sweep: DIRACGrid#7666 Replace __del__ with weakref.finalize in DictCache

src/DIRAC/Core/Utilities/DictCache.py

@@ -3,6 +3,7 @@
 """
 import datetime
 import threading
+import weakref
 
 # DIRAC
 from DIRAC.Core.Utilities.LockRing import LockRing
@@ -63,6 +64,9 @@ def __init__(self, deleteFunction=False, threadLocal=False):
         # Function to clean the elements
         self.__deleteFunction = deleteFunction
 
+        # Called when this object is deleted or the program ends
+        self.__finalizer = weakref.finalize(self, _purgeAll, None, self.__cache, self.__deleteFunction)
+
     @property
     def lock(self):
         """Return the lock.
@@ -221,31 +225,26 @@ def purgeExpired(self, expiredInSeconds=0):
 
     def purgeAll(self, useLock=True):
         """Purge all entries
-        CAUTION: useLock parameter should ALWAYS be True except when called from __del__
+        CAUTION: useLock parameter should ALWAYS be True
 
         :param bool useLock: use lock
         """
-        if useLock:
-            self.lock.acquire()
-        try:
-            for cKey in list(self.__cache):
-                if self.__deleteFunction:
-                    self.__deleteFunction(self.__cache[cKey]["value"])
-                del self.__cache[cKey]
-        finally:
-            if useLock:
-                self.lock.release()
-
-    def __del__(self):
-        """When the DictCache is deleted, all the entries should be purged.
-        This is particularly useful when the DictCache manages files
-        CAUTION: if you carefully read the python doc, you will see all the
-        caveat of __del__. In particular, no guaranty that it is called...
-        (https://docs.python.org/2/reference/datamodel.html#object.__del__)
-        """
-        self.purgeAll(useLock=False)
-        del self.__lock
-        if self.__threadLocal:
-            del self.__threadLocalCache
-        else:
-            del self.__sharedCache
+        _purgeAll(self.lock if useLock else None, self.__cache, self.__deleteFunction)
+
+
+def _purgeAll(lock, cache, deleteFunction):
+    """Purge all entries
+
+    This is split in to a helper function to be used by the finalizer without
+    needing to add a reference to the DictCache object itself.
+    """
+    if lock:
+        lock.acquire()
+    try:
+        for cKey in list(cache):
+            if deleteFunction:
+                deleteFunction(cache[cKey]["value"])
+            del cache[cKey]
+    finally:
+        if lock:
+            lock.release()

src/DIRAC/FrameworkSystem/Client/ProxyManagerClient.py

@@ -32,7 +32,8 @@ def __init__(self):
         self.__pilotProxiesCache = DictCache()
         self.__filesCache = DictCache(self.__deleteTemporalFile)
 
-    def __deleteTemporalFile(self, filename):
+    @staticmethod
+    def __deleteTemporalFile(filename):
         """Delete temporal file
 
         :param str filename: path to file