make-debian-mpd-chroot

#!/usr/bin/env bash
## 
## `make-debian-mpd-chroot' is a script to build the latest
## version of mpd for debian inside a temporary debian chroot on a
## non-debian build environment/host, like arch.
##
##  Copyright (C) 2015 Ronald van Engelen <ronalde+github@lacocina.nl>
##  This program is free software: you can redistribute it and/or modify
##  it under the terms of the GNU General Public License as published by
##  the Free Software Foundation, either version 3 of the License, or
##  (at your option) any later version.
##
##  This program is distributed in the hope that it will be useful,
##  but WITHOUT ANY WARRANTY; without even the implied warranty of
##  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
##  GNU General Public License for more details.
##
##  You should have received a copy of the GNU General Public License
##  along with this program.  If not, see <http://www.gnu.org/licenses/>.
##
## The main and helper scripts and documentation are published at 
## https://github.com/ronalde/build-latest-mpd-for-debian
## 
## Apart from a fairly recent versions of debootstrap, systemd and
## wget or curl, no additional packages are required for the build
## environment. When you use debian or ubuntu as your build
## enviroment, you should have a look at git-buildpackage.
##
## Also see `README'

LANG=C

appname="build-latest-mpd-for-debian"
DEBCHROOT_MIRROR="${DEBCHROOT_MIRROR:-http://ftp.debian.org/debian}"
## or use local apt cacher like approx
#DEBCHROOT_MIRROR="http://localnet:9999/debian"
DEBCHROOT_VERSION="${DEBCHROOT_VERSION:-jessie}"
DEBCHROOT_ARCH="${DEBCHROOT_ARCH:-amd64}"
debchroot_variant="buildd"
debchroot_additional_packages="devscripts,coreutils,dpkg-dev,apt-utils,openssh-client,libwww-perl"
helper_script_name=build-latest-debian-mpd-package
helper_script_downloadpath=/tmp
helper_script_downloadtarget=${helper_script_downloadpath}/${helper_script_name}
helper_script_path=/usr/local/bin
tempchroot_template="${appname}.${DEBCHROOT_VERSION}.${DEBCHROOT_ARCH}.XXXX"
url="https://raw.githubusercontent.com/ronalde/${appname}/master/${helper_script_name}"

scriptname="$(basename ${0})"

function create_chroot {
    ## download and install a virgin debian chroot
    
    printf "**  performing debootstrap in \`%s' ... " "${debchroot_targetdir}" 2>&1 | tee -a ${logfile}
    res="$(debootstrap \
	--arch=${DEBCHROOT_ARCH} \
	--include="${debchroot_additional_packages}" \
	--variant=${debchroot_variant} \
	${DEBCHROOT_VERSION} \
	${debchroot_targetdir} \
	"${DEBCHROOT_MIRROR}" >> ${logfile} 2>&1)" 
    if [[ $? -ne 0 ]]; then
	printf "ERROR:\n%s\n" "${res}" 2>&1 | tee -a ${logfile}
	exit 1
    else
	printf "done.\n" 2>&1 | tee -a ${logfile}
    fi
}

function download_helper_script {
    ## get the latest version of the helper script using wget or curl
    
    wget -q "${url}" -O "${helper_script_downloadtarget}" >> ${logfile} 2>&1 || \
	curl -s -k -o "${helper_script_downloadtarget}" "${url}" >> ${logfile} 2>&1
}

function install_helper_script {
    ## set up sources.list inside the chroot, install the helper
    ## script, add it to root's profile and set autologon

    printf "downloading helper script from repository ..." 2>&1 | tee -a ${logfile}
    res=$(download_helper_script)
    if [[ $? -ne 0 ]]; then
	printf "\nerror: could not download the the helper script from \n%s\n" \
	       "${url}" 2>&1 | tee -a ${logfile}
	exit 1
    else  
	printf "done.\n" 2>&1 | tee -a ${logfile}

	printf "*** populate sources.list inside the chroot ... " 2>&1 | tee -a ${logfile}
	debchroot_sourceslist="${debchroot_targetdir}/etc/apt/sources.list"
	printf "deb %s %s main\n" \
	       "${DEBCHROOT_MIRROR}" "${DEBCHROOT_VERSION}" > ${debchroot_sourceslist}
	printf "deb-src %s %s main\n" \
	       "${DEBCHROOT_MIRROR}" "${DEBCHROOT_VERSION}" >> ${debchroot_sourceslist}
	printf "done.\n" 2>&1 | tee -a ${logfile}
	
