Source code for gcloud_utils.compute

"""Module to handle Google Compute Service"""
import time
import logging
from googleapiclient import discovery

logging.basicConfig(level=logging.DEBUG,
                    format='%(asctime)s - %(levelname)s - %(name)s - %(message)s')


class Compute(object):
    """Google-compute-engine handler"""

    def __init__(self, project, zone):
        self.project = project
        self.zone = zone
        self.logger = logging.getLogger(name=self.__class__.__name__)
        self.client = discovery.build('compute', 'v1')
        self.__update_instances(self.client)

    def __request_instances_info(self, client):
        instances = client.instances().list(
            project=self.project, zone=self.zone).execute()
        return instances[u'items']

    def __update_instances(self, client):
        intances_itens = self.__request_instances_info(client)
        result = {}
        for i in intances_itens:
            result.update({i[u'name']: i[u'status']})
        self.intances = result

    def __check_status(self, instance_name, expected_status, max_time=400):
        sleep_time = 10
        max_check = max_time/sleep_time
        i = 0
        while (not self.intances[instance_name] == expected_status) and (i <= max_check):
            self.logger.info("waiting to %s ...", expected_status)
            self.__update_instances(self.client)
            time.sleep(sleep_time)
            i += 1

        return True

    def __change_status(self, instance_name, action, expecte_status):
        try:
            status = self.intances[instance_name]
            self.logger.debug("%s status: %s", instance_name, status)

            if not status == expecte_status:
                action(zone=self.zone, project=self.project,
                       instance=instance_name).execute()
                self.__check_status(instance_name, expecte_status)

        except KeyError:
            raise Exception("Instence %s doesn't exists" % instance_name)

    def start_instance(self, instance_name):
        """Start VM by name"""
        self.__change_status(
            instance_name, self.client.instances().start, "RUNNING")

    def stop_instance(self, instance_name):
        """Stop VM by name"""
        self.__change_status(
            instance_name, self.client.instances().stop, "TERMINATED")