1 files changed, 53 insertions, 2 deletions
diff --git a/nova/utils.py b/nova/utils.py
index 27589c30ce..6d3ddd092a 100644
--- a/nova/utils.py
+++ b/nova/utils.py
@@ -22,6 +22,7 @@ System-level utilities and helper functions.
 
 import datetime
 import inspect
+import json
 import os
 import random
 import subprocess
@@ -333,6 +334,20 @@ class LazyPluggable(object):
         return getattr(backend, key)
 
 
+class LoopingCallDone(Exception):
+    """The poll-function passed to LoopingCall can raise this exception to
+    break out of the loop normally. This is somewhat analogous to
+    StopIteration.
+
+    An optional return-value can be included as the argument to the exception;
+    this return-value will be returned by LoopingCall.wait()
+    """
+
+    def __init__(self, retvalue=True):
+        """:param retvalue: Value that LoopingCall.wait() should return"""
+        self.retvalue = retvalue
+
+
 class LoopingCall(object):
     def __init__(self, f=None, *args, **kw):
         self.args = args
@@ -351,12 +366,15 @@ class LoopingCall(object):
                 while self._running:
                     self.f(*self.args, **self.kw)
                     greenthread.sleep(interval)
+            except LoopingCallDone, e:
+                self.stop()
+                done.send(e.retvalue)
             except Exception:
                 logging.exception('in looping call')
                 done.send_exception(*sys.exc_info())
                 return
-
-            done.send(True)
+            else:
+                done.send(True)
 
         self.done = done
 
@@ -391,3 +409,36 @@ def utf8(value):
         return value.encode("utf-8")
     assert isinstance(value, str)
     return value
+
+
+def to_primitive(value):
+    if type(value) is type([]) or type(value) is type((None,)):
+        o = []
+        for v in value:
+            o.append(to_primitive(v))
+        return o
+    elif type(value) is type({}):
+        o = {}
+        for k, v in value.iteritems():
+            o[k] = to_primitive(v)
+        return o
+    elif isinstance(value, datetime.datetime):
+        return str(value)
+    elif hasattr(value, 'iteritems'):
+        return to_primitive(dict(value.iteritems()))
+    elif hasattr(value, '__iter__'):
+        return to_primitive(list(value))
+    else:
+        return value
+
+
+def dumps(value):
+    try:
+        return json.dumps(value)
+    except TypeError:
+        pass
+    return json.dumps(to_primitive(value))
+
+
+def loads(s):
+    return json.loads(s)