Class IMDSRegionProvider

awscli/utils.py:96–162

class IMDSRegionProvider(BaseProvider):
    def __init__(self, session, environ=None, fetcher=None):
        """Initialize IMDSRegionProvider.

        :type session: :class:`botocore.session.Session`
        :param session: The session is needed to look up configuration for
            how to contact the instance metadata service. Specifically the
            whether or not it should use the IMDS region at all, and if so how
            to configure the timeout and number of attempts to reach the
            service.

        :type environ: None or dict
        :param environ: A dictionary of environment variables to use. If
            ``None`` is the argument then ``os.environ`` will be used by
            default.

        :type fecther: :class:`botocore.utils.InstanceMetadataRegionFetcher`
        :param fetcher: The class to actually handle the fetching of the region
            from the IMDS. If not provided a default one will be created.
        """
        self._session = session
        if environ is None:
            environ = os.environ
        self._environ = environ
        self._fetcher = fetcher

    def provide(self):
        """Provide the region value from IMDS."""
        instance_region = self._get_instance_metadata_region()
        return instance_region

    def _get_instance_metadata_region(self):
        fetcher = self._get_fetcher()
        region = fetcher.retrieve_region()
        return region

    def _get_fetcher(self):
        if self._fetcher is None:
            self._fetcher = self._create_fetcher()
        return self._fetcher

    def _create_fetcher(self):
        metadata_timeout = self._session.get_config_variable(
            'metadata_service_timeout'
        )
        metadata_num_attempts = self._session.get_config_variable(
            'metadata_service_num_attempts'
        )
        imds_config = {
            'ec2_metadata_service_endpoint': self._session.get_config_variable(
                'ec2_metadata_service_endpoint'
            ),
            'ec2_metadata_service_endpoint_mode': resolve_imds_endpoint_mode(
                self._session
            ),
            'ec2_metadata_v1_disabled': self._session.get_config_variable(
                'ec2_metadata_v1_disabled'
            ),