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Tornado-non-blocking-process

Tornado-non-blocking-process

作者: 单行道 | 来源:发表于2013-12-29 14:23 被阅读0次

    <pre>

    !/usr/bin/python

    import os
    import tornado.ioloop
    import tornado.web
    import tornado.gen
    import subprocess
    import fcntl

    class MainHandler(tornado.web.RequestHandler):
    """ main handler """

    def get(self):
        self.write("hello world, you requested me")
    

    class MyHandler(tornado.web.RequestHandler):
    """ my handler """

    @tornado.web.asynchronous
    def get(self):
        self.alldata = ""
        self.data = ""
        self.jobdone = 0
        self.sub("date && echo '<br/>' && echo 'start to sleep 5<br/>' && \
                    sleep 5 && echo 'sleep again<br/>' && sleep 5 && echo done")
    
    def done(self):
        ## callback is called when
        print "in done .... this is a callbck"
        print self.data
        self.write(self.data)
        self.flush()
        #self.finish()
        if self.jobdone == 1:
            self.finish()
    
    
    
    def sub(self, cmd):
    
        p = subprocess.Popen(cmd, shell=True, stdout=subprocess.PIPE)
        pout = p.stdout
        self.process = p
        fd = pout.fileno()
        fl = fcntl.fcntl(fd, fcntl.F_GETFL)
        fcntl.fcntl(fd, fcntl.F_SETFL, fl | os.O_NONBLOCK)
        ioloop = tornado.ioloop.IOLoop.instance()
        self.ioloop = ioloop
        ioloop.add_handler(fd, self.__finish_handle, ioloop.READ)
    
    def __finish_handle(self, fd, events):
        print "envent is ....  ",events
    
        ### this callback must be added everytime the event is called
        ### this callback is used for next event
        self.ioloop.add_callback(self.done)
        if self.process.poll() is not None:
            self.ioloop.remove_handler(fd)
        self.data = ""
        while True:
            try:
                data = os.read(self.process.stdout.fileno(), 10)
                # when the fd is closed
                if len(data)==0:
                    print "job is done done"
                    self.jobdone = 1
                    break
                else:
                    self.alldata += data
                    self.data += data
                    print "getdata    " + data
            except:
                break
    

    app = tornado.web.Application([
    (r'/', MainHandler),
    (r'/my', MyHandler),
    ])

    if name == 'main':
    app.listen(8080)
    tornado.ioloop.IOLoop.instance().start()

    </pre>

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