Synnefo

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import logging

from snf_django.lib.api import faults

from django.conf import settings

from synnefo.logic import backend, commands

log = logging.getLogger(__name__)

@commands.server_command("ATTACH_VOLUME")

def attach_volume(vm, volume):

    """Attach a volume to a server.

    The volume must be in 'AVAILABLE' status in order to be attached. Also,

    number of the volumes that are attached to the server must remain less

    than 'GANETI_MAX_DISKS_PER_INSTANCE' setting. This function will send

    the corresponding job to Ganeti backend and update the status of the

    volume to 'ATTACHING'.

    """

    # Check volume state

    if volume.status not in ["AVAILABLE", "CREATING"]:

        raise faults.BadRequest("Cannot attach volume while volume is in"

                                " '%s' status." % volume.status)

    # Check that disk templates are the same

    if volume.disk_template != vm.flavor.disk_template:

        msg = ("Volume and server must have the same disk template. Volume has"

               " disk template '%s' while server has '%s'"

               % (volume.disk_template, vm.flavor.disk_template))

        raise faults.BadRequest(msg)

    # Check maximum disk per instance hard limit

    if vm.volumes.filter(deleted=False).count() == settings.GANETI_MAX_DISKS_PER_INSTANCE:

        raise faults.BadRequest("Maximum volumes per server limit reached")

    jobid = backend.attach_volume(vm, volume)

    log.info("Attached volume '%s' to server '%s'. JobID: '%s'", volume.id,

             volume.machine_id, jobid)

    volume.backendjobid = jobid

    volume.machine = vm

    volume.status = "ATTACHING"

    volume.save()

    return jobid

@commands.server_command("DETACH_VOLUME")

def detach_volume(vm, volume):

    """Detach a volume to a server.

    The volume must be in 'IN_USE' status in order to be detached. Also,

    the root volume of the instance (index=0) can not be detached. This

    function will send the corresponding job to Ganeti backend and update the

    status of the volume to 'DETACHING'.

    """

    _check_attachment(vm, volume)

    if volume.status != "IN_USE":

        #TODO: Maybe allow other statuses as well ?

        raise faults.BadRequest("Cannot detach volume while volume is in"

                                " '%s' status." % volume.status)

    if volume.index == 0:

        raise faults.BadRequest("Cannot detach the root volume of a server")

    jobid = backend.detach_volume(vm, volume)

    log.info("Detached volume '%s' from server '%s'. JobID: '%s'", volume.id,

             volume.machine_id, jobid)

    volume.backendjobid = jobid

    volume.status = "DETACHING"

    volume.save()

    return jobid

def _check_attachment(vm, volume):

    """Check that volume is attached to vm."""

    if volume.machine_id != vm.id:

        raise faults.BadRequest("Volume '%s' is not attached to server '%s'"

                                % volume.id, vm.id)