How to setup nginx + tornado + flask?

Question

These are my fully working tornado and flask files:

Tornado:

from flaskk import app
from tornado.wsgi import WSGIContainer
from tornado.ioloop import IOLoop
from tornado.web import FallbackHandler, RequestHandler, Application

class MainHandler(RequestHandler):
  def get(self):
    self.write("This message comes from Tornado ^_^")

tr = WSGIContainer(app)

application = Application([
    (r"/tornado", MainHandler),
    (r".*", FallbackHandler, dict(fallback=tr)),
])

if __name__ == '__main__':
    application.listen(5052)
    IOLoop.instance().start()

Flask:

from flask import Flask, jsonify
from flask_restful import Resource, Api

app = Flask(__name__)
api = Api(app)

class Report(Resource):
    def get(self):
        return 'hello from flask'

api.add_resource(Report, '/report')

Now I'm trying to setup nginx in front of tornado.
My nginx config file is:

worker_processes 3;

error_log  logs/error.;

events {
    worker_connections 1024;
}

http {
    # Enumerate all the Tornado servers here
    upstream frontends {
        server 127.0.0.1:5052;
    }

    include mime.types;
    default_type application/octet-stream;

    keepalive_timeout 65;

    sendfile on;


    server {
        listen 5050;
        server_name  localhost;

        location / {
            proxy_pass_header Server;
            proxy_set_header Host $http_host;
            proxy_redirect off;
            proxy_set_header X-Real-IP $remote_addr;
            proxy_set_header X-Scheme $scheme;
            proxy_pass http://localhost:5050;
        }
    }
}

When I do a

localhost:5050/

then I get the nginx welcome page. But when I do

localhost:5050/report

then I get a 404. Tornado is running on port 5052.
Why is nginx not calling tornado which thereby should get the result from flask?

Am I missing something here?

Answer 1

Firstly, you don't want to proxy to localhost:5050 because that is Nginx itself

You want to proxy to upstream frontends.

proxy_pass http://frontends;

---

Regarding your Flask issues, I've gotten this to work fine.

@app.route('/report')
def report():
    return 'hello from flask'

$ curl localhost:5052/report
hello from flask

When I added in Flask Restful, that still worked.

---

You said you see the index page of nginx, so it is running, you just need to correctly hook the other ports together.

The proxy_pass fix seemed to work for me.

$ curl localhost:5050/report
"hello from flask"
$ curl localhost:5050/tornado
This message comes from Tornado ^_^