assume-role-with-API-call

assume-role-with-API-call.py

import boto3

# The calls to AWS STS AssumeRole must be signed with the access key ID
# and secret access key of an existing IAM user or by using existing temporary 
# credentials such as those from antoher role. (You cannot call AssumeRole 
# with the access key for the root account.) The credentials can be in 
# environment variables or in a configuration file and will be discovered 
# automatically by the boto3.client() function. For more information, see the 
# Python SDK documentation: 
# http://boto3.readthedocs.io/en/latest/reference/services/sts.html#client

# create an STS client object that represents a live connection to the 
# STS service
sts_client = boto3.client('sts')

# Call the assume_role method of the STSConnection object and pass the role
# ARN and a role session name.
assumedRoleObject = sts_client.assume_role(
    RoleArn="arn:aws:iam::account-of-role-to-assume:role/name-of-role",
    RoleSessionName="AssumeRoleSession1"
)

# From the response that contains the assumed role, get the temporary 
# credentials that can be used to make subsequent API calls
credentials = assumedRoleObject['Credentials']

# Use the temporary credentials that AssumeRole returns to make a 
# connection to Amazon S3  
s3_resource = boto3.resource(
    's3',
    aws_access_key_id = credentials['AccessKeyId'],
    aws_secret_access_key = credentials['SecretAccessKey'],
    aws_session_token = credentials['SessionToken'],
)

# Use the Amazon S3 resource object that is now configured with the 
# credentials to access your S3 buckets. 
for bucket in s3_resource.buckets.all():
    print(bucket.name)