gitolite-backup.sh

#!/bin/sh

# gitolite-backup.sh
#
# Copyright (C) 2012 YouView TV Ltd. <william.manley@youview.com>
#
# 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 2 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, write to the Free Software
# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

gitolite_login=$1

if [ -z "$gitolite_login" ];
then
	echo -e "Usage\n\t$0 [gitolite-ssh-login]" >&2
	exit 1
fi

list_repos() {
	ssh "$1" info 2>/dev/null | grep -P '\t' | cut -f2
}

create_repo() {
	mkdir -p "repos/$2" &&
	cd "repos/$2" &&
	git init --bare &&
	git remote add origin "$1:$2"
}

update_repo() {
	cd "repos/$repo" &&
	git fetch origin --prune &&
	git gc --auto
}

backup_repo() {
	cd "repos/$repo" &&
	git for-each-ref refs/remotes/origin --format='%(refname)' | while read ref
	do
		refname="${ref##refs/remotes/origin/}"
		echo git update-ref "refs/backup/$3/$refname" "$ref"
		git update-ref "refs/backup/$3/$refname" "$ref"
	done
	git pack-refs --all
}

# We run this twice to make it closer to a snapshot.  The first one may take
# some time but the second one should be very quick.  Really the way to
# guarantee a snapshot would be to run it in a loop and when we go through two
# iterations pulling down no changes we know it is a true snapshot.
for i in $(seq 2);
do
	list_repos "$gitolite_login" | while read repo
	do
		if [ ! -d "$repo" ]; then
			echo "Found new repo $repo"
			( create_repo "$gitolite_login" "$repo" )
		fi
		( update_repo "$gitolite_login" "$repo" )
	done
done

# TODO: Make the following safe even if we are interuppted by SIGINT, SIGTERM,
# etc.
date=$(date +%F)

if [ "$date" == "$(<last_backup)" ]
then
	echo "Have already done a backup today, exiting"
	exit 1
fi

echo "$date" > last_backup

ls repos/ | while read repo
do
	( backup_repo "$gitolite_login" "$repo" "$date" )
done