#   Copyright (c) 2013-2015, Intel Performance Learning Solutions Ltd, Intel Corporation.
#
#   Licensed under the Apache License, Version 2.0 (the "License");
#   you may not use this file except in compliance with the License.
#   You may obtain a copy of the License at
#
#       http://www.apache.org/licenses/LICENSE-2.0
#
#   Unless required by applicable law or agreed to in writing, software
#   distributed under the License is distributed on an "AS IS" BASIS,
#   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
#   See the License for the specific language governing permissions and
#   limitations under the License.

"""
Module for the Provisioning of Service Instance.
"""

__author__ = 'tmetsch'

import abc
import paramiko


class Provisioner(object):
    """
    Module to allow for provisioning of SICs.
    """

    @abc.abstractmethod
    def provision(self, endpoint, artifacts):
        """
        Provision an SIC.

        :param endpoint: Endpoint of the SIC to be provisioned.
        :param artifacts: description of the provisioning steps.
        """
        raise NotImplementedError('To be implemented.')


class SshProvisioner(Provisioner):
    """
    Example SSH based provsioner.
    """

    def provision(self, endpoint, artifacts, **kwargs):
        if 'look_for_keys' not in kwargs:
            kwargs['look_for_keys'] = False
        client = paramiko.SSHClient()
        client.set_missing_host_key_policy(paramiko.AutoAddPolicy())
        client.connect(endpoint, **kwargs)
        stdin, stdout, stderr = client.exec_command(artifacts)
        return stdout.read()
