TypeError: an integer is required, SQLAlchemy + Flask

Question

I've got the following code which runs on my machine without errors:

def update_user():
    user = User.query.get(session.get('user') or -1)
    if user is None:
        return
    if not user.token_valid():
        session.pop('user', None)
        return
    user.lastlogin_time = int(time.time())
    user.lastlogin_ip = request.remote_addr
    db.session.commit()

However, when I deploy it to Linux VDS (Archlinux, same version of everything) I get the following error:

Traceback (most recent call last):
  File "/usr/lib/python2.7/site-packages/flask/app.py", line 1836, in __call__
    return self.wsgi_app(environ, start_response)
  File "/usr/lib/python2.7/site-packages/flask/app.py", line 1820, in wsgi_app
    response = self.make_response(self.handle_exception(e))
  File "/usr/lib/python2.7/site-packages/flask/app.py", line 1403, in handle_exception
    reraise(exc_type, exc_value, tb)
  File "/usr/lib/python2.7/site-packages/flask/app.py", line 1817, in wsgi_app
    response = self.full_dispatch_request()
  File "/usr/lib/python2.7/site-packages/flask/app.py", line 1477, in full_dispatch_request
    rv = self.handle_user_exception(e)
  File "/usr/lib/python2.7/site-packages/flask/app.py", line 1381, in handle_user_exception
    reraise(exc_type, exc_value, tb)
  File "/usr/lib/python2.7/site-packages/flask/app.py", line 1475, in full_dispatch_request
    rv = self.dispatch_request()
  File "/usr/lib/python2.7/site-packages/flask/app.py", line 1461, in dispatch_request
    return self.view_functions[rule.endpoint](**req.view_args)
  File "/home/asn007/backends/rust.q-b.eu/app/views.py", line 32, in main
    utils.update_user()
  File "/home/asn007/backends/rust.q-b.eu/app/utils.py", line 14, in update_user
    user = User.query.get(session.get('user') or -1)
  File "/usr/lib/python2.7/site-packages/sqlalchemy/orm/query.py", line 820, in get
    return loading.load_on_ident(self, key)
  File "/usr/lib/python2.7/site-packages/sqlalchemy/orm/loading.py", line 226, in load_on_ident
    return q.one()
  File "/usr/lib/python2.7/site-packages/sqlalchemy/orm/query.py", line 2310, in one
    ret = list(self)
  File "/usr/lib/python2.7/site-packages/sqlalchemy/orm/loading.py", line 72, in instances
    rows = [process[0](row, None) for row in fetch]
  File "/usr/lib/python2.7/site-packages/sqlalchemy/orm/loading.py", line 447, in _instance
    populate_state(state, dict_, row, isnew, only_load_props)
  File "/usr/lib/python2.7/site-packages/sqlalchemy/orm/loading.py", line 301, in populate_state
    populator(state, dict_, row)
  File "/usr/lib/python2.7/site-packages/sqlalchemy/orm/strategies.py", line 151, in fetch_col
    dict_[key] = row[col]
TypeError: an integer is required

My model source code:

class User(db.Model):
    __tablename__ = 'users'
    uid = db.Column(db.Integer, autoincrement=True)
    vk_id = db.Column(db.BigInteger, primary_key=True, unique=True)
    vk_token = db.Column(db.Text)
    vk_token_expiration = db.Column(db.BigInteger)
    name = db.Column(db.Text)
    email = db.Column(db.Text)
    is_banned = db.Column(db.Boolean)
    lastvote = db.Column(db.Integer)
    lastlogin_time = db.Column(db.BigInteger)
    lastlogin_ip = db.Column(db.String(255))
    api_key = db.Column(db.String(128))

    def __init__(self, uid=None, vk_id=None, vk_token=None, vk_token_expiration=None, email=None, name=None,
                 is_banned=False, lastvote=None, lastlogin_time=None, lastlogin_ip=None, api_key=None):
        super(User, self).__init__()
        self.uid = uid
        self.vk_id = vk_id
        self.vk_token = vk_token
        self.vk_token_expiration = vk_token_expiration
        self.name = name
        self.email = email
        self.is_banned = is_banned
        self.lastvote = lastvote
        self.lastlogin_time = lastlogin_time
        self.lastlogin_ip = lastlogin_ip
        self.api_key = api_key

    def token_valid(self):
        return self.vk_token_expiration > int(time.time())

    def can_create_projects(self):
        return len(Project.query.filter_by(owner=self.uid).all()) < 10

    def can_vote(self):
        return self.lastvote + 60 * 60 * 24 <= int(time.time())

UPD1 : forgot to mention that session['user'] is definitely an integer

Answer 1

It could be that one of your columns in that user's row is a different type than SQLAlchemy expects.

Here is an example of someone getting that error because one of their Boolean columns was empty instead of true or false: https://groups.google.com/forum/#!topic/sqlalchemy/SrKN8yfYEUw