Query AWS RDS free storage

get-rds-free-storage.sh

usage()
{
    echo "usage: get-rds-free-storage.sh -i instance -r region"
}

REGION="ap-southeast-1"
START="$(date -v '-5M' -u '+%Y-%m-%dT%H:%M:%SZ')" # 5 minutes ago
END="$(date -u '+%Y-%m-%dT%H:%M:%SZ')"
INSTANCE_NAME="mydb"

while [ "$1" != "" ]; do
    case $1 in
        -r | --region )         shift
                                REGION=$1
                                ;;
        -i | --instance )       shift
                                INSTANCE_NAME=$1
                                ;;
        -h | --help )           usage
                                exit
                                ;;
        * )                     usage
                                exit 1
    esac
    shift
done


AWS_DEFAULT_REGION="$REGION" aws cloudwatch get-metric-statistics \
  --namespace AWS/RDS --metric-name FreeStorageSpace \
  --start-time $START --end-time $END --period 300 \
  --statistics Average  \
  --dimensions "Name=DBInstanceIdentifier, Value=${INSTANCE_NAME}"