Hello,
I developed a little "prize question game" in Pyramid. I used the url
dispatch/sqlalchemy scaffold to get started. Sqlite is being used for
persistence.
In my models I defined a "Person" class (for participants) with a unique
constraint on the email attribute/field. After some time when the
application is running (and people are participating), I get these errors
(usually in the same order):
1) <class 'sqlalchemy.exc.IntegrityError'>: (IntegrityError) column email
is not unique ...
2) <class 'transaction.interfaces.TransactionFailedError'>: An operation
previously failed, with traceback: ...
3) <class 'sqlalchemy.exc.OperationalError'>: (OperationalError) database
is locked u'INSERT INTO persons...'
Finally:
4) <class 'sqlalchemy.exc.InvalidRequestError'>: This Session's
transaction has been rolled back due to a previous exception during flush.
To begin a new transaction with this Session, first issue
Session.rollback(). Original exception was: (OperationalError) database is
locked u'INSERT INTO persons ...'
After that I only get the same 'sqlalchemy.exc.InvalidRequestError' over
and over again. At that moment, the application is still running but only
shows an "Internal Server Error" to the user.
The code responsible for persisting the participant is shown below:
--------------------------
# Search person
person = DBSession.query(Person).filter(Person.email ==
sess['person']['email']).first()
if person is None:
person = Person()
sess['person']['creation_time'] = datetime.now()
else:
person.modification_time = datetime.now()
for k, v in sess['person'].iteritems():
setattr(person, k, v)
# Merge and add to db
with transaction.manager:
p = DBSession.merge(person)
DBSession.add(p)
--------------------------
As you can see, I always only wrap the write/update database interactions
in "with transaction.manager:". Could that be the problem? Should all
database interaction be wrapped in "with transaction.manager:"? Or am I
missing the point here?
Also, I have defined my views as methods of a class GameViews(object). Much
of the errors originate from this line of code "game_data =
DBSession.query(Game).filter(Game.name == game).first()" within the
"game_exists" method.
--------------------------
class GameViews(object):
"""
GameViews class
"""
def __init__(self, request):
self.request = request
self.game_data = self.get_game_data()
def get_game_data(self):
# fetch request information
game = self.request.matchdict['game']
# fetch game information from db
return DBSession.query(Game).filter(Game.name == game).first()
def game_exists(info, request):
game = request.matchdict['game']
game_data = DBSession.query(Game).filter(Game.name == game).first()
if game_data:
return True
else:
return False
--------------------------
"game_exists" is being used as a custom predicate as such:
@view_config(route_name='start', renderer='templates/01_start.pt',
custom_predicates=(game_exists))
Would this suffice as information for solving this issue?
Thanks in advance!
Maarten
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