features: client-side API

qubesmgmt/exc.py

@@ -103,6 +103,10 @@ class QubesMemoryError(QubesException, MemoryError):
     '''Cannot start domain, because not enough memory is available'''
 
 
+class QubesFeatureNotFoundError(QubesException, KeyError):
+    '''Feature not set for a given domain'''
+
+
 class StoragePoolException(QubesException):
     ''' A general storage exception '''
 

qubesmgmt/features.py

@@ -0,0 +1,69 @@
+# -*- encoding: utf8 -*-
+#
+# The Qubes OS Project, http://www.qubes-os.org
+#
+# Copyright (C) 2017 Marek Marczykowski-Górecki
+#                               <marmarek@invisiblethingslab.com>
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU Lesser General Public License as published by
+# the Free Software Foundation; either version 2.1 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU Lesser General Public License for more details.
+#
+# You should have received a copy of the GNU Lesser General Public License along
+# with this program; if not, see <http://www.gnu.org/licenses/>.
+
+'''VM features interface'''
+
+
+class Features(object):
+    '''Manager of the features.
+
+    Features can have three distinct values: no value (not present in mapping,
+    which is closest thing to :py:obj:`None`), empty string (which is
+    interpreted as :py:obj:`False`) and non-empty string, which is
+    :py:obj:`True`. Anything assigned to the mapping is coerced to strings,
+    however if you assign instances of :py:class:`bool`, they are converted as
+    described above. Be aware that assigning the number `0` (which is considered
+    false in Python) will result in string `'0'`, which is considered true.
+    '''
+    # pylint: disable=too-few-public-methods
+
+    def __init__(self, vm):
+        super(Features, self).__init__()
+        self.vm = vm
+
+    def __delitem__(self, key):
+        self.vm.qubesd_call(self.vm.name, 'mgmt.vm.feature.Remove', key)
+
+    def __setitem__(self, key, value):
+        self.vm.qubesd_call(self.vm.name, 'mgmt.vm.feature.Set', key, value)
+
+    def __getitem__(self, item):
+        return self.vm.qubesd_call(
+            self.vm.name, 'mgmt.vm.feature.Get', item).decode('utf-8')
+
+    def __iter__(self):
+        qubesd_response = self.vm.qubesd_call(self.vm.name,
+            'mgmt.vm.feature.List')
+        return iter(qubesd_response.decode('utf-8').splitlines())
+
+    keys = __iter__
+
+    _NO_DEFAULT = object()
+
+    def check_with_template(self, feature, default=_NO_DEFAULT):
+        ''' Check if the vm's template has the specified feature. '''
+        try:
+            qubesd_response = self.vm.qubesd_call(
+                self.vm.name, 'mgmt.vm.feature.CheckWithTemplate', feature)
+            return qubesd_response.decode('utf-8')
+        except KeyError:
+            if default is self._NO_DEFAULT:
+                raise
+            return default

qubesmgmt/vm/__init__.py

@@ -23,6 +23,7 @@
 import logging
 import qubesmgmt.base
 import qubesmgmt.storage
+import qubesmgmt.features
 
 
 class QubesVM(qubesmgmt.base.PropertyHolder):
@@ -30,10 +31,13 @@ class QubesVM(qubesmgmt.base.PropertyHolder):
 
     log = None
 
+    features = None
+
     def __init__(self, app, name):
         super(QubesVM, self).__init__(app, 'mgmt.vm.property.', name)
         self._volumes = None
         self.log = logging.getLogger(name)
+        self.features = qubesmgmt.features.Features(self)
 
     @property
     def name(self):