Add functions for manipulating VM tags

Adds tags to schema (v3), to VM definition, adds function to modify
tags, adds function to get tags, and adds tags to VM data output.

Tags will enable more granular classification of VMs based either on
administrator configuration or from automated system events.

daemon-common/common.py

@@ -306,6 +306,14 @@ def getDomainDiskList(zkhandler, dom_uuid):
     return disk_list
 
 
+#
+# Get a list of domain tags
+#
+def getDomainTags(zkhandler, dom_uuid):
+    tags = zkhandler.read(('domain.meta.tags', dom_uuid)).split(',')
+    return tags
+
+
 #
 # Get domain information from XML
 #
@@ -352,6 +360,8 @@ def getInformationFromXML(zkhandler, uuid):
     else:
         stats_data = {}
 
+    domain_tags = getDomainTags(zkhandler, uuid)
+
     domain_uuid, domain_name, domain_description, domain_memory, domain_vcpu, domain_vcputopo = getDomainMainDetails(parsed_xml)
     domain_networks = getDomainNetworks(parsed_xml, stats_data)
 
@@ -378,6 +388,7 @@ def getInformationFromXML(zkhandler, uuid):
         'node_selector': domain_node_selector,
         'node_autostart': bool(strtobool(domain_node_autostart)),
         'migration_method': domain_migration_method,
+        'tags': domain_tags,
         'description': domain_description,
         'profile': domain_profile,
         'memory': int(domain_memory),

daemon-common/vm.py

@@ -174,7 +174,7 @@ def flush_locks(zkhandler, domain):
     return success, message
 
 
-def define_vm(zkhandler, config_data, target_node, node_limit, node_selector, node_autostart, migration_method=None, profile=None, initial_state='stop'):
+def define_vm(zkhandler, config_data, target_node, node_limit, node_selector, node_autostart, migration_method=None, profile=None, tags=[], initial_state='stop'):
     # Parse the XML data
     try:
         parsed_xml = lxml.objectify.fromstring(config_data)
@@ -246,6 +246,7 @@ def define_vm(zkhandler, config_data, target_node, node_limit, node_selector, no
         (('domain.meta.migrate_method', dom_uuid), migration_method),
         (('domain.meta.node_limit', dom_uuid), formatted_node_limit),
         (('domain.meta.node_selector', dom_uuid), node_selector),
+        (('domain.meta.tags', dom_uuid), ','.join(tags)),
         (('domain.migrate.sync_lock', dom_uuid), ''),
     ])
 
@@ -282,6 +283,35 @@ def modify_vm_metadata(zkhandler, domain, node_limit, node_selector, node_autost
     return True, 'Successfully modified PVC metadata of VM "{}".'.format(domain)
 
 
+def modify_vm_tags(zkhandler, domain, action, tags):
+    dom_uuid = getDomainUUID(zkhandler, domain)
+    if not dom_uuid:
+        return False, 'ERROR: Could not find VM "{}" in the cluster!'.format(domain)
+
+    if action in ['replace']:
+        zkhandler.write([
+            (('domain.meta.tags', dom_uuid), ','.join(tags))
+        ])
+    elif action in ['add']:
+        current_tags = zkhandler.read(('domain.meta.tags', dom_uuid)).split(',')
+        updated_tags = current_tags + tags
+        zkhandler.write([
+            (('domain.meta.tags', dom_uuid), ','.join(updated_tags))
+        ])
+    elif action in ['remove']:
+        current_tags = zkhandler.read(('domain.meta.tags', dom_uuid)).split(',')
+        for tag in tags:
+            if tag in current_tags:
+                current_tags.remove(tag)
+        zkhandler.write([
+            (('domain.meta.tags', dom_uuid), ','.join(current_tags))
+        ])
+    else:
+        return False, 'Specified tag action is not available.'
+
+    return True, 'Successfully modified tags of VM "{}".'.format(domain)
+
+
 def modify_vm(zkhandler, domain, restart, new_vm_config):
     dom_uuid = getDomainUUID(zkhandler, domain)
     if not dom_uuid:

daemon-common/zkhandler.py

@@ -466,7 +466,7 @@ class ZKHandler(object):
 #
 class ZKSchema(object):
     # Current version
-    _version = 2
+    _version = 3
 
     # Root for doing nested keys
     _schema_root = ''
@@ -576,6 +576,7 @@ class ZKSchema(object):
             'meta.migrate_method': '/migration_method',
             'meta.node_selector': '/node_selector',
             'meta.node_limit': '/node_limit',
+            'meta.tags': '/tags',
             'migrate.sync_lock': '/migrate_sync_lock'
         },
         # The schema of an individual network entry (/networks/{vni})