[Kimchi-devel] [PATCH 7/8] Check QEMU stream DNS capability when attaching new disk to guest

[Paulo Ricardo Paz Vital]

On Tue, 2014-10-28 at 10:43 -0200, Aline Manera wrote:
> When QEMU is not able to solve hostname for a remote CDROM path, we need
> to convert the hostname to IP to avoid problems.
> To make xmlutils/ independent of model instances, that verification must
> be done prior to the XML generation.
> 
> Signed-off-by: Aline Manera <alinefm at linux.vnet.ibm.com>
> ---
>  src/kimchi/model/vmstorages.py | 16 ++++++++++++++++
>  tests/test_model.py            | 11 ++++++++++-
>  2 files changed, 26 insertions(+), 1 deletion(-)
> 
> diff --git a/src/kimchi/model/vmstorages.py b/src/kimchi/model/vmstorages.py
> index 70240b0..576d66d 100644
> --- a/src/kimchi/model/vmstorages.py
> +++ b/src/kimchi/model/vmstorages.py
> @@ -17,12 +17,15 @@
>  # License along with this library; if not, write to the Free Software
>  # Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301 USA
> 
> +import socket
>  import string
> +import urlparse
> 
>  from lxml import etree
> 
>  from kimchi.exception import InvalidOperation, InvalidParameter, NotFoundError
>  from kimchi.exception import OperationFailed
> +from kimchi.model.config import CapabilitiesModel
>  from kimchi.model.vms import DOM_STATE_MAP, VMModel
>  from kimchi.model.storagevolumes import StorageVolumeModel
>  from kimchi.model.utils import get_vm_config_flag
> @@ -122,6 +125,13 @@ class VMStoragesModel(object):
>              params['path'] = vol_info['path']
> 
>          params.update(self._get_available_bus_address(params['bus'], vm_name))
> +
> +        # Check QEMU can resolve hostname
> +        hostname = urlparse.urlparse(params['path']).hostname
> +        if hostname is not None and not CapabilitiesModel().qemu_stream_dns:
> +            ip = socket.gethostbyname(hostname)
> +            params['path'] = params['path'].replace(hostname, ip)
> +
>          # Add device to VM
>          dev, xml = get_disk_xml(params)
>          try:
> @@ -178,6 +188,12 @@ class VMStorageModel(object):
>          params['path'] = params.get('path', '')
>          dev_info.update(params)
> 
> +        # Check QEMU can resolve hostname
> +        hostname = urlparse.urlparse(params['path']).hostname
> +        if hostname is not None and not CapabilitiesModel().qemu_stream_dns:
> +            ip = socket.gethostbyname(hostname)
> +            params['path'] = params['path'].replace(hostname, ip)
> +

The same block of code in two different parts? Why not create a new
function on utils a function to do this check?

One more question? Shouldn't the "dev_info.update(params)" line moved to
be after the "Check QEMU can resolve hostname" block? Looks like the
params['path'] will contain the wrong value if the "if" statement is
true.

>          dev, xml = get_disk_xml(dev_info)
>          try:
>              dom.updateDeviceFlags(xml, get_vm_config_flag(dom, 'all'))
> diff --git a/tests/test_model.py b/tests/test_model.py
> index e407fe5..f094ed7 100644
> --- a/tests/test_model.py
> +++ b/tests/test_model.py
> @@ -25,9 +25,11 @@ import psutil
>  import pwd
>  import re
>  import shutil
> +import socket
>  import tempfile
>  import threading
>  import time
> +import urlparse
>  import unittest
>  import uuid
> 
> @@ -433,7 +435,14 @@ class ModelTests(unittest.TestCase):
>                                    {'path': valid_remote_iso_path})
>              cdrom_info = inst.vmstorage_lookup(vm_name, cdrom_dev)
>              cur_cdrom_path = re.sub(":80/", '/', cdrom_info['path'])
> -            self.assertEquals(valid_remote_iso_path, cur_cdrom_path)
> +
> +            # As Kimchi server is not running during this test case
> +            # CapabilitiesModel.qemu_stream_dns will be always False
> +            # so we need to convert the hostname to IP
> +            output = urlparse.urlparse(valid_remote_iso_path)
> +            hostname = socket.gethostbyname(output.hostname)
> +            url = valid_remote_iso_path.replace(output.hostname, hostname)
> +            self.assertEquals(url, cur_cdrom_path)
> 
>      @unittest.skipUnless(utils.running_as_root(), 'Must be run as root')
>      def test_vm_storage_provisioning(self):