AWS Lambda SSM Parameter Store Updater function

AWS Lambda SSM Parameter Store Updater function.py

import boto3, os, json

REGION = os.environ['REGION']
ASG_NAME = os.environ['ASG_NAME']
SSM_PARAMETER_NAME = os.environ['SSM_PARAMETER_NAME']

ssm = boto3.client('ssm', region_name=REGION)
autoscaling = boto3.client('autoscaling', region_name=REGION)

def lambda_handler(event, context):
    # get new instance id
    instance_ids = []
    asg_response = autoscaling.describe_auto_scaling_groups(AutoScalingGroupNames=[ASG_NAME])
    for i in asg_response['AutoScalingGroups']:
     for k in i['Instances']:
        instance_ids.append(k['InstanceId'])
         
    NEW_INSTANCE_ID = instance_ids[0]
    # update ssm parameter store value with new instance id
    ssm_response = ssm.put_parameter(
     Name=SSM_PARAMETER_NAME,
     Value=NEW_INSTANCE_ID,
     Type='String',
     Overwrite=True
    )