avocado.utils.virt: Improve implementation.

Improve the current implementation by adding properties
to get status, names and domains. Add support functions
to start, stop, resume, suspend, shutdown, etc machines.

Clear documentation about what kind of snapshot: system checkpoint.
Signed-off-by: NRuda Moura <rmoura@redhat.com>

avocado/utils/virt.py

@@ -13,7 +13,7 @@
 # Author: Ruda Moura <rmoura@redhat.com>
 
 """
-Module to provide classes for virtualization.
+Module to provide classes for Virtual Machines.
 """
 
 import libvirt
@@ -37,14 +37,19 @@ class Hypervisor(object):
         self.uri = uri
         self.connection = None
         self.connected = False
-        self.domains = []
 
     def __str__(self):
         return "%s(%s)" % (self.__class__.__name__,
                            self.uri)
 
-    def _get_domains(self):
-        self.domains = self.connection.listAllDomains()
+    @property
+    def domains(self):
+        """
+        Property to get the list of all domains.
+
+        :return: a list of instances of :class:`libvirt.virDomain`.
+        """
+        return self.connection.listAllDomains()
 
     def connect(self):
         """
@@ -58,7 +63,6 @@ class Hypervisor(object):
                 return None
             else:
                 self.connected = True
-        self._get_domains()
         return self.connection
 
     def find_domain_by_name(self, name):
@@ -68,15 +72,15 @@ class Hypervisor(object):
         :param domain: the domain name.
         :return: an instance of :class:`libvirt.virDomain`.
         """
-        self._get_domains()
         for domain in self.domains:
             if name == domain.name():
                 return domain
         return None
 
-    def start_domain(self, xml):
+    def start_domain_with_xml(self, xml):
         """
-        Start domain.
+        Start/create domain with XML description.
+
         :param xml: the XML description.
         :return: an instance of :class:`libvirt.virDomain`.
         """
@@ -111,21 +115,91 @@ class VM(object):
                                    self.hypervisor.uri,
                                    self.domain.name())
 
+    @property
+    def is_active(self):
+        """
+        Property to check if VM is active.
+
+        :return: if VM is active.
+        :rtype: Boolean
+        """
+        return bool(self.domain.isActive())
+
+    @property
+    def name(self):
+        """
+        Property with the name of VM.
+
+        :return: the name of VM.
+        """
+        return self.domain.name()
+
+    @property
+    def state(self):
+        """
+        Property with the state of VM.
+
+        :return: current state name.
+        """
+        states = ['No state',
+                  'Running',
+                  'Blocked',
+                  'Paused',
+                  'Shutting down',
+                  'Shutoff',
+                  'Crashed']
+        return states[self.domain.info()[0]]
+
     def start(self):
         """
         Start VM.
         """
-        if self.domain.isActive():
-            return True
-        xml = self.domain.XMLDesc()
-        dom = self.hypervisor.start_domain(xml)
-        if dom:
-            self.domain = dom
-            return True
-        else:
-            return False
+        if self.is_active is False:
+            self.domain.create()
+
+    def suspend(self):
+        """
+        Suspend VM.
+        """
+        if self.is_active:
+            self.domain.suspend()
+
+    def resume(self):
+        """
+        Resume VM.
+        """
+        if self.is_active:
+            self.domain.resume()
+
+    def reboot(self):
+        """
+        Reboot VM.
+        """
+        if self.is_active:
+            self.domain.reboot()
+
+    def shutdown(self):
+        """
+        Shutdown VM.
+        """
+        if self.is_active:
+            self.domain.shutdown()
+
+    def reset(self):
+        """
+        Reset VM.
+        """
+        if self.is_active:
+            self.domain.reset()
 
-    def _create_snapshot_xml(self, name=None, description=None):
+    def stop(self):
+        """
+        Stop VM.
+        """
+        if self.is_active:
+            self.domain.destroy()
+
+    def _system_checkpoint_xml(self, name=None, description=None):
         def create_element(doc, tag, text):
             el = doc.createElement(tag)
             txt = doc.createTextNode(text)
@@ -141,11 +215,15 @@ class VM(object):
         root.appendChild(create_element(doc, 'description', description))
         return doc.toxml()
 
+    @property
+    def snapshots(self):
+        return self.domain.snapshotListNames()
+
     def create_snapshot(self, name=None):
         """
-        Create a snapshot point.
+        Creates a snapshot of kind 'system checkpoint'.
         """
-        xml = self._create_snapshot_xml(name)
+        xml = self._system_checkpoint_xml(name)
         self.snapshot = self.domain.snapshotCreateXML(xml)
         return self.snapshot