Add @once decorator instead of custom hackery in breadcrumbs

2 files changed, 27 insertions, 13 deletions

diff --git a/raven/breadcrumbs.py b/raven/breadcrumbs.py
index 1d8b152..c8b1331 100644
--- a/raven/breadcrumbs.py
+++ b/raven/breadcrumbs.py
@@ -1,13 +1,9 @@
 import time
 import logging
-from threading import Lock
 from types import FunctionType
 
 from raven._compat import iteritems, get_code, text_type
-
-
-_logging_lock = Lock()
-_logging_hooked = False
+from raven.utils import once
 
 
 class BreadcrumbBuffer(object):
@@ -149,15 +145,12 @@ def _patch_logger():
         logging.Logger.log)
 
 
+@once
 def install_logging_hook():
-    global _logging_hooked
-    if _logging_hooked:
-        return
-    with _logging_lock:
-        if _logging_hooked:
-            return
-        _patch_logger()
-        _logging_hooked = True
+    """Installs the logging hook if it was not installed yet.  Otherwise
+    does nothing.
+    """
+    _patch_logger()
 
 
 import raven.context
diff --git a/raven/utils/__init__.py b/raven/utils/__init__.py
index 63f1b81..c22f0bc 100644
--- a/raven/utils/__init__.py
+++ b/raven/utils/__init__.py
@@ -9,6 +9,8 @@ from __future__ import absolute_import
 
 from raven._compat import iteritems, string_types
 import logging
+import threading
+from functools import update_wrapper
 try:
     import pkg_resources
 except ImportError:
@@ -167,3 +169,22 @@ class memoize(object):
         if n not in d:
             d[n] = self.func(obj)
         return d[n]
+
+
+def once(func):
+    """Runs a thing once and once only."""
+    lock = threading.Lock()
+
+    def new_func(*args, **kwargs):
+        if new_func.called:
+            return
+        with lock:
+            if new_func.called:
+                return
+            rv = func(*args, **kwargs)
+            new_func.called = True
+            return rv
+
+    new_func = update_wrapper(new_func, func)
+    new_func.called = False
+    return new_func