storage: add wrappers for volume allocation and capacity

ccnode/interface.py

@@ -289,3 +289,25 @@ class HVStorage(object):
         :type volume_name: :class:`str`
         :return: :class:`str` path to the volume file
         '''
+        
+    def get_volume_allocation(self, pool, vol_name):
+        '''
+        Returns the pool space used by this volume in bytes
+
+        :param pool: the pool containing this volume from
+        :type pool: :class:`virStoragePool`
+        :param vol_name: name of the volume to query
+        :type vol_name: :class:`str`
+        :return: :class:`int` of allocation in bytes
+        '''
+        
+    def get_volume_capacity(self, pool, vol_name):
+        '''
+        Returns the capacity (usable space) of this volume in bytes
+
+        :param pool: the pool containing this volume from
+        :type pool: :class:`virStoragePool`
+        :param vol_name: name of the volume to query
+        :type vol_name: :class:`str`
+        :return: :class:`int` of capacity in bytes
+        '''

ccnode/libvirtwrapper.py

@@ -504,6 +504,43 @@ class LibvirtHVStorage(HVStorage):
         except libvirt.libvirtError as e:
             raise StorageError("Volume has no path information (%s)" % e)
 
+    def get_volume_allocation(self, pool, vol_name):
+        '''
+        Returns the pool space used by this volume in bytes
+
+        :param pool: the pool containing this volume from
+        :type pool: :class:`virStoragePool`
+        :param vol_name: name of the volume to query
+        :type vol_name: :class:`str`
+        :return: :class:`int` of allocation in bytes
+        '''
+        try:
+            vol = pool.storageVolLookupByName(vol_name)
+        except libvirt.libvirtError as e:
+            raise StorageError("Volume not found (%s)" % e)
+        try:
+            return vol.info()[2]
+        except libvirt.libvirtError as e:
+            raise StorageError("Volume has no allocation information (%s)" % e)
+
+    def get_volume_capacity(self, pool, vol_name):
+        '''
+        Returns the capacity (usable space) of this volume in bytes
+
+        :param pool: the pool containing this volume from
+        :type pool: :class:`virStoragePool`
+        :param vol_name: name of the volume to query
+        :type vol_name: :class:`str`
+        :return: :class:`int` of capacity in bytes
+        '''
+        try:
+            vol = pool.storageVolLookupByName(vol_name)
+        except libvirt.libvirtError as e:
+            raise StorageError("Volume not found (%s)" % e)
+        try:
+            return vol.info()[1]
+        except libvirt.libvirtError as e:
+            raise StorageError("Volume has no capacity information (%s)" % e)
 
 #### Helper functions