
+          "guixbuilder${i}";
+done
+
+mkdir -p /usr/local/bin
+cd /usr/local/bin
+ln -s /var/guix/profiles/per-user/root/current-guix/bin/guix .
+ln -s /var/guix/profiles/per-user/root/current-guix/bin/guix-daemon .
+
+guix archive --authorize < ~root/.config/guix/current/share/guix/ci.guix.gnu.org.pub
+```
+
+Almost all of it is taken directly from the [binary installation][2] section
+from the manual, with the interactive bits stripped out: after downloading and
+extracting the Guix tarball, we create some symlinks, add guixbuild users and
+authorize the `ci.guix.gnu.org.pub` signing key.
+
+After installing Guix, we perform a `guix pull` to update Guix inside `start-guix.sh`:
+```shell
+#!/usr/bin/env bash
+set -x
+set -Eeuo pipefail
+
+sudo guix-daemon --build-users-group=guixbuild &
+guix pull
+guix package -u
+guix --version
+```
+
+Then we can put it all together in a sample `.build.yml` configuration file I'm
+using myself:
+
+```yaml
+image: debian/stable
+packages:
+  - wget
+sources:
+  - https://git.sr.ht/~euandreh/songbooks
+tasks:
+  - install-guix: |
+      cd ./songbooks/
+      ./scripts/install-guix.sh
+      ./scripts/start-guix.sh
+      echo 'sudo guix-daemon --build-users-group=guixbuild &' >> ~/.buildenv
+      echo 'export PATH="${HOME}/.config/guix/current/bin${PATH:+:}$PATH"' >> ~/.buildenv
+  - tests: |
+      cd ./songbooks/
+      guix environment -m build-aux/guix.scm -- ./scripts/run-all-tests.sh || echo -e '\033[1;31mFAILED BUILD\033[0m'
+  - docs: |
+      cd ./songbooks/
+      guix environment -m build-aux/guix.scm -- ./scripts/build-documentation.sh
+      ./scripts/publish-documentation.sh
+```
+
+We have to add the `guix-daemon` to `~/.buildenv` so it can be started on every
+following task run. Also, since we used `wget` inside `install-guix.sh`, we had
+to add it to the images package list.
+
+After the `install-guix` task, you can use Guix to build and test your project,
+or run any `guix environment --ad-hoc my-package -- my script` :)
+
+## Improvements
+
+When I originally created this code I had a reason why to have both a `sudo`
+call for `sudo ./scripts/install-guix.sh` and `sudo` usages inside
+`install-guix.sh` itself. I couldn't figure out why (it feels like my past self
+was a bit smarter xD), but it feels ugly now. If it is truly required I could
+add an explanation for it, or remove this entirely in favor of a more elegant solution.
+
+I could also contribute the Guix image upstream to builds.sr.ht, but there
+wasn't any build or smoke tests in the original [repository][4], so I wasn't
+inclined to make something that just "works on my machine" or add a maintainence
+burden to the author. I didn't look at it again recently, though.
+
+[4]: https://git.sr.ht/~sircmpwn/builds.sr.ht