#!/bin/bash
#
# Copyright (c) 2011 Citrix Systems, Inc.
# Copyright 2011 OpenStack Foundation
# All Rights Reserved.
#
#    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.
#

set -eux

BRIDGE=
NAME_LABEL=
TEMPLATE_NAME=

usage()
{
cat << EOF

  Usage: $0 -t TEMPLATE_NW_INSTALL -l NAME_LABEL [-n BRIDGE]

  Install a VM from a template

  OPTIONS:

     -h           Shows this message.
     -t template  VM template to use
     -l name      Specifies the name label for the VM.
     -n bridge    The bridge/network to use for eth0. Defaults to xenbr0
EOF
}

get_params()
{
    while getopts "hbn:r:l:t:" OPTION; do
        case $OPTION in
            h) usage
                exit 1
                ;;
            n)
                BRIDGE=$OPTARG
                ;;
            l)
                NAME_LABEL=$OPTARG
                ;;
            t)
                TEMPLATE_NAME=$OPTARG
                ;;
            ?)
                usage
                exit
                ;;
        esac
    done
    if [[ -z $BRIDGE ]]; then
        BRIDGE=xenbr0
    fi

    if [[ -z $TEMPLATE_NAME ]]; then
        echo "Please specify a template name" >&2
        exit 1
    fi

    if [[ -z $NAME_LABEL ]]; then
        echo "Please specify a name-label for the new VM" >&2
        exit 1
    fi
}


xe_min()
{
    local cmd="$1"
    shift
    xe "$cmd" --minimal "$@"
}


find_network()
{
    result=$(xe_min network-list bridge="$1")
    if [ "$result" = "" ]; then
        result=$(xe_min network-list name-label="$1")
    fi
    echo "$result"
}


create_vif()
{
    local v="$1"
    echo "Installing VM interface on [$BRIDGE]"
    local out_network_uuid
    out_network_uuid=$(find_network "$BRIDGE")
    xe vif-create vm-uuid="$v" network-uuid="$out_network_uuid" device="0"
}


# Make the VM auto-start on server boot.
set_auto_start()
{
    local v="$1"
    xe vm-param-set uuid="$v" other-config:auto_poweron=true
}


destroy_vifs()
{
    local v="$1"
    IFS=,
    for vif in $(xe_min vif-list vm-uuid="$v"); do
        xe vif-destroy uuid="$vif"
    done
    unset IFS
}


get_params "$@"

vm_uuid=$(xe_min vm-install template="$TEMPLATE_NAME" new-name-label="$NAME_LABEL")
destroy_vifs "$vm_uuid"
set_auto_start "$vm_uuid"
create_vif "$vm_uuid"
xe vm-param-set actions-after-reboot=Destroy uuid="$vm_uuid"