Method to determine your AWS account ID using boto3 for either a user or an ec2 instance or lambda function

01_get_account_id_for_user_ec2instance_role_or_lambda.py

import boto3
print(boto3.client('sts').get_caller_identity()['Account'])

02_get_account_id.bash

aws sts get-caller-identity --query 'Account' --output text

03_deprecated_get_account_id_lambda.py

# This method is no longer needed with the release of the STS GetCallerIdentity method

def get_account_id(context):
  return context.invoked_function_arn.split(':')[4]

def lambda_handler(event, context):
  print("My account ID is %s" % get_account_id(context))

04_deprecated_get_account_id_user_or_ec2_boto3.py

# This method is no longer needed with the release of the STS GetCallerIdentity method

from botocore.vendored import requests
import boto3

def get_account_id():
    try:
        # We're running in an ec2 instance, get the account id from the
        # instance profile ARN
        return requests.get(
            'http://169.254.169.254/latest/meta-data/iam/info/',
            timeout=1).json()['InstanceProfileArn'].split(':')[4]
    except:
        pass

    try:
        # We're not on an ec2 instance but have api keys, get the account
        # id from the user ARN
        return boto3.client('iam').get_user()['User']['Arn'].split(':')[4]
    except:
        pass

    return False

05_deprecated_get_account_id_user_or_ec2_boto3_urllib2.py

# This method is no longer needed with the release of the STS GetCallerIdentity method

import urllib2, json
import boto3

def get_account_id():
    try:
        # We're running in an ec2 instance, get the account id from the
        # instance profile ARN
        return json.loads(urllib2.urlopen(
            'http://169.254.169.254/latest/meta-data/iam/info/', 
            None, 
            1).read())['InstanceProfileArn'].split(':')[4]
    except:
        pass

    try:
        # We're not on an ec2 instance but have api keys, get the account
        # id from the user ARN
        return boto3.client('iam').get_user()['User']['Arn'].split(':')[4]
    except:
        pass

    return False