avocado.utils.vmimage
This utility provides an API to download/cache VM images (QCOW) from the official distributions repositories.
Basic Usage
Import vmimage
module:
>>> from avocado.utils import vmimage
Get an image, which consists in an object with the path of the downloaded/cached base image and the path of the external snapshot created out of that base image:
>>> image = vmimage.Image.from_parameters()
>>> image
<Image name=Fedora version=35 arch=x86_64>
>>> image.name
'Fedora'
>>> image.path
'/tmp/by_location/951337e4bd3f30b584623d46f1745147cb32aca5/Fedora-Cloud-Base-35-1.2.x86_64-54d81da8.qcow2'
>>> image.version
35
>>> image.base_image
'/tmp/by_location/951337e4bd3f30b584623d46f1745147cb32aca5/Fedora-Cloud-Base-35-1.2.x86_64.qcow2'
If you provide more details about the image, the object is expected to reflect those details:
>>> image = vmimage.Image.from_parameters(arch='aarch64)
>>> image
<Image name=Fedora version=35 arch=aarch64>
>>> image.name
'Fedora'
>>> image.path
'/tmp/by_location/3f1d3b1b568ad908eb003d1012ba79e1f3bb0d57/Fedora-Cloud-Base-35-1.2.aarch64-dab7007f.qcow2'
>>> image = vmimage.Image.from_parameters(version=34,name='fedora')
>>> image
<Image name=Fedora version=34 arch=x86_64>
>>> image.path
'/tmp/by_location/def0ea887952961473cfbfda268e77d66f9bcd14/Fedora-Cloud-Base-34-1.2.x86_64-0ed30cd9.qcow2'
Notice that, unlike the base_image
attribute, the path
attribute
will be always different in each instance, as it actually points to an
external snapshot created out of the base image:
>>> i1 = vmimage.Image.from_parameters()
>>> i2 = vmimage.Image.from_parameters()
>>> i1.path == i2.path
False
Custom Image Provider
If you need your own Image Provider, you can extend the
vmimage.IMAGE_PROVIDERS
list, including your provider class. For instance,
using the vmimage
utility in an Avocado test, we could add our own provider
with:
from avocado import Test
from avocado.utils import vmimage
class MyProvider(vmimage.ImageProviderBase):
name = 'MyDistro'
def __init__(self, version='[0-9]+', build='[0-9]+.[0-9]+',
arch=os.uname()[4]):
"""
:params version: The regular expression that represents
your distro version numbering.
:params build: The regular expression that represents
your build version numbering.
:params arch: The default architecture to look images for.
"""
super(MyProvider, self).__init__(version, build, arch)
# The URL which contains a list of the distro versions
self.url_versions = 'https://dl.fedoraproject.org/pub/fedora/linux/releases/'
# The URL which contains a list of distro images
self.url_images = self.url_versions + '{version}/CloudImages/{arch}/images/'
# The images naming pattern
self.image_pattern = 'Fedora-Cloud-Base-{version}-{build}.{arch}.qcow2$'
class MyTest(Test):
def setUp(self):
vmimage.IMAGE_PROVIDERS.add(MyProvider)
image = vmimage.get('MyDistro')
...
def test(self):
...
Supported images
The vmimage library has no hardcoded limitations of versions or architectures that can be supported. You can use it as you wish. This is the list of images that we tested and they work with vmimage:
Provider |
Version |
Architecture |
---|---|---|
None |
None |
None |