wait_for_rds_instance.sh

#!/bin/bash
# This script takes two arguments: rds database identifier and timeout.

DB_ID=$1
TIMEOUT=$2
POLL_INTERVAL=60
OK_STATES=("backing-up" "available" "modifying" "resetting-master-credentials")

seconds_left=$TIMEOUT

while [[ "${seconds_left}" -gt 0 ]]
do
  db_status=$(aws rds describe-db-instances --db-instance-identifier $DB_ID --query 'DBInstances[0].[DBInstanceStatus]' --output text)
  if [[ "${OK_STATES[@]} " =~ "${db_status}" ]]; then
    sleep 120
    exit 0
  else
    seconds_left="$((${seconds_left} - ${POLL_INTERVAL}))"
    sleep ${POLL_INTERVAL}
  fi
done

# Time exceeded here
exit 1