Merge pull request #29 from gutenbergtools/fix_ramsession

improved ramsession patch

sessions.py

@@ -1,5 +1,5 @@
 # will submit a PR to CherryPy project - if it gets merged we can remove it. ESH 8/15/2019
-
+import cherrypy
 from cherrypy.lib.sessions import RamSession as cpRamSession
 
 class RamSession(cpRamSession):
@@ -8,7 +8,17 @@ class RamSession(cpRamSession):
 
         now = self.now()
         try:
-            for _id, (data, expiration_time) in list(self.cache.items()):
+            cache_items_copy = self.cache.copy().items()
+        except RuntimeError as re:
+            """Under heavy load, list(self.cache.items()) will occasionally raise this error
+            for large session caches with message "dictionary changed size during iteration"
+            Better to pause the cleanup than to let the cleanup thread die.
+            """
+            cherrypy.log(f'Runtime Error happened while copying the cache entries: {re}')
+            cherrypy.log('Ref: https://github.com/cherrypy/cherrypy/pull/1804')
+            return
+
+        for _id, (data, expiration_time) in cache_items_copy:
             if expiration_time <= now:
                 try:
                     del self.cache[_id]
@@ -21,11 +31,6 @@ class RamSession(cpRamSession):
                 except KeyError:
                     pass
 
-        except RuntimeError:
-            """Under heavy load, list(self.cache.items()) will occasionally raise this error
-            for large session caches with message "dictionary changed size during iteration"
-            Better to pause the cleanup than to let the cleanup thread die.
-            """
 
             return