aws ec2 change route table lsb script

ec2-route

#!/bin/sh
#
# chkconfig: 12345 01 99
# description: EC2 route change

. /etc/rc.d/init.d/functions

prog=${0##*/}
lock=/var/lock/subsys/$prog

instance_id=`curl -s http://169.254.169.254/latest/meta-data/instance-id`
az=`curl -s http://169.254.169.254/latest/meta-data/placement/availability-zone`
region=${az%[a-z]}

# route_table_id=rtb-xxxxxxxx
# destination_cidr_block=192.168.0.128/32

[ -f /etc/sysconfig/$prog ] && . /etc/sysconfig/$prog

[ -z "$route_table_id" ] && exit 0
[ -z "$destination_cidr_block" ] && exit 0

function has_route
{
  cnt=`aws ec2 describe-route-tables --output text --region "$region" --filters \
    Name=route-table-id,Values="$route_table_id" \
    Name=route.destination-cidr-block,Values="$destination_cidr_block" \
      | wc -l`

  if [ "$cnt" -gt 0 ]; then
    return 0
  else
    return 1
  fi
}

function has_my_route
{
  cnt=`aws ec2 describe-route-tables --output text --region "$region" --filters \
    Name=route-table-id,Values="$route_table_id" \
    Name=route.destination-cidr-block,Values="$destination_cidr_block" \
    Name=route.instance-id,Values="$instance_id" \
      | wc -l`

  if [ "$cnt" -gt 0 ]; then
    return 0
  else
    return 1
  fi
}

function create_route
{
  echo -n "create route ..."

  aws ec2 create-route --output text \
    --region "$region" \
    --route-table-id "$route_table_id" \
    --instance-id "$instance_id" \
    --destination-cidr-block "$destination_cidr_block" \
      2>&1 | logger -s -i -t "$prog" 2>&1

  ret=${PIPESTATUS[0]}
  [ "$ret" -eq 0 ] && success || failure
  echo
  return "$ret"
}

function delete_route
{
  echo -n "delete route ..."

  aws ec2 delete-route --output text \
    --region "$region" \
    --route-table-id "$route_table_id" \
    --destination-cidr-block "$destination_cidr_block" \
      2>&1 | logger -s -i -t "$prog" 2>&1

  ret=${PIPESTATUS[0]}
  [ "$ret" -eq 0 ] && success || failure
  echo
  return "$ret"
}

function start
{
  has_my_route && return 0
  has_route && delete_route
  create_route
}

function stop
{
  ! has_my_route && return 0
  delete_route
}

function status()
{
  if has_my_route; then
    echo ok
    return 0
  else
    echo ng
    return 3
  fi
}

case "$1" in
  start)
    start
    ;;
  stop)
    stop
    ;;
  status)
    status
    ;;
  *)
    echo "Usage: ec2-route {start|stop|status}"
    exit 2
esac

exit $?