#!/bin/sh

# The dir containing vserver configuration
VSERVERS_CONF=/etc/vservers
# The vserver to use as a template
TEMPLATE=template
# A file containing files (or masks) to not copy from the template vserver.
EXCLUDE_FILE="$VSERVERS_CONF/clone-exclude"
# The ip range to use for creating a new vserver. A number between 2 and 253
# will be appended to this, until an address is found that is not used by
# another vserver..
IP_RANGE=10.42.0.
# The interface on which to create the vserver
INTERFACE=dummy0
# The netmask for the address
NETMASK=24
# The DNS vserver gets a new entry in its /etc/hosts
DNS_VSERVER=dns

function usage()
{
	echo "Usage: $0 name"
	echo "Creates a new vserver with the specified name, which is a clone"
	echo "from the vserver \`\`$TEMPLATE'' with some post-processing done."
}

function find_ip()
{
	IP_FILES="$VSERVERS_CONF/*/interfaces/*/ip"
	for i in {2..53}; do
		IP=${IP_RANGE}$i
		if ! grep ^$IP$ $IP_FILES &>/dev/null; then
			return 0
		fi
	done
	return 1
}

if [ "`id -u`" -eq 0 ]; then
	echo "$0 should not be run as root, it will use sudo where appropriate"
	exit 1
fi

# Check arguments
if [ ! "$#" -eq 1 ]; then
	usage
	exit 1
fi

NAME=$1

if ! echo $NAME | grep "^[a-zA-Z0-9-]*$" &>/dev/null; then
	echo "Name can only contain alphanumerics and dashes"
	exit 1
fi

HOST="$NAME.`hostname --fqdn`"

# Set the IP var
if ! find_ip; then
	echo "No available ip address found, aborting"
	exit 1
fi;

echo "Creating vserver $NAME with address $IP..."
sudo vserver $NAME build -m clone --hostname $HOST --interface $INTERFACE:$IP/$NETMASK -- --source $TEMPLATE --exclude-from $EXCLUDE_FILE

echo "Vserver created, configuring..."
sudo vserver $NAME start
# Regen ssh keys
sudo vserver $NAME exec dpkg-reconfigure openssh-server
# Setup git - Add a branch for this vserver
sudo vserver $NAME exec git branch $NAME origin/$TEMPLATE
sudo vserver $NAME exec git checkout $NAME
# Remove the template branch, to prevent pushing it back later on 
sudo vserver $NAME exec git branch -d $TEMPLATE
# Push our new branch upstream so it can be pushed with "git push" afterwards.
sudo vserver $NAME exec git push origin $NAME:$NAME
# Enable vhashify/vunify
sudo mkdir $VSERVER_CONF/$NAME/apps/vunify
sudo touch $VSERVER_CONF/$NAME/apps/vunify/dummy # For git

# Remove trailing slashes from the confdir. git only works when we're using
# relative paths and the cwd is / for some reason...
CONF_FOR_GIT=`echo $VSERVERS_CONF/$NAME | sed "s#^/*##"`
# Commit the configuration
(cd /; git add $CONF_FOR_GIT)
(cd /; git commit $CONF_FOR_GIT --edit --message "vserver: Add $NAME vserver configuration.")

# Add this new vserver to the hosts file in the dns vserver and in the host
for file in /etc/hosts "$VSERVERS_CONF/$DNS_VSERVER/vdir/etc/hosts"; do
	sudo sh -c "echo '$IP	$NAME' >> '$file'"
done

# Restart dnsmasq in the dns vserver
sudo vserver $DNS_VSERVER exec /usr/bin/killall -HUP dnsmasq"