Gevent学习

2024-06-18 12:39

文章标签 学习 gevent

本文主要是介绍Gevent学习，希望对大家解决编程问题提供一定的参考价值，需要的开发者们随着小编来一起学习吧！

Monkey patching

from gevent import monkey
monkey.patch_all()

在开头的地方用了patch_all，会把标准库中的thread/socket等给替换掉，变成非阻塞的了.

#!/usr/bin/env python
# -*- coding: utf-8 -*-"""#  @file       py_concurrent_download.py#  @brief---------------------------------------------------------功能简介    Spawn multiple workers and wait for them to complete---------------------------------------------------------#  @version    1.0.0#  @author     LindenTao(lindentao@qq.com)#  @date       2017/5/7 16:57
"""from __future__ import print_functionimport gevent
from gevent import monkey# patches stdlib (including socket and ssl modules) to cooperate with other greenlets
monkey.patch_all()import sysurls = ['http://www.baidu.com', 'http://www.yandex.ru', 'http://www.qq.com', 'http://www.github.com']if sys.version_info[0] == 3:from urllib.request import urlopen  # pylint:disable=import-error,no-name-in-module
else:from urllib2 import urlopen  # pylint: disable=import-errordef print_head(url):print('Starting %s' % url)data = urlopen(url).read()print('%s: %s bytes: %r' % (url, len(data), data[:50]))jobs = [gevent.spawn(print_head, _url) for _url in urls]gevent.wait(jobs)

用patch_all的结果（异步）：
这里写图片描述
不用patch_all结果（同步）：

数据结构

事件

import gevent
from gevent.event import Event'''
Illustrates the use of events
'''evt = Event()def setter():'''After 3 seconds, wake all threads waiting on the value of evt'''print('A: Hey wait for me, I have to do something')gevent.sleep(3)print("Ok, I'm done")evt.set()def waiter():'''After 3 seconds the get call will unblock'''print("I'll wait for you")evt.wait()  # blockingprint("It's about time")gevent.joinall([gevent.spawn(setter),gevent.spawn(waiter),gevent.spawn(waiter),gevent.spawn(waiter),gevent.spawn(waiter),gevent.spawn(waiter)
])

应用

简单server

#!/usr/bin/env python2.7
# -*- coding: utf-8 -*-'''
Created on 2016/08/16
File Name:py_gevent.py
author: LindenTao
Description : python gevent demo
'''# On Unix: Access with ``$ nc 127.0.0.1 5000``
# On Window: Access with ``$ telnet 127.0.0.1 5000``from gevent.server import StreamServerdef handle(socket, address):socket.send("Hello from a telnet!\n")for i in range(5):socket.send(str(i) + '\n')socket.close()server = StreamServer(('127.0.0.1', 5000), handle)
server.serve_forever()

WSGI Servers

gevent.wsgi.WSGIServer

from gevent.wsgi import WSGIServerdef application(environ, start_response):status = '200 OK'body = '<p>Hello World</p>'headers = [('Content-Type', 'text/html')]start_response(status, headers)return [body]WSGIServer(('', 8000), application).serve_forever()

gevent.pywsgi.WSGIServer

from gevent.pywsgi import WSGIServerdef application(environ, start_response):status = '200 OK'headers = [('Content-Type', 'text/html')]start_response(status, headers)yield "<p>Hello"yield "World</p>"WSGIServer(('', 8000), application).serve_forever()

Long Polling

import gevent
from gevent.queue import Queue, Empty
from gevent.pywsgi import WSGIServer
import simplejson as jsondata_source = Queue()def producer():while True:data_source.put_nowait('Hello World')gevent.sleep(1)def ajax_endpoint(environ, start_response):status = '200 OK'headers = [('Content-Type', 'application/json')]start_response(status, headers)while True:try:datum = data_source.get(timeout=5)yield json.dumps(datum) + '\n'except Empty:passgevent.spawn(producer)WSGIServer(('', 8000), ajax_endpoint).serve_forever()

Gevent ZeroMQ

#!/usr/bin/env python2.7
# -*- coding: utf-8 -*-'''
Created on 2016/08/16
File Name:py_gevent.py
author: LindenTao
Description : python gevent demo
'''# Note: Remember to ``pip install pyzmq gevent_zeromq``
import gevent
import zmq.green as zmq# Global Context
context = zmq.Context()def server():server_socket = context.socket(zmq.REQ)server_socket.bind("tcp://127.0.0.1:5000")for request in range(1, 10):server_socket.send("Hello")print('Switched to Server for %s' % request)# Implicit context switch occurs hereserver_socket.recv()def client():client_socket = context.socket(zmq.REP)client_socket.connect("tcp://127.0.0.1:5000")for request in range(1, 10):client_socket.recv()print('Switched to Client for %s' % request)# Implicit context switch occurs hereclient_socket.send("World")publisher = gevent.spawn(server)
client    = gevent.spawn(client)gevent.joinall([publisher, client])