Gevent - SSL WSGIServer blocks when it shouldn't

Question

So I am creating a server, and making a request to it, all in the same file.

This works properly:

import gevent
import gevent.monkey
gevent.monkey.patch_all()

import requests

from gevent.pywsgi import WSGIServer
from flask import Flask


app = Flask(__name__)
app.debug = True

# Simple catch-all server
@app.route('/', defaults={'path': ''}, methods=['GET', 'POST'])
@app.route('/<path:path>', methods=['GET', 'POST'])
def catch_all(path):
    return 'It is Working!'


if __name__ == '__main__':
    http_server = WSGIServer(('', 8080), app)
    srv_greenlet = gevent.spawn(http_server.start)
    gevent.sleep(0.5)
    resp = requests.get('http://127.0.0.1:8080/')
    print resp.text
    http_server.stop()
    gevent.joinall([srv_greenlet])

Output:

(py2sni)user@host$ python question.py 
127.0.0.1 - - [2013-10-01 11:48:46] "GET / HTTP/1.1" 200 130 0.000614
It is Working!

But this blocks, and I have to kill the process externally:

import gevent
import gevent.monkey
gevent.monkey.patch_all()

import requests

from gevent.pywsgi import WSGIServer
from flask import Flask


app = Flask(__name__)
app.debug = True

# Simple catch-all server
@app.route('/', defaults={'path': ''}, methods=['GET', 'POST'])
@app.route('/<path:path>', methods=['GET', 'POST'])
def catch_all(path):
    return 'It is Working!'


if __name__ == '__main__':
    http_server = WSGIServer(('', 4430), app, keyfile='server.key', certfile='server.crt')
    srv_greenlet = gevent.spawn(http_server.start)
    gevent.sleep(0.5)
    resp = requests.get('https://127.0.0.1:4430/')
    print resp.text
    http_server.stop()
    gevent.joinall([srv_greenlet])

The only difference in these two scripts is that one uses SSL and the other does not. Where am I making a mistake here? If it helps, I am using gevent 0.13.8 and requests 2.0

Answer 1

The problem lies here.

It only occurs when using pyopenssl and gevent/greenlet. Because the retry of the handshake has no IO the control is never given to the greenlet running flask, so the handshake can never succeed.

I have opened a bugreport/pullrequest for this over at shazow/urllib3#250. It should be straightforward to backport yourself or wait for the next minor release of requests.