AWS STS assume role "unable to locate credentials" in docker container

Question

I am trying to fetch aws credentials using aws sts. The below code works fine in Pycharm, but when i run it in docker container i am getting "unable to locate credentials."

def assumed_role_session(role_arn):
    try:
        base_session = boto3.session.Session()._session.profile
        sts_client = boto3.client('sts').assume_role(RoleArn=role_arn, RoleSessionName=base_session)
        credentials = sts_client['Credentials']
        return credentials
    except Exception as e:
        return None

assumed_role_session('arn:aws:iam::{AWS_ACCOUNT_NUMBER}:role/{AWS_ROLE_NAME}')

Answer 1

When running the python app in docker container, the boto3 lib will try to fetch the credentials from the docker container env, not the local PC env. So, you will need to check if the credentials have been configured correctly via the Dockerfile / docker-compose yml file.

Besides, Boto3 will search for credentials in a particular order. (check https://boto3.amazonaws.com/v1/documentation/api/latest/guide/credentials.html) Please make sure that the credential configuration you are going to use always has the 1st priority.