Added support for getting minimum disk size for image.

Fix for: https://github.com/gvlproject/cloudbridge/issues/4

cloudbridge/cloud/interfaces/resources.py

@@ -742,6 +742,17 @@ class MachineImage(ObjectLifeCycleMixin, CloudResource):
         """
         pass
 
+    @abstractproperty
+    def min_disk(self):
+        """
+        Returns the minimum size of the disk that's required to
+        boot this image (in GB)
+
+        :rtype: ``int``
+        :return: The minimum disk size needed by this image
+        """
+        pass
+
     @abstractmethod
     def delete(self):
         """
@@ -2167,4 +2178,3 @@ class Bucket(PageableObjectMixin, CloudResource):
         :return: The newly created bucket object
         """
         pass
-

cloudbridge/cloud/providers/aws/resources.py

@@ -85,6 +85,18 @@ class AWSMachineImage(BaseMachineImage):
         """
         return self._ec2_image.description
 
+    @property
+    def min_disk(self):
+        """
+        Returns the minimum size of the disk that's required to
+        boot this image (in GB)
+
+        :rtype: ``int``
+        :return: The minimum disk size needed by this image
+        """
+        bdm = self._ec2_image.block_device_mapping
+        return bdm[self._ec2_image.root_device_name].size
+
     def delete(self):
         """
         Delete this image

cloudbridge/cloud/providers/openstack/resources.py

@@ -80,6 +80,17 @@ class OpenStackMachineImage(BaseMachineImage):
         """
         return None
 
+    @property
+    def min_disk(self):
+        """
+        Returns the minimum size of the disk that's required to
+        boot this image (in GB)
+
+        :rtype: ``int``
+        :return: The minimum disk size needed by this image
+        """
+        return self._os_image.minDisk
+
     def delete(self):
         """
         Delete this image

test/test_image_service.py

@@ -3,6 +3,7 @@ import uuid
 import six
 
 from cloudbridge.cloud.interfaces import MachineImageState
+from cloudbridge.cloud.interfaces import TestMockHelperMixin
 
 from test.helpers import ProviderTestBase
 import test.helpers as helpers
@@ -93,6 +94,11 @@ class CloudImageServiceTestCase(ProviderTestBase):
                     " not as expected: {2}" .format(found_images[0].name,
                                                     get_img.name,
                                                     test_image.name))
+                # TODO: Fix moto so that the BDM is populated correctly
+                if not isinstance(self.provider, TestMockHelperMixin):
+                    # check image size
+                    self.assertGreater(get_img.min_disk, 0, "Minimum disk size"
+                                       " required by image is invalid")
             # TODO: Images take a long time to deregister on EC2. Needs
             # investigation
             images = self.provider.compute.images.list()