Initial labels support

It's just first part - reading info about them. The missing part:
creating and removing.

qubesmgmt/app.py

@@ -28,6 +28,7 @@
 
 import qubesmgmt.base
 import qubesmgmt.vm
+import qubesmgmt.label
 import qubesmgmt.exc
 import qubesmgmt.utils
 
@@ -100,15 +101,19 @@ def keys(self):
         return self._vm_list.keys()
 
 
+
 class QubesBase(qubesmgmt.base.PropertyHolder):
     '''Main Qubes application'''
 
     #: domains (VMs) collection
     domains = None
+    #: labels collection
+    labels = None
 
     def __init__(self):
         super(QubesBase, self).__init__(self, 'mgmt.property.', 'dom0')
         self.domains = VMCollection(self)
+        self.labels = qubesmgmt.label.LabelsCollection(self)
 
 
 class QubesLocal(QubesBase):

qubesmgmt/label.py

@@ -0,0 +1,104 @@
+# -*- encoding: utf8 -*-
+#
+# The Qubes OS Project, http://www.qubes-os.org
+#
+# Copyright (C) 2017 Marek Marczykowski-Górecki
+#                               <[email protected]>
+#
+# 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 Labels'''
+
+import qubesmgmt.exc
+
+class Label(object):
+    '''Label definition for virtual machines
+
+    Label specifies colour of the padlock displayed next to VM's name.
+
+    :param str color: colour specification as in HTML (``#abcdef``)
+    :param str name: label's name like "red" or "green"
+    '''
+
+    def __init__(self, app, name):
+        self.app = app
+        self._name = name
+        self._color = None
+
+    @property
+    def color(self):
+        '''color specification as in HTML (``#abcdef``)'''
+        if self._color is None:
+            try:
+                qubesd_response = self.app.qubesd_call(
+                    'dom0', 'mgmt.label.Get', self._name, None)
+            except qubesmgmt.exc.QubesDaemonNoResponseError:
+                raise AttributeError
+            self._color = qubesd_response.decode()
+        return self._color
+
+    @property
+    def name(self):
+        '''label's name like "red" or "green"'''
+        return self._name
+
+    def __str__(self):
+        return self._name
+
+
+class LabelsCollection(object):
+    '''Collection of VMs objects'''
+    def __init__(self, app):
+        self.app = app
+        self._label_list = None
+        self._label_objects = {}
+
+    def clear_cache(self):
+        '''Clear cached list of labels'''
+        self._label_list = None
+
+    def refresh_cache(self, force=False):
+        '''Refresh cached list of VMs'''
+        if not force and self._label_list is not None:
+            return
+        label_list_data = self.app.qubesd_call('dom0', 'mgmt.label.List')
+        label_list_data = label_list_data.decode('ascii')
+        assert label_list_data[-1] == '\n'
+        self._label_list = label_list_data[:-1].splitlines()
+
+        for name, label in list(self._label_objects.items()):
+            if label.name not in self._label_list:
+                # Label no longer exists
+                del self._label_objects[name]
+
+    def __getitem__(self, item):
+        if item not in self:
+            raise KeyError(item)
+        if item not in self._label_objects:
+            self._label_objects[item] = Label(self.app, item)
+        return self._label_objects[item]
+
+    def __contains__(self, item):
+        self.refresh_cache()
+        return item in self._label_list
+
+    def __iter__(self):
+        self.refresh_cache()
+        for vm in self._label_list:
+            yield self[vm]
+
+    def keys(self):
+        '''Get list of label names.'''
+        self.refresh_cache()
+        return self._label_list.keys()

qubesmgmt/tests/tools/label.py

@@ -0,0 +1,53 @@
+# -*- encoding: utf8 -*-
+#
+# The Qubes OS Project, http://www.qubes-os.org
+#
+# Copyright (C) 2017 Marek Marczykowski-Górecki
+#                               <[email protected]>
+#
+# 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/>.
+
+import qubesmgmt.tests
+from qubesmgmt.label import Label
+
+
+class TC_00_Label(qubesmgmt.tests.QubesTestCase):
+    def test_000_list(self):
+        self.app.expected_calls[
+            ('dom0', 'mgmt.label.List', None, None)] = \
+            b'0\x00green\nred\nblack\n'
+        seen = set()
+        for label in self.app.labels:
+            self.assertNotIn(label.name, seen)
+            seen.add(label.name)
+        self.assertEqual(seen, set(['green', 'red', 'black']))
+
+    def test_010_get(self):
+        self.app.expected_calls[
+            ('dom0', 'mgmt.label.List', None, None)] = \
+            b'0\x00green\nred\nblack\n'
+        label = self.app.labels['green']
+        self.assertIsInstance(label, Label)
+        self.assertEqual(label.name, 'green')
+
+    def test_011_get_color(self):
+        self.app.expected_calls[
+            ('dom0', 'mgmt.label.List', None, None)] = \
+            b'0\x00green\nred\nblack\n'
+        self.app.expected_calls[
+            ('dom0', 'mgmt.label.Get', 'green', None)] = \
+            b'0\x000x00FF00'
+        label = self.app.labels['green']
+        self.assertEqual(label.color, '0x00FF00')
+