boto3 how to retrieve the elastic ip from an instance

Question

I need to do the following:

I have some instances that contain a certain tag, I need to loop through those instances and for each instance which contains that certain tag, if that instance has an elastic ip attached, I need to tag that elastic ip with that same tag. My code is the following:

import boto3
import json

region_list = ['us-east-1']
session = boto3.Session(profile_name='default')

for region in region_list:
    ec2 = session.resource('ec2',region)
    client = boto3.client('ec2',region)
    # Retrieve instances that contain this specific tag
    instances = ec2.instances.filter(Filters=[{'Name':'tag:MyTargetTag', 'Values':['*']}])

    for instance in instances:
        for tag in instance.tags:
            if tag['Key'] == "MyTargetTag":
                MyTargetTag = tag['Value']
        ## check if this instance has an elasticip
        ## if it has, assign the value of MyTargetTag to it
        response = client.add_tags(
            ResourceArns=[
                #elasticip ip identifier of some sort,
            ],
            Tags=[
                {
                    'Key': 'MyTargetTag',
                    'Value': MyTargetTag
                },
            ]
        )

I've read through the docs and videos and what not but honestly I don't understand it quite completely and I'm just doing trial and error without any success.

Answer 1

You may access VPC or classic Elastic IPs on the boto3.resource('ec2') resources vpc_addresses and classic_addresses respectively.

If the addresses are associated, they will have an instance_id attribute. You'll be able to get the tags with ec2.Instance(address.instance_id).tags

If you want to go through all addresses, the boto3.client('ec2') client has describe_addresses that will give you the same information.