boto3 based script to find ELB (AWS Load balancers) without targets (very näive, use with cautios)

elb-with-no-targets.py

import boto3

LB_TO_TARGET_ARN = {}

def main():
    client = boto3.client('elbv2')  
    load_balancers = client.describe_load_balancers()
    for lb in load_balancers['LoadBalancers']:
      lb_arn = lb['LoadBalancerArn']
      attr_for_lb = client.describe_listeners(LoadBalancerArn=lb_arn)
      tg_arn = attr_for_lb['Listeners'][0]['DefaultActions'][0]['TargetGroupArn']
      lb_name = lb['LoadBalancerName']
      LB_TO_TARGET_ARN[lb_arn] = {'tg_arn': tg_arn, 'lb_name': lb_name}

    for item in LB_TO_TARGET_ARN:
      tg_arn = LB_TO_TARGET_ARN[item]['tg_arn']
      lb_name = LB_TO_TARGET_ARN[item]['lb_name']
      tg_instances = client.describe_target_health(TargetGroupArn=tg_arn)
      count_targets = len(tg_instances['TargetHealthDescriptions'])
      if count_targets == 0:
        print(f"Load balancer with no targets for {lb_name}")
      else:
        pass
        #print(f"Total of {count_targets} for {lb_name}")

main()