Add local.sh script to update local machine

Yes there is nixos-rebuild but this turns out to be for me much more
handy when updating and testing system.

4 files changed, 221 insertions, 120 deletions

diff --git a/.gitignore b/.gitignore
index fcfc4a1..fd1b4ea 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1 +1,2 @@
 result*
+.result-*
diff --git a/common.sh b/common.sh
new file mode 100644
index 0000000..995a57e
--- /dev/null
+++ b/common.sh
@@ -0,0 +1,157 @@
+# Common Bash functions for helper scripts in this repository
+set -eu
+
+## Logging #####################################################################
+_print() {
+	local color="\e[$1m"
+	local clrcolor="\e[0m"
+	shift
+	if [ ! -t 1 ]; then
+		color=""
+		clrcolor=""
+	fi
+	printf "${color}%s${clrcolor}\n" "$*" >&2
+}
+
+stage() {
+	_print '1;32' "$@"
+}
+
+info() {
+	_print '1;35' "$@"
+}
+
+error() {
+	_print '1;31' "$@"
+}
+warning() {
+	_print '1;33' "$@"
+}
+
+## SSH access helper ###########################################################
+
+# Convert hostname to the SSH destination
+sshdest() {
+	awk -F- 'NF > 1 { print $2"."$1; exit } { print $1 }' <<<"$1"
+}
+
+_ssh() {
+	local device="$1"
+	shift
+	if [ "$device" != "$(hostname)" ]; then
+		local -a args
+		[ "$1" = "sudo" ] && \
+			args+=('-t') # Crude detection for terminal need
+		ssh "${args[@]}" "$(sshdest "$device")" -- "$@"
+	else
+		"$@"
+	fi
+}
+
+## Evalutions and queries ######################################################
+
+# The path where build result is linked to
+result() {
+	echo ".result-$1"
+}
+
+# Get system of the device
+device_system() {
+	nix eval --raw ".#nixosConfigurations.$1.config.nixpkgs.system"
+}
+
+# Validates if link is valid.
+build_validate() {
+	local device="$1"
+	[ -L "$(result "$device")" ] && [ -e "$(result "$device")" ]
+}
+
+## Build NixOS system ##########################################################
+# $1: device name
+# All other arguments are passed to the nix build command
+build() {
+	local device="$1"
+	shift
+
+	local toplevel=".config.system.build.toplevel"
+	if [ "$(device_system "$device")" = "armv7l-linux" ]; then
+		toplevel=".config.system.build.cross.x86_64-linux${toplevel}"
+	fi
+
+	stage "Building system for device: $device"
+	nix build \
+		-o "$(result "${device}")" \
+		--keep-going \
+		"$@" \
+		"${0%/*}#nixosConfigurations.${device}${toplevel}"
+}
+
+## Copy NixOS system ###########################################################
+# $1: device name
+copy() {
+	local device="$1"
+	if ! build_validate "$device"; then
+		warning "System for device '$device' seems to be not build." >&2
+		return 1
+	fi
+	local store
+	store="$(readlink -f "$(result "$device")")"
+
+	local freespace required;
+	freespace="$(_ssh "$device" df -B 1 /nix | awk 'NR == 2 { print $4 }')"
+	required="$(nix path-info -S "$store" | awk '{ print $2 }')"
+	info "Free space on device: $(numfmt --to=iec "$freespace")"
+	info "Required space: $(numfmt --to=iec "$required")"
+	if [ "$required" -ge "$freespace" ]; then
+		error "There is not enough space to copy clousure to: $device" >&2
+		return 1
+	fi
+
+	stage "Copy closure to: $device"
+	nix copy -s --to "ssh://$(sshdest "$device")" "$store"
+}
+
+## Switch Nix encironment ######################################################
+# $1: switch operation to be performed
+# $2: device name
+# TODO possibly really query if switch is or is not required
+setenv() {
+	local switchop="$1"
+	local device="$2"
+	if ! build_validate "$device"; then
+		warning "System '$device' seems to be not build." >&2
+		return 1
+	fi
+	local store
+	store="$(readlink -f "$(result "$device")")"
+
+	stage "${switchop^} system: $device"
+	local cursystem
+	cursystem="$(_ssh "$device" readlink -f /nix/var/nix/profiles/system)"
+	if [ "$cursystem" != "$store" ]; then
+		info "-----------------------------------------------------------------"
+		_ssh "$device" \
+			nix store diff-closures "$cursystem" "$store"
+		info "-----------------------------------------------------------------"
+		# TODO we should call here switch-to-configuration as well to use single
+		# sudo session and remove one prompt.
+		_ssh "$device" \
+			sudo sh -c \
+				'nix-env --profile /nix/var/nix/profiles/system --set "$store" && /nix/var/nix/profiles/system/bin/switch-to-configuration "$1"' \
+					"$switchop"
+	else
+		warning "The latest system might have been already set."
+	fi
+}
+
+boot() {
+	setenv boot "$1"
+}
+
+switch() {
+	setenv switch "$1"
+}
+
+switch_test() {
+	setenv test "$1"
+}
diff --git a/devices.sh b/devices.sh
index 25632db..3a2dce5 100755
--- a/devices.sh
+++ b/devices.sh
@@ -1,5 +1,5 @@
 #!/usr/bin/env bash
-set -eu
+source "${0%/*}/common.sh"
 declare -a devices
 ################################################################################
 ## aarch64
@@ -24,134 +24,18 @@ valid_device() {
 	return 1
 }
 
