#!/bin/bash

# Copyright (C) 2016 Red Hat, Inc.

#

# 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/>.

set -euo pipefail

IFS=$'\n\t'

# This is a small wrapper script that automatically fetches

# the storage options from the docker-storage sysconfig file

# and passes them to the migrator.

#

# The script supports both in-container runs and direct

# invocation.

MIGRATOR=/usr/bin/v1.10-migrator-local

STORAGE_FILE=/etc/sysconfig/docker-storage

GRAPH=/var/lib/docker

main() {

	# are we in a container?

	if [[ -n ${container-} ]]; then

		if [[ ! -d /host ]]; then

			echo "ERROR: Running inside a container, but /host not mounted." >&2

			exit 1

		fi

		cp "$MIGRATOR" /host/tmp

		MIGRATOR="chroot /host /tmp/$(basename $MIGRATOR)"

		STORAGE_FILE=/host${STORAGE_FILE}

	fi

	if [ ! -d "$GRAPH" ]; then

		echo "ERROR: Cannot find docker root dir at \"$GRAPH\"." >&2

		exit 1

	fi

	# load storage opts if we can find the file

	local storage_opts=

	if [ -r "$STORAGE_FILE" ] && grep -q -E '^DOCKER_STORAGE_OPTIONS\s*=' "$STORAGE_FILE"; then

		storage_opts=$(sed -n -e 's/^DOCKER_STORAGE_OPTIONS\s*=\s*// p' "$STORAGE_FILE")

		storage_opts=${storage_opts#\"}

		storage_opts=${storage_opts%\"}

	fi

	CMD="$MIGRATOR --graph $GRAPH $storage_opts"

	echo "RUNNING: $CMD"

	eval $CMD

}

main "$@"