meinheld 0.3.2

High performance asynchronous Python WSGI Web Server

What’s this

this is a python wsgi web server.

Thus this is yet an another asynchronous web server like fapws3, tornado.

And meinheld is a WSGI compliant web server.

Require

meinheld requires Python 2.x >= 2.5. and greenlet >= 0.3.1.

sorry meinheld supported linux only.

Installation

Install from pypi:

$ easy_install -ZU meinheld

Install from source:

$ python setup.py install

meinheld support gunicorn .

To install gunicorn:

$ easy_install -ZU gunicorn

Basic Usage

simple wsgi app:

from meinheld import server

def hello_world(environ, start_response):
    status = '200 OK'
    res = "Hello world!"
    response_headers = [('Content-type','text/plain'),('Content-Length',str(len(res)))]
    start_response(status, response_headers)
    return [res]

server.listen(("0.0.0.0", 8000))
server.run(hello_world)

with gunicorn. user worker class “egg:meinheld#gunicorn_worker” or “meinheld.gmeinheld.MeinheldWorker”:

$ gunicorn --workers=2 --worker-class="egg:meinheld#gunicorn_worker" gunicorn_test:app

Continuation

meinheld provide simple continuation API (based on greenlet).

to enable continuation, use SpawnMiddleware. get Continuation from wsgi environ.

Continuation Object has couple method, suspend and resume.

example

from meinheld import server
from meinheld import middleware

def app(environ, start_response):
    ...

    #get Continuation
    c = environ.get(middleware.CONTINUATION_KEY, None)

    ...

    if condtion:
        waiters.append(c)
        #suspend
        c.suspend()
    else:
        for c in waiters:
            # resume suspend function
            c.resume()

    ...


server.listen(("0.0.0.0", 8000))
server.run(middleware.SpawnMiddleware(hello_world))

For more info see http://github.com/mopemope/meinheld/tree/master/example/chat/

Websocket

meinheld support Websocket. use WebSocketMiddleware.

example

from flask import Flask, render_template, request
from meinheld import server, middleware

SECRET_KEY = 'development key'
DEBUG=True

app = Flask(__name__)
app.config.from_object(__name__)


participants = set()


@app.route('/')
def index():
    return render_template('websocket_chat.html')

@app.route('/chat')
def chat():
    print request.environ
    ws = request.environ.get('wsgi.websocket')
    participants.add(ws)
    try:
        while True:
            print "ws.wait()..."
            m = ws.wait()
            print "recv msg %s" % m
            if m is None:
                break
            for p in participants:
                print "send message %s" % m
                p.send(m)
    finally:
        participants.remove(ws)
    return ""


if __name__ == "__main__":
    server.listen(("0.0.0.0", 8000))
    server.run(middleware.WebSocketMiddleware(app))

Performance

meinheld is used high performance http_parser.

(see http://github.com/ry/http-parser)

and useing high performance event library picoev.

(see http://developer.cybozu.co.jp/kazuho/2009/08/picoev-a-tiny-e.html)

simple benchmark result here

sendfile

meinheld use sendfile(2), over wgsi.file_wrapper.