[library/python/func] Made lazy and lazy_property thread safe

1 files changed, 17 insertions, 5 deletions

diff --git a/library/python/func/__init__.py b/library/python/func/__init__.py
index 7424361635..12a280bddc 100644
--- a/library/python/func/__init__.py
+++ b/library/python/func/__init__.py
@@ -20,14 +20,20 @@ class _Result(object):
 def lazy(func):
     result = _Result()
 
+    lock = threading.Lock()
+
     @functools.wraps(func)
     def wrapper(*args):
         try:
             return result.result
         except AttributeError:
-            result.result = func(*args)
+            with lock:
+                try:
+                    return result.result
+                except AttributeError:
+                    result.result = func(*args)
 
-        return result.result
+            return result.result
 
     return wrapper
 
@@ -35,11 +41,17 @@ def lazy(func):
 def lazy_property(fn):
     attr_name = '_lazy_' + fn.__name__
 
+    lock = threading.Lock()
+
     @property
     def _lazy_property(self):
-        if not hasattr(self, attr_name):
-            setattr(self, attr_name, fn(self))
-        return getattr(self, attr_name)
+        if hasattr(self, attr_name):
+            return getattr(self, attr_name)
+
+        with lock:
+            if not hasattr(self, attr_name):
+                setattr(self, attr_name, fn(self))
+            return getattr(self, attr_name)
 
     return _lazy_property