install-nix-action/install-nix.sh
Sander 9c4488f07a
fix: set up the environment based on the installer shell scripts
The installer scripts would normally set up the various environment variables that Nix needs.
Since GitHub doesn't run any profile or rc scripts by default, we need to set these up ourselves.
2025-08-29 01:09:29 +02:00

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#!/usr/bin/env bash
set -euo pipefail
if nix_path="$(type -p nix)" ; then
echo "Aborting: Nix is already installed at ${nix_path}"
exit
fi
if [[ ($OSTYPE =~ linux) && ($INPUT_ENABLE_KVM == 'true') ]]; then
enable_kvm() {
echo 'KERNEL=="kvm", GROUP="kvm", MODE="0666", OPTIONS+="static_node=kvm"' | sudo tee /etc/udev/rules.d/99-install-nix-action-kvm.rules
sudo udevadm control --reload-rules && sudo udevadm trigger --name-match=kvm
}
echo '::group::Enabling KVM support'
enable_kvm && echo 'Enabled KVM' || echo 'KVM is not available'
echo '::endgroup::'
fi
# GitHub command to put the following log messages into a group which is collapsed by default
echo "::group::Installing Nix"
# Create a temporary workdir
workdir=$(mktemp -d)
trap 'rm -rf "$workdir"' EXIT
# Configure Nix
add_config() {
echo "$1" >> "$workdir/nix.conf"
}
add_config "show-trace = true"
# Set jobs to number of cores
add_config "max-jobs = auto"
# TODO: is this still necessary if we set NIX_SSL_CERT_FILE below?
if [[ $OSTYPE =~ darwin ]]; then
add_config "ssl-cert-file = /etc/ssl/cert.pem"
fi
# Allow binary caches specified at user level
if [[ $INPUT_SET_AS_TRUSTED_USER == 'true' ]]; then
add_config "trusted-users = root ${USER:-}"
fi
# Add a GitHub access token.
# Token-less access is subject to lower rate limits.
if [[ -n "${INPUT_GITHUB_ACCESS_TOKEN:-}" ]]; then
echo "::debug::Using the provided github_access_token for github.com"
add_config "access-tokens = github.com=$INPUT_GITHUB_ACCESS_TOKEN"
# Use the default GitHub token if available.
# Skip this step if running an Enterprise instance. The default token there does not work for github.com.
elif [[ -n "${GITHUB_TOKEN:-}" && $GITHUB_SERVER_URL == "https://github.com" ]]; then
echo "::debug::Using the default GITHUB_TOKEN for github.com"
add_config "access-tokens = github.com=$GITHUB_TOKEN"
else
echo "::debug::Continuing without a GitHub access token"
fi
# Append extra nix configuration if provided
if [[ -n "${INPUT_EXTRA_NIX_CONFIG:-}" ]]; then
add_config "$INPUT_EXTRA_NIX_CONFIG"
fi
if [[ ! $INPUT_EXTRA_NIX_CONFIG =~ "experimental-features" ]]; then
add_config "experimental-features = nix-command flakes"
fi
# Always allow substituting from the cache, even if the derivation has `allowSubstitutes = false`.
# This is a CI optimisation to avoid having to download the inputs for already-cached derivations to rebuild trivial text files.
if [[ ! $INPUT_EXTRA_NIX_CONFIG =~ "always-allow-substitutes" ]]; then
add_config "always-allow-substitutes = true"
fi
# Nix installer flags
installer_options=(
--no-channel-add
--nix-extra-conf-file "$workdir/nix.conf"
)
# Enable daemon on macOS and Linux systems with systemd, unless --no-daemon is specified
if [[ (! $INPUT_INSTALL_OPTIONS =~ "--no-daemon") && ($OSTYPE =~ darwin || -e /run/systemd/system) ]]; then
use_daemon() { true; }
else
use_daemon() { false; }
fi
if use_daemon; then
installer_options+=(
--daemon
--daemon-user-count "$(python3 -c 'import multiprocessing as mp; print(mp.cpu_count() * 2)')"
)
else
# "fix" the following error when running nix*
# error: the group 'nixbld' specified in 'build-users-group' does not exist
add_config "build-users-group ="
sudo mkdir -p /etc/nix
sudo chmod 0755 /etc/nix
sudo cp "$workdir/nix.conf" /etc/nix/nix.conf
fi
if [[ -n "${INPUT_INSTALL_OPTIONS:-}" ]]; then
IFS=' ' read -r -a extra_installer_options <<< "$INPUT_INSTALL_OPTIONS"
installer_options=("${extra_installer_options[@]}" "${installer_options[@]}")
fi
echo "installer options: ${installer_options[*]}"
# There is --retry-on-errors, but only newer curl versions support that
curl_retries=5
nix_version=2.31.0
while ! curl -sS -o "$workdir/install" -v --fail -L "${INPUT_INSTALL_URL:-https://releases.nixos.org/nix/nix-${nix_version}/install}"
do
sleep 1
((curl_retries--))
if [[ $curl_retries -le 0 ]]; then
echo "curl retries failed" >&2
exit 1
fi
done
sh "$workdir/install" "${installer_options[@]}"
