tag_all_loggroups.py

#!/usr/bin/env python3
import os
import boto3
import botocore

def paginate(method, **kwargs):
    """ Generic boto paginator class """
    client = method.__self__
    paginator = client.get_paginator(method.__name__)
    for page in paginator.paginate(**kwargs).result_key_iters():
        for result in page:
            yield result

def main():
    # Boto3 MFA session magic
    working_dir = os.path.join(os.path.expanduser('~'), '.aws/cli/cache')

    session = botocore.session.get_session()
    provider = session.get_component('credential_provider').get_provider('assume-role')
    provider.cache = botocore.credentials.JSONFileCache(working_dir)

    session = boto3.Session(botocore_session=session)
    logs = session.client('logs')

    for log_group in  paginate(logs.describe_log_groups):
        group = log_group['logGroupName']
        print(group)
        res = logs.list_tags_log_group(
            logGroupName=group
        )
        if res['tags'] == {}:
            logs.tag_log_group(
                logGroupName=group,
                tags={
                    'CustomerProject': ('GLK%s' % group) # CustomerProject is an AWS cost tag here
                }
            )
        else:
            print(res['tags'])

if __name__ == '__main__':
    main()