Get a list of instances in an AWS autoscaling group, with boto3. I set MaxRecords=2 to experiment with the pagination, it does seem to return the whole list when not set, but.....

stupidboto3.py

import boto3


def as_get_instances(client, asgroup, NextToken = None):
    # this is downright ridiculous because boto3 sucks

    irsp = None
    if NextToken:
        irsp = client.describe_auto_scaling_instances(MaxRecords=2, NextToken=NextToken)
    else:
        irsp = client.describe_auto_scaling_instances(MaxRecords=2)

    for i in irsp['AutoScalingInstances']:
        if i['AutoScalingGroupName'] == asgroup:
            yield i['InstanceId']

    if 'NextToken' in irsp:
        for i in as_get_instances(client, asgroup, NextToken = irsp['NextToken']):
            yield i


if __name__ == '__main__':
    client = boto3.client('autoscaling', region_name='us-east-1')
    print(list(as_get_instances(client, 'content_server')))

You should be able to make this a tiny bit cleaner via get_paginator

You should be able to make this a tiny bit cleaner via get_paginator

A very basic approach (you can max PageSize to 50 in production):

import boto3

def asg_get_instances(asgroup):
    awsclient = boto3.client('autoscaling')
    asg_paginator = awsclient.get_paginator("describe_auto_scaling_instances")
    asg_page_iterator = asg_paginator.paginate( PaginationConfig={'PageSize':1, 'StartingToken': None } )
    asg_instances = []
    for asg_page in asg_page_iterator:
        all_asg_instances += asg_page['AutoScalingInstances']

    res = []
    for ec2 in all_asg_instances:
        if ec2['AutoScalingGroupName'] == asgroup:
            res += ec2

    return res