I am running a flask app using celery to offload long running process on a IIS 6.5 server and using python 2.7 The choice of the python 2.7, flask and IIS 7 server are imposed by the Company and cannot be changed.
The flask app works on IIS server (so the server set-up should be correct), except for the following.
I am struggling to find the good implementation to make flask works smoothly on the server. I searched for similar questions on the site, but none helped so far. When I am running the flask app on my pc, the application only performs as expected if I use OPTION A or OPTION B.
OPTION A:
from flask import Flask
app = Flask(__name__)
@app.route("/")
def hello():
return "Hello from FastCGI via IIS!"
if __name__ == "__main__":
app.run(threaded=True) # <--- This works
OPTION B:
If I wrap the flask app inside tornado, it works well as well:
from tornado.wsgi import WSGIContainer
from tornado.httpserver import HTTPServer
from tornado.ioloop import IOLoop
from myapp import app
http_server = HTTPServer(WSGIContainer(app))
http_server.listen(5000)
IOLoop.instance().start()
OPTION C:
However if I run the flask app only with the default parameters, then it does not work the webserver is not returning the view that should be returned after a task has been offloaded to celery.
from flask import Flask
app = Flask(__name__)
@app.route("/")
def hello():
return "Hello from FastCGI via IIS!"
if __name__ == "__main__":
app.run() # <--- Default App
Example of view working for OPTION A & B but not for OPTION C or on ISS:
Here below a stripped down example of a async task that is picked by celery. Note that I'm using Flask-Classy to generate the views, so the code is slightly different than the traditional routing in Flask.
class AnalysisView(FlaskView):
### Index page ---------------
def index(self):
return render_template('analysis.intro.html')
### Calculation process ------
def calculate(self, run_id):
t_id = task_create_id(run_id)
current_analysis = a_celery_function.apply_async(args=[x, y], task_id=t_id)
# Redirect to another view --> Not working when OPTION C or on ISS server
return redirect(url_for('AnalysisView:inprogress', run_id=run_id))
### Waiting page ---------------
def inprogress(self, run_id=run_id):
return render_template('analysis.inprogress.html')
My main problem is how can I use OPTION A (preferably, as it involves less change for me) or OPTION B to work together with IIS server? Is there a way to tell flask to run with threaded=True during the Flask() initialization or via config settings?
Thanks in advance for you help.
