requests.get to localhost is timing out

Question

I'm trying to do http request from one handler to another but it is timing out. Why? Using request library works but not with 127.0.0.1

# sample.py
import falcon
import json
import requests

class TS:
    def on_get(self, req, resp):
        output = {
            'output': 'DataService.',
            'author': 'Python3'
        }
        resp2 = requests.get('http://127.0.0.1:8000/a')
        resp.body = json.dumps(output)
        resp.status = falcon.HTTP_200

class SE:
    def on_get(self, req, resp):
        output = {
            'output': 'Service.',
            'author': 'Python3'
        }

        resp.body = json.dumps(output)

api = falcon.API()
api.add_route('/a', SE())
api.add_route('/t', TS())

I get this error log

[2017-02-02 20:41:05 +0100] [27515] [CRITICAL] WORKER TIMEOUT (pid:27544)

Answer 1

You're probably running this using gunicorn from the command line as shown in the tutorial:

$ gunicorn sample:api

That means that gunicorn is started with the default of one worker process which is a sync worker with one thread.

This setup can only handle one request at a time, any further request will block until the previous has completed. So if you try to make a request from within your application to the same server you'll have a deadlock.

For this to work you can increase the number of worker processes and threads, e.g:

$ gunicorn --workers 2 --threads 4 sample:api