How to make flask response to client asynchronously?

Question

Flask is a single thread web server. But I want to make it won't block when handle some time consuming request.

For example:

from flask import Flask
import time
import sys
app = Flask(__name__)

@app.route("/")
def hello():
    print "request"
    sys.stdout.flush()
    for _ in range(10000000):
        for j in range(10000000):
            i = 1
    return "Hello World!"

if __name__ == "__main__":
    app.run(debug=True)

I want when every client request to server, it always output "request" on console immediately. I have try gunicorn and run with gunicorn -k gevent -w 4 a:app but it still appears synchronous.

Answer 1

This snippet is a good starting point.

You also should look into Celery or RQ, they're the right thing to use for larger projects, more importantly they're not Flask-specific.

They also have Flask integration each, Flask-Celery and Flask-RQ.