ec2stack/providers/cloudstack/instances.py

#!/usr/bin/env python
# encoding: utf-8

from ec2stack.providers import cloudstack
from ec2stack.providers.cloudstack import requester, service_offerings, zones

from ec2stack import helpers, errors


@helpers.authentication_required
def describe_instances():
    args = {'command': 'listVirtualMachines'}
    response = cloudstack.describe_item(
        args, 'virtualmachine', errors.invalid_instance_id, 'InstanceId'
    )

    return _describe_instances_response(
        response
    )


def describe_instance_by_id(instance_id):
    args = {'id': instance_id, 'command': 'listVirtualMachines'}
    response = cloudstack.describe_item_request(
        args, 'virtualmachine', errors.invalid_instance_id
    )
    return response


def _describe_instances_response(response):
    return {
        'template_name_or_list': 'instances.xml',
        'response_type': 'DescribeInstancesResponse',
        'response': response
    }


@helpers.authentication_required
def describe_instance_attribute():
    helpers.require_parameters(['InstanceId', 'Attribute'])
    instance_id = helpers.get('InstanceId')
    response = describe_instance_by_id(instance_id)
    return _describe_instance_attribute_response(response)


def _describe_instance_attribute_response(response):
    attribute = helpers.get('Attribute')
    if attribute not in response.keys():
        errors.invalid_paramater_value(
            'The specified attribute is not valid, please specify a valid ' +
            'instance attribute like \'name\' or \'state\'')

    response = {
        'template_name_or_list': 'instance_attribute.xml',
        'response_type': 'DescribeInstanceAttributeResponse',
        'attribute': attribute,
        'id': response['id'],
        'value': response[attribute]
    }

    return response


@helpers.authentication_required
def run_instance():
    helpers.require_parameters(['ImageId',
                                'Placement.AvailabilityZone',
                                'InstanceType'])
    response = _run_instance_request()
    return _run_instance_response(response)


def _run_instance_request():
    args = {}

    availibity_zone_name = helpers.get('Placement.AvailabilityZone')
    service_offering_name = helpers.get('InstanceType')

    args['zoneid'] = zones.get_zone(availibity_zone_name)['id']
    args['serviceofferingid'] = \
        service_offerings.get_service_offering(service_offering_name)['id']

    args['templateid'] = helpers.get('ImageId')
    args['command'] = 'deployVirtualMachine'

    response = requester.make_request_async(args)

    response = response['virtualmachine']

    return response


def _run_instance_response(response):
    response = {
        'template_name_or_list': 'run_instance.xml',
        'response_type': 'RunInstancesResponse',
        'response': response
    }

    return response


@helpers.authentication_required
def start_instance():
    helpers.require_parameters(['InstanceId.1'])
    instance_id = helpers.get('InstanceId.1')
    previous_instance_state_description = describe_instance_by_id(instance_id)
    new_instance_state_description = _start_instance_request(instance_id)
    return _start_instance_response(
        previous_instance_state_description,
        new_instance_state_description
    )


def _start_instance_request(instance_id):
    args = {'command': 'startVirtualMachine',
            'id': instance_id}

    response = requester.make_request_async(args)

    response = response['virtualmachine']

    return response


def _start_instance_response(previous_state, new_state):
    response = {
        'template_name_or_list': 'change_instance_state.xml',
        'response_type': 'StartInstancesResponse',
        'previous_state': previous_state,
        'new_state': new_state
    }

    return response


@helpers.authentication_required
def terminate_instance():
    helpers.require_parameters(['InstanceId.1'])
    instance_id = helpers.get('InstanceId.1')
    previous_instance_state_description = describe_instance_by_id(instance_id)
    new_instance_state_description = _terminate_instance_request(instance_id)
    return _terminate_instance_response(
        previous_instance_state_description,
        new_instance_state_description
    )


def _terminate_instance_request(instance_id):
    args = {'command': 'destroyVirtualMachine',
            'id': instance_id}

    response = requester.make_request_async(args)

    response = response['virtualmachine']

    return response


def _terminate_instance_response(previous_state, new_state):
    response = {
        'template_name_or_list': 'change_instance_state.xml',
        'response_type': 'TerminateInstancesResponse',
        'previous_state': previous_state,
        'new_state': new_state
    }

    return response