RAPI: implement instance reinstall

This patch adds instance reinstall to RAPI, with two optional parameters:
  - ‘os', in order to change the OS on reinstall
  - ‘nostartup’, in order to leave the instance down after reinstall

The call will first shutdown the instance, the reinstall it, and unless
‘nostartup’ has been passed and is equal to 1, it will be started
automatically.

Signed-off-by: Iustin Pop <iustin@google.com>
Reviewed-by: Guido Trotter <ultrotter@google.com>

lib/rapi/baserlib.py

@@ -252,6 +252,18 @@ class R_Generic(object):
                                 " '%s' parameter" % (name,))
     return val
 
+  def _checkStringVariable(self, name, default=None):
+    """Return the parsed value of an int argument.
+
+    """
+    val = self.queryargs.get(name, default)
+    if isinstance(val, list):
+      if val:
+        val = val[0]
+      else:
+        val = default
+    return val
+
   def getBodyParameter(self, name, *args):
     """Check and return the value for a given parameter.
 

lib/rapi/connector.py

@@ -163,6 +163,8 @@ CONNECTOR.update({
   re.compile(r'^/2/instances/([\w\._-]+)/tags$'): rlib2.R_2_instances_name_tags,
   re.compile(r'^/2/instances/([\w\._-]+)/reboot$'):
       rlib2.R_2_instances_name_reboot,
+  re.compile(r'^/2/instances/([\w\._-]+)/reinstall$'):
+      rlib2.R_2_instances_name_reinstall,
   re.compile(r'^/2/instances/([\w\._-]+)/shutdown$'):
       rlib2.R_2_instances_name_shutdown,
   re.compile(r'^/2/instances/([\w\._-]+)/startup$'):

lib/rapi/rlib2.py

@@ -493,6 +493,36 @@ class R_2_instances_name_shutdown(baserlib.R_Generic):
     return baserlib.SubmitJob([op])
 
 
+class R_2_instances_name_reinstall(baserlib.R_Generic):
+  """/2/instances/[instance_name]/reinstall resource.
+
+  Implements an instance reinstall.
+
+  """
+
+  DOC_URI = "/2/instances/[instance_name]/reinstall"
+
+  def POST(self):
+    """Reinstall an instance.
+
+    The URI takes os=name and nostartup=[0|1] optional
+    parameters. By default, the instance will be started
+    automatically.
+
+    """
+    instance_name = self.items[0]
+    ostype = self._checkStringVariable('os')
+    nostartup = self._checkIntVariable('nostartup')
+    ops = [
+      opcodes.OpShutdownInstance(instance_name=instance_name),
+      opcodes.OpReinstallInstance(instance_name=instance_name, os_type=ostype),
+      ]
+    if not nostartup:
+      ops.append(opcodes.OpStartupInstance(instance_name=instance_name,
+                                           force=False))
+    return baserlib.SubmitJob(ops)
+
+
 class _R_Tags(baserlib.R_Generic):
   """ Quasiclass for tagging resources