Created
January 24, 2012 19:52
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flask/gunicorn concurrency example
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""" | |
run with: | |
gunicorn -w 1 --worker-class gevent web | |
open in a browser: | |
localhost:8000/consumer | |
localhost:8000/consumer | |
localhost:8000/producer | |
Why is it that the consumer requests are queued such that only one is active at | |
a time while the producer request is allowed to operate concurrently with the | |
consumer request? The same behavior is exhibited if you try to run concurrent | |
producers. | |
""" | |
from gevent import monkey | |
monkey.patch_all() | |
from gevent import sleep | |
from gevent import Timeout | |
from flask import Flask | |
from flask import Response | |
from redis import Redis | |
redis = Redis() | |
app = Flask(__name__) | |
application = app # for easy gunicorn | |
chanel = "thread_channel:" + str(42) | |
@app.route('/producer', methods=['POST', 'GET']) | |
def message_post(): | |
return Response(producer(), mimetype='application/json') | |
def producer(): | |
print "producer" | |
for i in xrange(0, 100): | |
redis.publish(chanel, i) | |
yield [i] | |
sleep(.05) | |
@app.route('/consumer', methods=['GET']) | |
def thread_get(): | |
return Response(consumer(), mimetype='application/json') | |
def consumer(): | |
print "consumer" | |
pubsub = redis.pubsub() | |
try: | |
with Timeout(30) as timeout: | |
pubsub.subscribe(chanel) | |
for x in pubsub.listen(): | |
yield [x['data']] | |
except Timeout, t: | |
if t is not timeout: | |
raise # not my timeout | |
else: | |
pubsub.unsubscribe(chanel) | |
if __name__ == '__main__': | |
from gevent import pywsgi | |
hp = ('127.0.0.1', 8000) | |
server = pywsgi.WSGIServer(hp, app) | |
print "Serving on http://%s" % ":".join([str(x) for x in hp]) | |
server.serve_forever() |
Send requests with curl or anything else than browser as browser has a limit on the number of simultaneous connections per site or per address. Or use two different browsers.
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i am not sure about what the problem is.