list-rds-by-tag.py

#!/usr/bin/env python

import boto3

rds = boto3.client('rds', region_name='ap-south-1')
dbs = rds.describe_db_instances()

def get_tags_for_db(db):
    instance_arn = db['DBInstanceArn']
    instance_tags = rds.list_tags_for_resource(ResourceName=instance_arn)
    return instance_tags['TagList']

for db in dbs['DBInstances']:
    db_tags = get_tags_for_db(db)

    for tag in db_tags:
        if tag['Key'] == 'Business_Vertical' and (tag['Value']).lower() == 'ds':
            print(db["DBInstanceIdentifier"], ",", db["DBInstanceClass"])