	printf "**  installing the mpd builder script \`%s' inside the chroot ... " \
	       "${helper_script_name}" 2>&1 | tee -a ${logfile}
	
	res=$(install --mode=0555 "${helper_script_downloadtarget}" "${debchroot_targetdir}${helper_script_path}"  >> ${logfile} 2>&1)
	if [[ $? -ne 0 ]]; then
	    printf "ERROR:\n%s\n" "${res}" 2>&1 | tee -a ${logfile}
	    exit 1
	else
	    printf "done.\n" 2>&1 | tee -a ${logfile}
	fi
	dotprofile="${debchroot_targetdir}/root/.profile"
	printf "**  insert the script in to \`%s' ... " "${dotprofile}" 2>&1 | tee -a ${logfile}
	echo "${helper_script_path}/${helper_script_name}" > ${dotprofile}
	printf "done.\n" 2>&1 | tee -a ${logfile}
	
	printf "**  setting autologin for root inside chroot ... " 2>&1 | tee -a ${logfile}
	console_getty=${debchroot_targetdir}/lib/systemd/system/console-getty.service
	sed -i 's#^ExecStart.*#ExecStart=-/sbin/agetty --autologin root --noclear --keep-baud console 115200,38400,9600 $TERM#' "${console_getty}"
	printf "done.\n" 2>&1 | tee -a ${logfile}
    fi
    
}

function spawn_chroot {
    ## boot the chroot using systemd-nspawn and wait for it to execute
    ## the helper script and finally halt, after which try to copy the
    ## created mpd package from the chroot to the current directory.
    
    printf "**  spawning the chroot.\n" 2>&1 | tee -a ${logfile} 
    ## boot the chroot
    systemd-nspawn -bD "${debchroot_targetdir}" 2>&1 | tee -a ${logfile}
    printf "**  done spawning.\n" 2>&1 | tee -a ${logfile}
    ## get the created mpd package
    package_path="$(find "${debchroot_targetdir}/root" -name 'mpd_*.deb')"
    if [[ $? -ne 0 ]]; then
	printf "error: could not find a package in \`%s'.\n" "${package_path}" 2>&1 | tee -a ${logfile}
    else
	package_name="$(basename "${package_path}")"
	res=$(cp ${package_path} ./2>&1 | tee -a ${logfile})
	if [[ $? -ne 0 ]]; then
	    printf "error: could not copy package from \`%s'.\n" 2>&1 | tee -a ${logfile}
	    printf "inspect the chroot by running: \`%s'\n" \
		   "systemd-nspawn -bD "${debchroot_targetdir}"" 2>&1 | tee -a ${logfile}
	else
	    printf "**  all done; the resulting package is copied locally to:\n%s\n\n" \
		   "./${package_name}"  2>&1 | tee -a ${logfile}
	    printf "(you may delete the chroot \`%s')\n" \
		   "./${debchroot_targetdir}" 2>&1 | tee -a ${logfile}
	fi
    fi
       
}

## main

if [[ "${BASH_SOURCE[0]}" != "${0}" ]]; then
    ## we're being sourced (for testing purposes); do nothing
    debchroot_targetdir="$1"
    if [[ -z "${debchroot_targetdir}" ]]; then
	printf "sourcing is only useful when you specify an existing chroot.\n"
    else
	printf "script \`%s' is being sourced\n" "${BASH_SOURCE[0]}"
	if [[ ! -d "${debchroot_targetdir}" ]]; then
	    printf "warning: specified debchroot_targetdir \`%s' does not exist.\n" "${debchroot_targetdir}"
	else
	    printf "using exisiting debchroot_targetdir \`%s'\n" "${debchroot_targetdir}"
	    install_helper_script
	fi
    fi
else
    ## we're being run
    logfile=$(mktemp --tmpdir "${scriptname}.XXXX")

    ## start logging
    printf "starting %s at %s\n" "${scriptname}" "$(date)" 2>&1 | tee ${logfile} 
    printf "**  logging to \`%s'.\n" "${logfile}" 2>&1 | tee -a ${logfile} 
    printf "**  creating a new temporary debchroot_targetdir.\n" 2>&1 | tee -a ${logfile} 
    debchroot_targetdir="$(mktemp -d ${tempchroot_template})"
    if [[ $? -ne 0 ]]; then
	printf "ERROR:\n%s\n" "${debchroot_targetdir}" 2>&1 | tee -a ${logfile}
    else
	printf "**  debchroot_targetdir is \`%s'.\n" "${debchroot_targetdir}" 2>&1 | tee -a ${logfile}
	create_chroot && \
	    install_helper_script && \
	    spawn_chroot
    fi
fi