subclass of botocore.session.Session that assumes roles and refreshes credentials

assumerole.py

from botocore.session import Session

credentials_cache = dict()

class Session(Session):
    def __init__(self, role_arn, *args, **kwargs):
        super().__init__(*args, **kwargs)
        self._config = dict(
            profiles=dict(
                default=dict(
                    credential_source="Ec2InstanceMetadata",
                    role_arn=role_arn,
                )
            )
        )
        self.get_component("credential_provider").get_provider(
            "assume-role"
        ).cache = credentials_cache

    @classmethod
    def from_role(cls, *args, **kwargs):
        arn = _role_arn(*args, **kwargs)
        return cls(arn)