Get AWS Account ID from Boto

Thanks to @louahola for the improvement on my initial answer.

This will get you the Account ID for your key pair:

import boto3

sts = boto3.client(
    "sts", aws_access_key_id=ACCESS_KEY, aws_secret_access_key=SECRET_KEY,
)
account_id = sts.get_caller_identity()["Account"]

If you are running on an EC2 instance with IAM role-based permissions or any of boto3's other credential options, you can do this even easier:

import boto3

account_id = boto3.client("sts").get_caller_identity()["Account"]

Something like this will work:

import boto3

ACCESS_KEY = 'FOO'
SECRET_KEY = 'BAR'

iam = boto3.resource('iam',
    aws_access_key_id=ACCESS_KEY,
    aws_secret_access_key=SECRET_KEY,
)
account_id = iam.CurrentUser().arn.split(':')[4]

print account_id

If you use EC2 IAM roles, you can omit all of the access/secret key stuff and the code becomes simply:

iam = boto3.resource('iam')
account_id = iam.CurrentUser().arn.split(':')[4]

The AccountID can be grabbed from the get-caller-identity sts function. This returns an "Account" field:

client = boto3.client("sts", aws_access_key_id=access_key, aws_secret_access_key=secret_key)
account_id = client.get_caller_identity()["Account"]