#!/bin/bash

# -------------------------------------------------------------------------- #
# Copyright 2002-2017, OpenNebula Project, OpenNebula Systems                #
#                                                                            #
# Licensed under the Apache License, Version 2.0 (the "License"); you may    #
# not use this file except in compliance with the License. You may obtain    #
# a copy of the License at                                                   #
#                                                                            #
# http://www.apache.org/licenses/LICENSE-2.0                                 #
#                                                                            #  
# Unless required by applicable law or agreed to in writing, software        #
# distributed under the License is distributed on an "AS IS" BASIS,          #
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.   #
# See the License for the specific language governing permissions and        #
# limitations under the License.                                             #
#--------------------------------------------------------------------------- #
# snap_create host:parent_image snap_id vmid ds_id

SRC=$1
SNAP_ID=$2
VMID=$3
DSID=$4

if [ -z "${ONE_LOCATION}" ]; then
    TMCOMMON=/var/lib/one/remotes/tm/tm_common.sh
    DATASTORES=/var/lib/one/datastores
else
    TMCOMMON=$ONE_LOCATION/var/remotes/tm/tm_common.sh
    DATASTORES=$ONE_LOCATION/var/datastores
fi

DRIVER_PATH=$(dirname $0)

source $TMCOMMON
source ${DRIVER_PATH}/../../vmm/kvm/kvmrc

SRC_PATH=$(arg_path $SRC)
SRC_HOST=$(arg_host $SRC)

DS_SYS_ID=$(echo $SRC_PATH | $AWK -F '/' '{print $(NF-2)}')
#-------------------------------------------------------------------------------
# Get Image information
#-------------------------------------------------------------------------------

DISK_ID=$(basename ${SRC} | cut -d. -f2)

XPATH="${DRIVER_PATH}/../../datastore/xpath.rb --stdin"

unset i j XPATH_ELEMENTS

while IFS= read -r -d '' element; do
    XPATH_ELEMENTS[i++]="$element"
done < <(onevm show -x $VMID| $XPATH \
                    /VM/TEMPLATE/DISK[DISK_ID=$DISK_ID]/SIZE \
                    /VM/TEMPLATE/DISK[DISK_ID=$DISK_ID]/SOURCE \
                    /VM/TEMPLATE/DISK[DISK_ID=$DISK_ID]/CLONE \
                    /VM/TEMPLATE/DISK[DISK_ID=$DISK_ID]/TARGET \
                    /VM/DEPLOY_ID \
                    '%m%/VM/TEMPLATE/DISK/TARGET')

SIZE="${XPATH_ELEMENTS[j++]}"
DISK_SRC="${XPATH_ELEMENTS[j++]}"
CLONE="${XPATH_ELEMENTS[j++]}"
TARGET="${XPATH_ELEMENTS[j++]}"
DEPLOY_ID="${XPATH_ELEMENTS[j++]}"
ALL_DISKS="${XPATH_ELEMENTS[j++]}"

SYSTEM_DS_PATH=$(dirname ${SRC_PATH})
SYSTEM_DS_DISK_PATH="${SYSTEM_DS_PATH}/disk.${DISK_ID}"

VG_NAME="vg-one-${DS_SYS_ID}"
ORIG_LV_NAME="lv-one-vm-${VMID}-${DISK_ID}"
NEW_LV_NAME="${ORIG_LV_NAME}-snap${SNAP_ID}"

CMD=$(cat <<EOT
set -ex -o pipefail

hostn=\$(hostname -s)
SNAP_DEV="/dev/${VG_NAME}-\${hostn}/${NEW_LV_NAME}"

DOC="
<domainsnapshot>
  <name>${DISK_ID}-${SNAP_ID}</name>
  <description>snap ${DISK_ID}-${SNAP_ID}</description>
  <disks>"

for disk in $ALL_DISKS; do
    if [ "\$disk" = "$TARGET" ]; then
        DOC="\$DOC
    <disk name='\$disk' snapshot='external'>
      <source file='\$SNAP_DEV'/>
    </disk>"
    else
        DOC="\$DOC
    <disk name='\$disk' snapshot='no'/>"
    fi
done

DOC="\$DOC
  </disks>
</domainsnapshot>"

PREVIOUS_SNAP=\$(readlink $SYSTEM_DS_DISK_PATH)

# Temporary xml file
FILENAME="/tmp/snapshot-$VMID-$DISK_ID-$SNAP_ID"
echo "\$DOC" > \$FILENAME

if virsh -c $LIBVIRT_URI domfsfreeze $DEPLOY_ID ; then
    trap "virsh -c $LIBVIRT_URI domfsthaw $DEPLOY_ID" EXIT TERM INT HUP
elif virsh -c $LIBVIRT_URI suspend $DEPLOY_ID; then
    trap "virsh -c $LIBVIRT_URI resume $DEPLOY_ID" EXIT TERM INT HUP
else
    error_message "Could not domfsfreeze or suspend domain"
    exit 1
fi

$SUDO $LVCREATE -T -V ${SIZE}M -n $NEW_LV_NAME ${VG_NAME}-\${hostn}/onethinpool
$QEMU_IMG create -o backing_fmt=qcow2 -b "\${PREVIOUS_SNAP}" \
    -f qcow2 ${QCOW2_OPTIONS} "\${SNAP_DEV}"

virsh -c $LIBVIRT_URI snapshot-create $DEPLOY_ID --disk-only --atomic --no-metadata \
    --reuse-external --xmlfile \$FILENAME

rm \${FILENAME}

ln -sf \$SNAP_DEV $SYSTEM_DS_DISK_PATH

EOT
)

ssh_exec_and_log "${SRC_HOST}" "${CMD}" \
                 "Error creating snapshot ${SNAP_DEV}"