-device_system() {
-	nix eval --raw ".#nixosConfigurations.$1.config.nixpkgs.system"
-}
-
-sshdev() {
-	echo "$1" | awk -F- 'NF > 1 { print $2"."$1; exit } { print $1 }'
-}
-
-
-build() {
-	local system="$1"
-	echo "Building $system"
-	local -a args
-	local toplevel=".config.system.build.toplevel"
-	args+=("--keep-going")
-	if [ "$(device_system "$1")" = "armv7l-linux" ]; then
-		toplevel=".config.system.build.cross.x86_64-linux${toplevel}"
-	fi
-	nix build \
-		-o "result-${system}" \
-		"${args[@]}" \
-		"${0%/*}#nixosConfigurations.${system}${toplevel}"
-}
-
-build_validate() {
-	local system="$1"
-	[ -L "result-$system" ] && [ -e "result-$system" ]
-}
-
-copy() {
-	local system="$1"
-	if ! build_validate "$system"; then
-		echo "System '$system' seems to be not build." >&2
-		return 1
-	fi
-	local store="$(readlink -f "result-$system")"
-	local host="$(sshdev "$system")"
-
-	local freespace="$(ssh "$host" -- df -B 1 /nix | awk 'NR == 2 { print $4 }')"
-	local required="$(nix path-info -S "$store" | awk '{ print $2 }')"
-	echo "Free space on device: $(numfmt --to=iec "$freespace")"
-	echo "Required space: $(numfmt --to=iec "$required")"
-	if [ "$required" -ge "$freespace" ]; then
-		echo "There is not enough space to copy clousure to: $system" >&2
-		return 1
-	fi
-
-	echo "Copy closure to: $system"
-	nix copy -s --to "ssh://$host" "$store"
-}
-
-setenv() {
-	local system="$1"
-	if ! build_validate "$system"; then
-		echo "System '$system' seems to be not build." >&2
-		return 1
-	fi
-	local store="$(readlink -f "result-$system")"
-	local host="$(sshdev "$system")"
-
-	echo "Update system: $system"
-	if [ "$(ssh "$host" -- readlink -f /nix/var/nix/profiles/system)" != "$store" ]; then
-		ssh -t "$host" -- \
-			sudo nix-env --profile /nix/var/nix/profiles/system --set "$store"
-	fi
-}
-
-boot() {
-	local system="$1"
-	setenv "$system" || return 1
-
-	local store="$(readlink -f "result-$system")"
-	local host="$(sshdev "$system")"
-
-	echo "Setting boot system: $system"
-	ssh -t "$host" -- \
-		sudo /nix/var/nix/profiles/system/bin/switch-to-configuration boot
-}
-
-is_current() {
-	ssh "$1" -- \
-		'[ "$(readlink -f /run/current-system)" != "$(readlink -f /nix/var/nix/profiles/system)" ]'
-}
-
-switch() {
-	local system="$1"
-	setenv "$system" || return 1
-
-	local store="$(readlink -f "result-$system")"
-	local host="$(sshdev "$system")"
-
-	if is_current "$host"; then
-		echo "Switching: $system"
-		ssh -t "$host" -- \
-			sudo /nix/var/nix/profiles/system/bin/switch-to-configuration switch
-	else
-		echo "This system is already running: $system"
-	fi
-}
-
-switch_test() {
-	local system="$1"
-	setenv "$system" || return 1
-
-	local store="$(readlink -f "result-$system")"
-	local host="$(sshdev "$system")"
-
-	if is_current "$host"; then
-		echo "Testing: $system"
-		ssh -t "$host" -- \
-			sudo /nix/var/nix/profiles/system/bin/switch-to-configuration test
-	else
-		echo "This system is already running: $system"
-	fi
-}
-
 for_devices() {
 	for device in "${selected_devices[@]}"; do
 		for op in "$@"; do
 			if ! "$op" "$device"; then
-				echo "Operation '$op' failed for: $device" >&2
+				error "Operation '$op' failed for: $device" >&2
 				break
 			fi
 		done
 	done
 }
 
-
+################################################################################
 operation="${1:-}"
 [ $# -gt 0 ] && shift
 
@@ -159,7 +43,7 @@ declare -a selected_devices
 if [ $# -gt 0 ]; then
 	for device in "$@"; do
 		if ! valid_device "$device"; then
-			echo "No such device: $device" >&2
+			error "No such device: $device" >&2
 			exit 2
 		fi
 		selected_devices+=("$device")
@@ -168,6 +52,7 @@ else
 	selected_devices=("${devices[@]}")
 fi
 
+
 case "$operation" in
 	help|h)
 		cat <<-EOF
diff --git a/local.sh b/local.sh
new file mode 100755
index 0000000..37985c3
--- /dev/null
+++ b/local.sh
@@ -0,0 +1,58 @@
+#!/usr/bin/env bash
+source "${0%/*}/common.sh"
+
+operations() {
+	for op in "$@"; do
+		if ! "$op" "$(hostname)"; then
+			error "Operation '$op' failed" >&2
+			break
+		fi
+	done
+}
+
+################################################################################
+operation="${1:-}"
+if [ $# -gt 1 ]; then
+	echo "Invalid argument: $2" >&2
+	exit 2
+fi
+
+case "$operation" in
+	help|h)
+		cat <<-EOF
+		Usage $0 operation [device]...
+		Local system builder and updater for remote devices.
+
+		Operations:
+		  build: build device system
+		  boot: set built system to be boot default on the device
+		  switch: switch to the built system on the target device
+		  test: test the built system on the target device
+		EOF
+		;;
+	build|b)
+		operations build
+		;;
+	boot)
+		operations boot
+		;;
+	switch|s)
+		operations switch
+		;;
+	test|t)
+		operations switch_test
+		;;
+	build-switch|bs|"")
+		operations build switch
+		;;
+	build-test|bt)
+		operations build switch_test
+		;;
+	build-boot|bb)
+		operations build boot
+		;;
+	default)
+		echo "Unknown operation: $operation" >&2
+		exit 2
+		;;
+esac