# HG changeset patch
# User Mads Kiilerich <madski@unity3d.com>
# Date 2016-01-05 16:23:22
# Node ID d5707598fd643601b8cc4a82e00f61aba0c674ab
# Parent  2189802db18a01d15cff9650ab5dc8c31263f585

db: fix unknown exception type in commit error handling

efce61aac33d was a blind fix. It failed because `from sqlalchemy import *`
doesn't import exc and the new except clause would thus fail. It also failed
because the session has to be rolled back after a commit failure.

Now, rework it to fix these issues.

Note that we are able to detect whether the commit failed for valid reasons ...
but we can't use that information to much ...

diff --git a/kallithea/model/db.py b/kallithea/model/db.py
--- a/kallithea/model/db.py
+++ b/kallithea/model/db.py
@@ -34,6 +34,7 @@ import hashlib
 import collections
 import functools
 
+import sqlalchemy
 from sqlalchemy import *
 from sqlalchemy.ext.hybrid import hybrid_property
 from sqlalchemy.orm import relationship, joinedload, class_mapper, validates
@@ -2136,19 +2137,22 @@ class CacheInvalidation(Base, BaseModel)
             return True
 
         inv_obj = cls.query().filter(cls.cache_key == cache_key).scalar()
-        if not inv_obj:
+        if inv_obj is None:
             inv_obj = CacheInvalidation(cache_key, repo_name)
-        if inv_obj.cache_active:
+        elif inv_obj.cache_active:
             return True
         inv_obj.cache_active = True
         Session().add(inv_obj)
         try:
             Session().commit()
-        except exc.IntegrityError:
+        except sqlalchemy.exc.IntegrityError:
+            log.error('commit of CacheInvalidation failed - retrying')
+            Session().rollback()
             inv_obj = cls.query().filter(cls.cache_key == cache_key).scalar()
-            if not inv_obj:
-                raise
-            # TOCTOU - another thread added the key at the same time; no further action required
+            if inv_obj is None:
+                log.error('failed to create CacheInvalidation entry')
+                # TODO: fail badly?
+            # else: TOCTOU - another thread added the key at the same time; no further action required
         return False
 
     @classmethod