# Configure the environment
#
# Adapted from the single- and multi-user scripts:
# single-user: https://github.com/NixOS/nix/blob/master/scripts/nix-profile-daemon.sh.in
# multi-user: https://github.com/NixOS/nix/blob/master/scripts/nix-profile-daemon.sh.in
#
# These scripts would normally be evaluated as part of the user's shell profile.
# GitHub doesn't evaluate profiles or rc scripts by default, so we set up the environment manually.
echo "::debug::Nix installed, setting up environment"
# Export the path to Nix
if [[ -n "${INPUT_NIX_PATH:-}" ]]; then
echo "NIX_PATH=${INPUT_NIX_PATH}" >> "$GITHUB_ENV"
fi
# Set temporary directory if not already set
# Fixes https://github.com/cachix/install-nix-action/issues/197
if [[ -z "${TMPDIR:-}" ]]; then
echo "TMPDIR=${RUNNER_TEMP}" >> "$GITHUB_ENV"
fi
# Determine NIX_LINK path (XDG spec, newer XDG-compliant, or legacy)
if [[ -n "${XDG_STATE_HOME:-}" && -e "$XDG_STATE_HOME/nix/profile" ]]; then
NIX_LINK="$XDG_STATE_HOME/nix/profile"
elif [[ -e "$HOME/.local/state/nix/profile" ]]; then
NIX_LINK="$HOME/.local/state/nix/profile"
else
NIX_LINK="$HOME/.nix-profile"
fi
# Set Nix profiles
echo "NIX_PROFILES=/nix/var/nix/profiles/default $NIX_LINK" >> "$GITHUB_ENV"
# Set NIX_SSL_CERT_FILE if not already configured
if [[ -z "${NIX_SSL_CERT_FILE:-}" ]]; then
# Check common SSL certificate file locations
if [[ -f "/etc/ssl/certs/ca-certificates.crt" ]]; then # NixOS, Ubuntu, Debian, Gentoo, Arch
echo "NIX_SSL_CERT_FILE=/etc/ssl/certs/ca-certificates.crt" >> "$GITHUB_ENV"
elif [[ $OSTYPE =~ darwin && -f "/etc/ssl/cert.pem" ]]; then # macOS
echo "NIX_SSL_CERT_FILE=/etc/ssl/cert.pem" >> "$GITHUB_ENV"
elif [[ -f "/etc/ssl/ca-bundle.pem" ]]; then # openSUSE Tumbleweed
echo "NIX_SSL_CERT_FILE=/etc/ssl/ca-bundle.pem" >> "$GITHUB_ENV"
elif [[ -f "/etc/ssl/certs/ca-bundle.crt" ]]; then # Old NixOS
echo "NIX_SSL_CERT_FILE=/etc/ssl/certs/ca-bundle.crt" >> "$GITHUB_ENV"
elif [[ -f "/etc/pki/tls/certs/ca-bundle.crt" ]]; then # Fedora, CentOS
echo "NIX_SSL_CERT_FILE=/etc/pki/tls/certs/ca-bundle.crt" >> "$GITHUB_ENV"
elif [[ -f "/usr/local/share/certs/ca-root-nss.crt" ]]; then # FreeBSD
echo "NIX_SSL_CERT_FILE=/usr/local/share/certs/ca-root-nss.crt" >> "$GITHUB_ENV"
elif [[ -f "/etc/pki/tls/cacert.pem" ]]; then # OpenELEC
echo "NIX_SSL_CERT_FILE=/etc/pki/tls/cacert.pem" >> "$GITHUB_ENV"
elif [[ -f "/nix/var/nix/profiles/default/etc/ssl/certs/ca-bundle.crt" ]]; then # fall back to cacert in default Nix profile
echo "NIX_SSL_CERT_FILE=/nix/var/nix/profiles/default/etc/ssl/certs/ca-bundle.crt" >> "$GITHUB_ENV"
elif [[ -f "$NIX_LINK/etc/ssl/certs/ca-bundle.crt" ]]; then # fall back to cacert in user Nix profile
echo "NIX_SSL_CERT_FILE=$NIX_LINK/etc/ssl/certs/ca-bundle.crt" >> "$GITHUB_ENV"
fi
fi
# Set paths based on the installation type
if use_daemon; then
# Multi-user daemon install - add both paths
echo "/nix/var/nix/profiles/default/bin" >> "$GITHUB_PATH"
fi
# Always add the user profile path
echo "$NIX_LINK/bin" >> "$GITHUB_PATH"
# Close the log message group which was opened above
echo "::endgroup::"