Implement thread-safety

README.rst

@@ -39,6 +39,7 @@ framework:
 - Easy, smart, pythonic style.
 - Obvious, clear structure.
 - Memory efficiency.
+- Thread safety.
 - Semantic versioning.
 
 Main idea of *Dependency Injector* is to keep dependencies under control.

VERSION

@@ -1 +1 @@
-0.9.2
+0.9.3

dependency_injector/providers.py

@@ -9,6 +9,7 @@ from .utils import is_kwarg_injection
 from .utils import is_attribute_injection
 from .utils import is_method_injection
 from .utils import get_injectable_kwargs
+from .utils import GLOBAL_LOCK
 
 from .errors import Error
 
@@ -162,8 +163,9 @@ class Singleton(Provider):
 
     def _provide(self, *args, **kwargs):
         """Return provided instance."""
-        if not self._instance:
-            self._instance = self._factory(*args, **kwargs)
+        with GLOBAL_LOCK:
+            if not self._instance:
+                self._instance = self._factory(*args, **kwargs)
         return self._instance
 
     def reset(self):

dependency_injector/utils.py

@@ -1,10 +1,15 @@
 """Utils module."""
 
+import threading
+
 import six
 
 from .errors import Error
 
 
+GLOBAL_LOCK = threading.RLock()
+
+
 def is_provider(instance):
     """Check if instance is provider instance."""
     return (not isinstance(instance, six.class_types) and

docs/index.rst

@@ -39,6 +39,7 @@ framework:
 - Easy, smart, pythonic style.
 - Obvious, clear structure.
 - Memory efficiency.
+- Thread safety.
 - Semantic versioning.
 
 Main idea of *Dependency Injector* is to keep dependencies under control.

docs/main/changelog.rst

@@ -13,6 +13,10 @@ Development version
 
 - No featues.
 
+0.9.3
+-----
+- Implement thread-safety.
+
 0.9.2
 -----
 - Add minor refactorings.

docs/providers/index.rst

@@ -12,6 +12,9 @@ Current documentation section consists from description of standard providers
 library and some useful information like overriding of providers and writing 
 custom providers.
 
+All providers are validated in multithreading environment and considered to 
+be thread-safe.
+
 ..  toctree::
     :maxdepth: 2