Reopen connection when commit or rollback fails, as suggested by Ben Hoyt.

Author: Cito

DBUtils/SteadyDB.py

@@ -402,12 +402,32 @@ def begin(self, *args, **kwargs):
     def commit(self):
         """Commit any pending transaction."""
         self._transaction = False
-        self._con.commit()
+        try:
+            self._con.commit()
+        except self._failures, error: # cannot commit
+            try: # try to reopen the connection
+                con = self._create()
+            except Exception:
+                pass
+            else:
+                self._close()
+                self._store(con)
+            raise error # reraise the original error
 
     def rollback(self):
         """Rollback pending transaction."""
         self._transaction = False
-        self._con.rollback()
+        try:
+            self._con.rollback()
+        except self._failures, error: # cannot rollback
+            try: # try to reopen the connection
+                con = self._create()
+            except Exception:
+                pass
+            else:
+                self._close()
+                self._store(con)
+            raise error # reraise the original error
 
     def cancel(self):
         """Cancel a long-running transaction.

DBUtils/Tests/TestSteadyDB.py

@@ -62,9 +62,13 @@ def close(self):
         self.valid = False
 
     def commit(self):
+        if not self.valid:
+            raise InternalError
         self.session.append('commit')
 
     def rollback(self):
+        if not self.valid:
+            raise InternalError
         self.session.append('rollback')
 
     def ping(self):
@@ -703,6 +707,50 @@ def test16_ResetTransaction(self):
         db.close()
         self.assertEqual(db._con.session, ['rollback'])
 
+    def test17_CommitError(self):
+        db = SteadyDBconnect(dbapi, database='ok')
+        db.begin()
+        self.assert_(not db._con.session)
+        self.assert_(db._con.valid)
+        db.commit()
+        self.assertEqual(db._con.session, ['commit'])
+        self.assert_(db._con.valid)
+        db.begin()
+        db._con.valid = False
+        con = db._con
+        self.assertRaises(InternalError, db.commit)
+        self.assert_(not db._con.session)
+        self.assert_(db._con.valid)
+        self.assert_(con is not db._con)
+        db.begin()
+        self.assert_(not db._con.session)
+        self.assert_(db._con.valid)
+        db.commit()
+        self.assertEqual(db._con.session, ['commit'])
+        self.assert_(db._con.valid)
+
+    def test18_RollbackError(self):
+        db = SteadyDBconnect(dbapi, database='ok')
+        db.begin()
+        self.assert_(not db._con.session)
+        self.assert_(db._con.valid)
+        db.rollback()
+        self.assertEqual(db._con.session, ['rollback'])
+        self.assert_(db._con.valid)
+        db.begin()
+        db._con.valid = False
+        con = db._con
+        self.assertRaises(InternalError, db.rollback)
+        self.assert_(not db._con.session)
+        self.assert_(db._con.valid)
+        self.assert_(con is not db._con)
+        db.begin()
+        self.assert_(not db._con.session)
+        self.assert_(db._con.valid)
+        db.rollback()
+        self.assertEqual(db._con.session, ['rollback'])
+        self.assert_(db._con.valid)
+
 
 if __name__ == '__main__':
     unittest.main()