Synnefo

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from django.core.management.base import BaseCommand, CommandError

from synnefo.management import common

from synnefo.logic import backend as backend_mod

from synnefo.db.models import Backend

from django.db import transaction, models

HELP_MSG = """\

Remove a backend from the Database. Backend should be set to drained before

trying to remove it, in order to avoid the allocation of a new instances in

this Backend.  Removal of a backend will fail if the backend hosts any

non-deleted instances."""

class Command(BaseCommand):

    help = HELP_MSG

    def handle(self, *args, **options):

        write = self.stdout.write

        if len(args) < 1:

            raise CommandError("Please provide a backend ID")

        backend = common.get_resource("backend", args[0], for_update=True)

        write("Trying to remove backend: %s\n" % backend.clustername)

        if backend.virtual_machines.filter(deleted=False).exists():

            raise CommandError('Backend hosts non-deleted vms. Cannot delete')

        # Get networks before deleting backend, because after deleting the

        # backend, all BackendNetwork objects are deleted!

        networks = [bn.network for bn in backend.networks.all()]

        try:

            delete_backend(backend)

        except models.ProtectedError as e:

            msg = ("Cannot delete backend because it contains"

                   "non-deleted VMs:\n%s" % e)

            raise CommandError(msg)

        write('Successfully removed backend from DB.\n')

        if networks:

            write("Clearing networks from %s..\n" % backend.clustername)

            for network in networks:

                backend_mod.delete_network(network=network, backend=backend)

            write("Successfully issued jobs to remove all networks.\n")

@transaction.commit_on_success

def delete_backend(backend):

    # Get X-Lock

    backend = Backend.objects.select_for_update().get(id=backend.id)

    # Clear 'backend' field of 'deleted' VirtualMachines

    backend.virtual_machines.filter(deleted=True).update(backend=None)

    # Delete all BackendNetwork objects of this backend

    backend.networks.all().delete()

    backend.delete()