Implemented static tags on VMs

cloudcontrol/node/hypervisor/__init__.py

@@ -418,6 +418,41 @@ class Handler(HostHandler):
         # update autostart value now instead of 10 seconds lag
         vm.tag_db['__main__']['autostart'].update_value()
 
+
+    @libvirt_handler
+    def tag_add(self, name, tag, value):
+        """Add a static tag on specified VM.
+
+        :param name: VM name
+        :param tag: tag name
+        :param value: tag value
+        """
+
+        vm = self.hypervisor.domains[name]
+        vm.set_tag(tag, value)
+
+    @libvirt_handler
+    def tag_delete(self, name, tag):
+        """Delete a static tag on specified VM.
+
+        :param name: VM name
+        :param tag: tag name
+        """
+
+        vm = self.hypervisor.domains[name]
+        vm.delete_tag(tag)
+
+    @libvirt_handler
+    def tag_show(self, name):
+        """Show static tags of the specified VM.
+
+        :param name: VM name
+        """
+
+        vm = self.hypervisor.domains[name]
+        return vm.tags
+
+
     @libvirt_handler
     def vol_create(self, pool, name, size):
         logger.debug('Volume create %s, pool %s, size %s', name, pool, size)

cloudcontrol/node/hypervisor/domains/__init__.py

@@ -14,6 +14,7 @@
 # along with CloudControl.  If not, see <http://www.gnu.org/licenses/>.
 
 
+import re
 import errno
 import logging
 import socket
@@ -36,6 +37,10 @@ from cloudcontrol.node.exc import ConsoleAlreadyOpened, ConsoleError
 
 logger = logging.getLogger(__name__)
 
+REGEX_TAG_NAME = '[a-zA-Z0-9_-]+'
+REGEX_TAG_VALUE = '.+'
+REGEX_TAG_IN_DESCRIPTION = '^@(' + REGEX_TAG_NAME + ')[ ]*?=[ ]*?(' + REGEX_TAG_VALUE + ')$'
+REGEX_TAG_REPLACE = '^@%s[ ]*?=[ ]*?(' + REGEX_TAG_VALUE + ')$'
 
 NetworkInterface = namedtuple('NetworkInterface', ('source', 'mac', 'model'))
 
@@ -97,6 +102,9 @@ class VirtualMachine(object):
 
         self.redefine_on_stop = False  # for XML update (see KVM class)
 
+        self._description_tags_db = TagDB(parent_db=self.tag_db)
+        self.sync_description_tags()
+
     @property
     def state(self):
         return self._state
@@ -106,6 +114,67 @@ class VirtualMachine(object):
         self._state = value
         self.tag_db['__main__']['status'].update_value()
         self.tag_db['__main__']['vncport'].update_value()
+        self.sync_description_tags()
+
+    @property
+    def description(self):
+        descriptions = et.ElementTree().parse(StringIO(self.lv_dom.XMLDesc(0))).findall('description')
+        if descriptions:
+            return descriptions[0].text
+        else:
+            return ''
+
+    @description.setter
+    def description(self, value):
+        try:
+            xml = self.lv_dom.XMLDesc(0)
+        except libvirt.libvirtError:
+            logger.exception('Error while getting domain XML from libvirt, %s',
+                             self.name)
+            raise
+
+        xml_tree = et.ElementTree()
+        xml_tree.parse(StringIO(xml))
+        desc = xml_tree.find('description')
+        desc.text = value
+
+        # write back the XML tree
+        out = StringIO()
+        xml_tree.write(out)
+        try:
+            self.hypervisor.vir_con.defineXML(out.getvalue())
+        except libvirt.libvirtError:
+            logger.exception('Cannot update XML file for domain %s', self.name)
+            raise
+
+    @property
+    def tags(self):
+        return dict(re.findall(REGEX_TAG_IN_DESCRIPTION, self.description, re.MULTILINE))
+
+    def set_tag(self, tag, value):
+        if not re.match(REGEX_TAG_NAME + '$', tag):
+            raise RuntimeError('Bad tag name')
+        elif not re.match(REGEX_TAG_VALUE + '$', value):
+            raise RuntimeError('Bad tag value')
+
+        tags = self.tags
+
+        if tag in tags:
+            self.description = re.sub(REGEX_TAG_REPLACE % re.escape(tag),
+                                      '@%s=%s' % (tag, value),
+                                      self.description,
+                                      flags=re.MULTILINE)
+        else:
+            self.description += '\n@%s=%s' % (tag, value)
+
+    def delete_tag(self, tag):
+        tags = self.tags
+
+        if tag in tags:
+            self.description = re.sub(REGEX_TAG_REPLACE % tag,
+                                      '',
+                                      self.description,
+                                      flags=re.MULTILINE)
 
     @property
     def lv_dom(self):
@@ -119,6 +188,22 @@ class VirtualMachine(object):
 
         self.lv_dom.createWithFlags(flags)
 
+    def sync_description_tags(self):
+        tags = dict(re.findall(REGEX_TAG_IN_DESCRIPTION, self.description, re.MULTILINE))
+
+        # Add/update static tags:
+        for k, v in tags.iteritems():
+            tag = self._description_tags_db['__main__'].get(k)
+            if tag is None:
+                self._description_tags_db.add_tag(Tag(k, v, -1))
+            else:
+                tag.value = v
+
+        # Purge not more defined static tags:
+        for k in self._description_tags_db['__main__']:
+            if k not in tags:
+                self._description_tags_db.remove_tag(k)
+
     def stop(self):
         self.lv_dom.shutdown()