关于并发，异步，非阻塞(python)疑惑的一些资料解答

从iterable/iterator到generator到coroutine
理解python的迭代器: http://python.jobbole.com/81916/
理解python的生成器: http://python.jobbole.com/81911/
python中协程:http://python.jobbole.com/87156/

从yield/send到yield from/asycio到asyc/awati
Python协程从yield/send到async/await: http://python.jobbole.com/86069/
深入理解 Python 异步编程(上):http://python.jobbole.com/88291/

服务器是如何承受大量的用户请求的:https://www.zhihu.com/question/27629526
flask是如何处理多个访问请求的：https://segmentfault.com/q/1010000004532745
tornado 异步笔记:https://www.jianshu.com/p/31fae7dd05ba

tornado和flask异步的例子,请求非阻塞

#-*-coding:utf8-*-

import tornado.httpserver
import tornado.ioloop
import tornado.options
import tornado.web

import time
import os
import urllib.request
from tornado.options import define,options
define("port",default=8000,help="run on the given port",type=int)


class Async1Handler(tornado.web.RequestHandler):
    @tornado.web.asynchronous
    @tornado.gen.coroutine
    def get(self,*args,**kwargs):
        print("begin!")
        response = yield tornado.gen.Task(self.open)
        print(response)
        self.finish("it works")

    @tornado.gen.coroutine
    def open(self):
        
        return (urllib.request.urlopen('http://127.0.0.1:5000/asyn/'))
        #os.system("ping -c 5 127.0.0.1")

if __name__ == "__main__":
    tornado.options.parse_command_line()
    print("****listening 127.0.0.1:8000****")
    app = tornado.web.Application(
                handlers=[(r'/async',Async1Handler)],
                debug="True")
    http_server = tornado.httpserver.HTTPServer(app)
    http_server.listen(options.port)
    tornado.ioloop.IOLoop.instance().start()

# coding=utf-8
# Python Version: 3.5.1

# Flask
from flask import Flask, request, g
import urllib.request

import os
from gevent import monkey
from gevent.pywsgi import WSGIServer
monkey.patch_all()


import time

app = Flask(__name__)
app.config.update(DEBUG=True)

@app.route('/asyn/', methods=['GET'])
def test_asyn_one():
    print("asyn has a request!")
    #print(urllib.request.urlopen('http://127.0.0.1:8000/async1'))
    os.system("ping -c 5 127.0.0.1")
    return 'hello asyn'


if __name__ == "__main__":
    # app.run()
    http_server = WSGIServer(('', 5000), app)
    http_server.serve_forever()