sqlalchemy with no threadlocals

main.py

from pyramid.config import Configurator
from pyramid.view import view_config

def main(global_config, **app_settings):
    config = Configurator(settings=app_settings)
    config.include('.model')
    
    config.scan(__name__)
    return config.make_wsgi_app()
    
@view_config()
def dummy_view(context, request):
    # request.db.query(...)
    return request.response

model.py

from sqlalchemy import engine_from_config
from sqlalchemy.orm import sessionmaker
import zope.sqlalchemy

def includeme(config):
    settings = config.get_settings()
    dbmaker = init_model(settings)

    config.add_request_method(
        lambda r: get_dbsession(r, dbmaker),
        'dbsession',
        reify=True,
    )
    config.include('pyramid_tm')

def get_dbsession(request, dbmaker):
    dbsession = dbmaker()
    zope.sqlalchemy.register(dbsession, transaction_manager=request.tm)
    return dbsession
    
def init_model(settings, prefix='sqlalchemy.'):
    engine = engine_from_config(settings, prefix)
    dbmaker = sessionmaker()
    dbmaker.configure(bind=engine)
    return dbmaker