cyclades: Add SnapshotInstance RAPI method

Extend Ganeti RAPI client with 'SnapshotInstane' method.

snf-cyclades-app/synnefo/logic/backend.py

@@ -1051,6 +1051,13 @@ def detach_volume(vm, volume):
         return client.ModifyInstance(**kwargs)
 
 
+def snapshot_instance(vm, snapshot_name):
+    #volume = instance.volumes.all()[0]
+    with pooled_rapi_client(vm) as client:
+        return client.SnapshotInstance(instance=vm.backend_vm_id,
+                                       snapshot_name=snapshot_name)
+
+
 def get_instances(backend, bulk=True):
     with pooled_rapi_client(backend) as c:
         return c.GetInstances(bulk=bulk)

snf-cyclades-app/synnefo/logic/rapi.py

@@ -546,6 +546,30 @@ class GanetiRapiClient(object): # pylint: disable=R0904
                              ("/%s/instances/%s/deactivate-disks" %
                               (GANETI_RAPI_VERSION, instance)), None, None)
 
+  def SnapshotInstance(self, instance, snapshot_name, dry_run=False):
+    """Replaces disks on an instance.
+
+    @type instance: str
+    @param instance: instance whose disks to replace
+    @type snapshot_name: str
+    @param snapshot_name: name of the new snapshot
+
+    @rtype: string
+    @return: job id
+
+    """
+
+    body = {
+      "disks": [(0, {"snapshot_name": snapshot_name})],
+      }
+
+    query = []
+    _AppendDryRunIf(query, dry_run)
+
+    return self._SendRequest(HTTP_PUT,
+                             ("/%s/instances/%s/snapshot" %
+                              (GANETI_RAPI_VERSION, instance)), query, body)
+
   def RecreateInstanceDisks(self, instance, disks=None, nodes=None):
     """Recreate an instance's disks.