mongodb - APScheduler run async function in Tornado Python -

i trying develop small app gather weather data api. have used apscheduler execute function every x minutes. use python tornado framework.

the error getting is:

info     job "getweather (trigger: interval[0:01:00], next run at: 2015-03-28 11:40:58 cet)" executed error    exception in callback functools.partial(<function wrap.<locals>.null_wrapper @ 0x0335c978>, <tornado.concurrent.future object @ 0x03374430>) traceback (most recent call last):   file "c:\python34\lib\site-packages\tornado\ioloop.py", line 568, in _run_callback     ret = callback()   file "c:\python34\lib\site-packages\tornado\stack_context.py", line 275, in null_wrapper     return fn(*args, **kwargs) greenlet.error: cannot switch different thread 

which think coming coroutine getweather() as, if remove asycn features it, works.

i using motor read needed coordinates , pass them through api , store weather data in mongodb.

import os.path, logging import tornado.web import tornado.ioloop tornado.httpclient import asynchttpclient tornado import gen tornado.options import define, options apscheduler.schedulers.tornado import tornadoscheduler import motor  client = motor.motorclient() db = client['apitest']  console_log = logging.getlogger(__name__)  define("port", default=8888, help="run on given port", type=int) define("debug", default=false, help="run in debug mode")  class mainrequest (tornado.web.requesthandler):     def get(self):         self.write("hello")  scheduler = tornadoscheduler()  class scheduledtasks(object):     def get(self):         print("this scheduler");  def addjobs():     scheduler.add_job(getweather, 'interval', minutes=1)  def startscheduler():     scheduler.start();  def stopscheduler():     scheduler.stop();  class weather(tornado.web.requesthandler):     def get(self):         self.write("this weather robot!")         getweather()  @gen.coroutine def getweather():     '''     getting city weather forecast.io api     '''     console_log.debug('start: weather robot')         cursor = findcities()      while (yield cursor.fetch_next):         city = cursor.next_object()         lat = str(city["lat"])         lon = str(city["lon"])              http_client = asynchttpclient()         response = yield http_client.fetch("https://api.forecast.io/forecast/3925d0668cf520768ca855951f1097cd/%s,%s" %(lat, lon))          if response.error:             print ("error:", response.error)             # store cities errors in order save them in log file         else:                      json = tornado.escape.json_decode(response.body)             temperature =  json["currently"]["temperature"]             summary = json["currently"]["summary"]             db.cities.update({'_id': city["_id"]}, {'$set': {'temperature': temperature, 'summary': summary}})      console_log.debug('end: weather robot')     return  def findcities():     '''     cities = [{                 "_id" : objectid("55165d07258058ee8dca2172"),                 "name" : "london",                 "country" : "united kingdom",                 "lat" : 51.507351,                 "lon" : -0.127758             },             {                 "_id" : objectid("55165d07258058ee8dca2173"),                 "name" : "barcelona",                 "country" : "spain",                 "lat" : 41.385064,                 "lon" : 2.173403             }           '''     cities = db.cities.find().sort([('_id', -1)])     return cities  def main():     logging.basicconfig(level=logging.debug,format='%(levelname)-8s %(message)s')     app = tornado.web.application(             [                 (r'/robots/weather', weather),                 (r'/', mainrequest)             ],             cookie_secret="__todo:_generate_your_own_random_value_here__",             login_url="/auth/login",             template_path=os.path.join(os.path.dirname(__file__), "templates"),             static_path=os.path.join(os.path.dirname(__file__), "static"),             xsrf_cookies=true,             debug=options.debug,         )     app.listen(options.port)     addjobs()     startscheduler()     tornado.ioloop.ioloop.instance().start()   if __name__ == "__main__":     main() 

any idea doing wrong? see in apscheduler code, tornadoscheduler() runs in tornado ioloop... (https://bitbucket.org/agronholm/apscheduler/src/a34075b0037dba46735bae67f598ec6133003ef1/apscheduler/schedulers/tornado.py?at=master)

oh! forgot idea able execute task via apscheduler or manually both.

many thanks!

by default, tornadoscheduler runs scheduled tasks in thread pool. specific task, however, uses ioloop , expects run in same thread. fix this, can use add_callback() method of tornado ioloop schedule task run in ioloop's thread possible.

like so:

def your_scheduled_task():     ioloop.instance().add_callback(your_real_task_function) 

or better:

scheduler.add_job(ioloop.instance().add_callback, 'interval', minutes=1, args=[getweather])