Make sure the storage is thread safe.

Author: davidkhess

src/oidcmsg/storage/absqlalchemy.py

@@ -2,7 +2,7 @@
 import json
 
 import sqlalchemy as alchemy_db
-from sqlalchemy.orm import sessionmaker
+from sqlalchemy.orm import sessionmaker, scoped_session
 
 PlainDict = dict
 
@@ -15,7 +15,7 @@ def __init__(self, conf_dict):
                                       self.metadata, autoload=True,
                                       autoload_with=self.engine)
         Session = sessionmaker(bind=self.engine)
-        self.session = Session()
+        self.session = scoped_session(Session)
 
     def get(self, k):
         entry = self.session.query(self.table).filter_by(owner=k).first()
@@ -86,4 +86,4 @@ def flush(self):
             self.session.flush()
 
     def __setitem__(self, k, v):
-        return self.set(k, v)
+        return self.set(k, v)