opam-deploy

#! /bin/bash
set -e

if [ -r /etc/opam-deploy.conf ]; then
    . /etc/opam-deploy.conf
fi

rsync_options="-rlptD --delete"
backlog=3

run() { echo "+ $*"; "$@"; }

confirm()
{
    while true; do
	echo -n "$*"
	read ans
	case "$ans" in
	    y|yes) return;;
	    n|no) exit;;
	esac
    done
}

if [ -z "$BUILD_HOST" ]; then
    echo "BUILD_HOST must be set in /etc/opam-deploy.conf."
fi
if [ $# -eq 0 ]; then
    if [ -z "$OPAMSWITCH" ]; then
	echo "Set OPAMSWITCH in /etc/opam-deploy.conf or pass it as an argument."
	exit 64
    fi
    switch="$OPAMSWITCH"
elif [ $# -eq 1 ]; then
    switch="$1"
else
    echo "Usage: $0 [SWITCH]"
    exit 64
fi
next="/opt/opam/${switch}-next"

[ -e /opt/opam ] || run install -d -m 755 /opt/opam

if [ ! -e "${next}" -a -e "/opt/opam/${switch}" ]; then
    run cp -al "/opt/opam/${switch}" "${next}"
fi
run rsync $rsync_options "rsync://${BUILD_HOST}/opam/${switch}/" "${next}/"

confirm "Activate ${next}? "
i=`expr $backlog + 1`
if [ -e "/opt/opam/${switch}.prev-$i" ]; then
    run rm -rf "/opt/opam/${switch}.prev-$i"
fi
for i in `seq $backlog -1 1`; do
    if [ -e "/opt/opam/${switch}.prev-$i" ]; then
	run mv "/opt/opam/${switch}.prev-$i" "/opt/opam/${switch}.prev-`expr $i + 1`"
    fi
done
if [ -e "/opt/opam/${switch}" ]; then
    run mv "/opt/opam/${switch}" "/opt/opam/${switch}.prev-1"
fi
run mv "${next}" "/opt/opam/${switch}"