Change many aws instances tags (boto3)

tags.py

import boto3
import sys

ec2 = boto3.client('ec2')

# Grab where backup retention is 14 days so we can reduce it to 7
instances = ec2.describe_instances(Filters=[{'Name': 'tag:Retention', 'Values': ['14']}])

ids = []

for reservation in instances['Reservations']:
    for instance in reservation['Instances']:
        ids.append(instance['InstanceId'])

print "Changing tags for %d instances" % len(ids)

ec2.create_tags(
    Resources=ids,
    Tags=[
        {
            'Key': 'Retention',
            'Value': '7'
        }
    ]
)

This assumes you have ~/.aws/credentials setup.

I ran this like so:

export AWS_DEFAULT_PROFILE="a-specific-profile"
export AWS_DEFAULT_REGION="us-east-1"
python tags.py

What would this look like if I wanted to edit specific tags on a specific set of instance IDs passed either from a text file or passed as an argument?

@dad2jrn If passing them as input on the CLI lookup pythons arg parser. If passing them via file it depends on the format. JSON, YAML, CSV? Basically, you would read the file into python using...

with open('data.txt', 'r') as myfile:
  data = myfile.read()

You could then take that data file and turn it into json. (if it's json format)

import json
data = json.load(data)