do-the-lix-thing

#!/usr/bin/env bash

################################################################################
# Initial setup
set -e # Exit immediately if a command exits with a non-zero status.
set -u # Treat unset variables as an error when substituting.
set -E # If set, the ERR trap is inherited by shell functions.
set -o pipefail # the return value of a pipeline is the status of
                # the last command to exit with a non-zero status,
                # or zero if no command exited with a non-zero status
################################################################################



################################################################################
# Constants
REPO_URL="https://github.com/samueldr/lix-gha-installer-action"
ACTION_NAME="Lix GHA Installer Action"
################################################################################


################################################################################
# Tracing
TRACE_LOG="trace.log"
ERR_LOG="err.log"
exec 4> $TRACE_LOG
exec 4> >( tee "$TRACE_LOG" >&4 )
exec 2> >( tee "$ERR_LOG" >&2 )
BASH_XTRACEFD=4
# For `set -x`, for tracing commands execution
PS4=" $ "
################################################################################

_gha_err() {
	local title
	title=$1; shift
	printf '\n::error title="%s"::%s\n' "$title" "${*//$'\n'/%0A}"
	printf '\nError:\n%s\n%s\n' "$title" "$*"
}

_handle_exit() {
	local status=$?
	if (( status )); then
		_gha_err "Unexpected failure..." "$(
			# NOTE: the error message is padded *a lot* to make sure it causes a "show more" expander to be present.
			echo "The $ACTION_NAME unexpectedly encountered a problem..."
			echo ""
			echo "Failure while executing the last command:"
			echo "  Exit status:"
			echo "    $status"
			echo "  Last commands from the trace log:"
			tail -n10 "$TRACE_LOG" | sed -e 's/^\s*\$\s*/    $ /'
			echo "  Last lines from the error log:"
			tail -n10 "$ERR_LOG" | sed -e 's/^/    stderr: /'
			_environment_details | sed -e 's/^/  /'
			echo ""
			echo "Please report this error to $REPO_URL/issues/new"
			echo ""
		)"
		exit $status
	else
		printf "Installation ran successfully to  the end!\n"
	fi
}

_exit_failure() {
	trap true EXIT
	exit 1
}

_command_exists() {
	type -P "$1" > /dev/null
}

_environment_details() {
	printf "Environment details:\n"
	printf "  - Date:     %s\n" "$(date)"
	printf "  - System:   %s\n" "$(_get_system)"
	printf "Operating system details:\n"
	(
	if _command_exists sw_vers; then
		sw_vers
	elif test -e /etc/lsb-release; then
		< /etc/lsb-release sed -e 's/=/: /'
	fi
	) | sed -e 's/^/  /'
}

_get_system() {
	local _arch
	local _os
	local _pair
	_arch=$(uname -m)
	_os=$(uname -s)
	_pair="$_os:$_arch"

	case "$_pair" in
		Linux:x86_64|Linux:aarch64)
			_os=linux
		;;
		Darwin:x86_64)
			_os=darwin
		;;
		Darwin:arm64)
			_os=darwin
			_arch=aarch64
		;;
		*)
			_gha_err "Unexpected OS or Architecture ($_pair)" "The OS '$_os' with architecture '$_arch' is not supported by the $ACTION_NAME at this time."
			_exit_failure
		;;
	esac
	printf "%s-%s" "$_arch" "$_os"
}

printf '»» lix-gha/do-the-lix-thing\n'
_get_system
printf '\n'
_environment_details
printf '\n'

trap _handle_exit EXIT

# Start tracing commands
# Doing it in a subshell means _handle_exit will not trace.
(
set -x

curl -sSf -L https://install.lix.systems/lix | bash -s -- install --no-confirm

(
	< /etc/nix/nix.conf sed -e 's/nixpkgs=flake:nixpkgs/nixpkgs=channel:nixos-unstable/'
	printf "trusted-users = root %s\n" "${USER:-}"
) > tmp.conf
sudo mv -v tmp.conf /etc/nix/nix.conf
)


printf '\nChecking install...\n'

# On macOS we're getting this:
# *sigh*
# /nix/var/nix/profiles/default/etc/profile.d/nix-daemon.sh: line 55: ZSH_VERSION: unbound variable
set +u

# Source the script once in subshell for trace logging...
# shellcheck disable=SC1091
(set -x; . /nix/var/nix/profiles/default/etc/profile.d/nix-daemon.sh)

# Then source for actual usage.
# shellcheck disable=SC1091
. /nix/var/nix/profiles/default/etc/profile.d/nix-daemon.sh

set -u

# Then do some additional checks
printf '\n  builtins.nixVersion: ';
(set -x; nix-instantiate --eval --json --strict --expr "(builtins.nixVersion)")
printf '\n'

rm -v "$TRACE_LOG" "$ERR_LOG" || true