wrapacker

#!/usr/bin/env bash

#
# wrapacker - https://github.com/elasticdog/packer-arch
#
# A script to automatically ensure the latest ISO download URL and optionally
# use a mirror from the provided country in order to build an Arch Linux box
# using Packer.
#
# Copyright (c) 2015 Aaron Bull Schaefer <aaron@elasticdog.com>
# This source code is provided under the terms of the ICS License
# that can be be found in the LICENSE file.
#

##### Constants

# country codes supported by https://www.archlinux.org/mirrorlist/
VALID_COUNTRIES=(AT AU BD BE BG BR BY CA CH CL CN CO CZ DE DK EC ES FR GB GR HR HU ID IE IL IN IR IS IT JP KR KZ LT LU LV MK NC NL NO NZ PH PL PT RO RS RU SE SG SK TR TW UA US VN ZA)


##### Functions

# print a message to stderr
warn() {
	local fmt="$1"
	shift
	printf "wrapacker: $fmt\n" "$@" >&2
}

# print a message to stderr and exit with either
# the given status or that of the most recent command
die() {
	local st="$?"
	if [[ "$1" != *[^0-9]* ]]; then
		st="$1"
		shift
	fi
	warn "$@"
	exit "$st"
}

# test the VALID_COUNTRIES array for membership of the given value
validate_country() {
	local haystack="VALID_COUNTRIES[@]"
	local needle=$1
	local found=1
	for element in "${!haystack}"; do
		if [[ $element == $needle ]]; then
			found=0
			break
		fi
	done
	return $found
}

# print this script's usage message to stderr
usage() {
	cat <<-EOF >&2
	usage: wrapacker [-c COUNTRY] [-p PROVIDER] [-h]
	EOF
}

# print the list of valid countries to stderr
print_valid_countries() {
	printf '\n*** VALID COUNTRY CODES ***\n\n' >&2
	for country in "${VALID_COUNTRIES[@]}"; do
		printf '%-6s\n' "$country"
	done | column >&2
}

# print the list of valid providers to stderr
print_valid_providers() {
	printf '\n*** VALID PROVIDERS ***\n\n' >&2
	for provider in {parallels,virtualbox,vmware}; do
		printf '%-6s\n' "$provider"
	done | column >&2
}

# print this script's help message to stdout
help() {
	cat <<-EOF

	NAME
	     wrapacker -- wrap packer to build arch with custom mirror settings

	SYNOPSIS
	     wrapacker [options...]

	DESCRIPTION

	     wrapacker will automatically ensure the latest ISO download URL and
	     will optionally use a mirror from the provided country in order to
	     build an Arch Linux box using Packer.

	OPTIONS
	     -c, --country=COUNTRY
	            the country code to download from;
	            defaults to the kernel.org US mirror

	     -p, --provider=PROVIDER
	            the packer provider to build with;
	            defaults to virtualbox

	     -d, --dry-run
	            do not actually perform the build, just show what would run

	     -h, --help
	            view this help message

	AUTHOR
	     Aaron Bull Schaefer <aaron@elasticdog.com>

	EOF
}


##### Main

# check for dependencies
for cmd in {awk,curl,sed,tr}; do
	command -v $cmd > /dev/null || die "required command \"$cmd\" was not found"
done

# reset all variables that might be set
country=''
provider=''
dry_run=''

# parse command line options
while [[ $1 != '' ]]; do
	case $1 in
		-c | --country)
			country=$(echo "$2" | tr '[:lower:]' '[:upper:]')
			shift
			;;
		--country=*)
			country=$(echo "${1#*=}" | tr '[:lower:]' '[:upper:]')
			;;
		-p | --provider)
			provider=$2
			shift
			;;
		--provider=*)
			provider=${1#*=}
			;;
		-d| --dry-run)
			dry_run=true
			;;
		-h | --help | -\?)
			help
			print_valid_countries
			print_valid_providers
			exit 0
			;;
		--*)
			warn "unknown option -- ${1#--}"
			usage
			exit 1
			;;
		*)
			warn "unknown option -- ${1#-}"
			usage
			exit 1
			;;
	esac
	shift
done

if [[ $provider ]]; then
	case $(echo "$provider" | tr '[:upper:]' '[:lower:]') in
		parallels | parallels-iso)
			PACKER_PROVIDER='parallels-iso'
			;;
		virtualbox | virtualbox-iso)
			PACKER_PROVIDER='virtualbox-iso'
			;;
		vmware | vmware-iso)
			PACKER_PROVIDER='vmware-iso'
			;;
		*)
			warn "unknown provider -- ${provider}"
			usage
			print_valid_providers
			exit 1
			;;
	esac
else
	PACKER_PROVIDER='virtualbox-iso'
fi

if [[ $country ]]; then
	if validate_country "$country"; then
		MIRRORLIST="https://www.archlinux.org/mirrorlist/?country=${country}&protocol=http&protocol=https&ip_version=4&use_mirror_status=on"
		MIRROR=$(curl -s "$MIRRORLIST" | awk '/#Server/{ print $3; exit }' | sed 's|/$repo.*||')
	else
		warn 'INVALID COUNTRY SPECIFIED - %s' "$country"
		usage
		print_valid_countries
		exit 1
	fi
else
	MIRROR='https://mirrors.kernel.org/archlinux'
fi

SHA1SUMS=$(curl -s "${MIRROR}/iso/latest/sha1sums.txt")
ISO_NAME=$(echo "$SHA1SUMS" | awk '/dual.iso/{ print $2 }')

ISO_URL="${MIRROR}/iso/latest/${ISO_NAME}"
ISO_CHECKSUM=$(echo "$SHA1SUMS" | awk '/dual.iso/{ print $1 }')

if [[ $dry_run ]]; then
	cat <<-EOF
		packer build \\
			-only=$PACKER_PROVIDER \\
			-var "iso_url=$ISO_URL" \\
			-var "iso_checksum=$ISO_CHECKSUM" \\
			arch-template.json
	EOF
else
	packer build \
		-only=$PACKER_PROVIDER \
		-var "iso_url=$ISO_URL" \
		-var "iso_checksum=$ISO_CHECKSUM" \
		arch-template.json
fi

exit $?