#!/bin/bash

# This is a simple mirroring script. To save bandwidth it first checks a
# timestamp via HTTP and only runs rsync when the timestamp differs from the
# local copy. As of 2016, a single rsync run without changes transfers roughly
# 6MiB of data which adds up to roughly 250GiB of traffic per month when rsync
# is run every minute. Performing a simple check via HTTP first can thus save a
# lot of traffic.

home="/srv"
target="${home}/repo/archlinux"
tmp="${home}/tmp"
lock='/tmp/mirrorsync.lck'
# NOTE: You'll probably want to change this or remove the --bwlimit setting in
# the rsync call below
bwlimit=4096
# NOTE: most people reading this very likely need to change this since
# rsync.archlinux.org requires you to be a tier 1 mirror
source='rsync://pkg.adfinis.com/archlinux/'
lastupdate_url="https://pkg.adfinis.com/archlinux//lastupdate"
#source='rsync://mirror.hb9hil.org/archlinux/'                                  
#lastupdate_url="https://mirror.hb9hil.org/archlinux/lastupdate"

[ ! -d "${target}" ] && mkdir -p "${target}"
[ ! -d "${tmp}" ] && mkdir -p "${tmp}"

exec 9>"${lock}"
flock -n 9 || exit

# if we are called without a tty (cronjob) only run when there are changes
if ! tty -s && diff -b <(curl -s "$lastupdate_url") "$target/lastupdate" >/dev/null; then
	exit 0
fi

if ! stty &>/dev/null; then
    QUIET="-q"
fi

rsync -rtlvH --safe-links --delete-after --progress -h ${QUIET} --timeout=600 --contimeout=60 -p \
	--delay-updates --no-motd \
	--temp-dir="${tmp}" \
	--exclude='*.links.tar.gz*' \
	--exclude='/other' \
	--exclude='/sources' \
	${source} \
	"${target}"
