update shared data in the background

main.py

import threading
import time
import transaction

from .models import get_tm_session

def worker(dbsession_factory, registry):
    while True:
        tm = transaction.TransactionManager(explicit=True)
        with tm:
            dbsession = get_tm_session(dbsession_factory, tm)
            
            some_objs = dbsession.query(...)
            results = serialize(some_objs)
            
            with registry['background_payload_lock']:
                registry['background_payload'] = results
            
            time.sleep(60)
            
def view(request):
    with request.registry['background_payload_lock']:
        results = request.registry['background_payload']
        
    some_objs = deserialize(results)

def main(global_config, **settings):
    config = Configurator(settings=settings)
    config.include('.models')
    
    # prepare the registry to handle background work
    config.registry['background_payload_lock'] = threading.Lock()
    config.registry['background_payload'] = {}
    
    dbsession_factory = config.registry['dbsession_factory']
    t = threading.Thread(target=worker, args=(dbsession_factory, config.registry))
    t.daemon = True
    t.start()
    
    return config.make_wsgi_app()