python - 运行多个 Tornado 进程

Question

我阅读了有关如何运行 N 个 Tornado 进程的各种文章和教程，其中 N = 核心数。我的代码可以正常运行，在所有 16 个内核上运行，但我以某种方式搞砸了，我需要重新审视它。

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

from core import settings
from core import coreService
import services

from tornado.options import define, options, parse_command_line

define("port", default=settings.SERVER_PORT, help="run on the given port", type=int)



app = tornado.web.Application([
    (r'/upload', coreService.Upload)
])

if __name__ == "__main__":
    tornado.options.parse_command_line()
    server = tornado.httpserver.HTTPServer(app, max_buffer_size=1024*1024*201)
    server.bind(options.port)
    # autodetect cpu cores and fork one process per core
    server.start(0)
    try:        
        print 'running on port %s' % options.port
        tornado.ioloop.IOLoop.instance().start()

    except KeyboardInterrupt:
        tornado.ioloop.IOLoop.instance().stop()

此代码抛出此错误:

File "/opt/tornado/tornado/process.py", line 112, in fork_processes
    raise RuntimeError("Cannot run in multiple processes: IOLoop instance "
RuntimeError: Cannot run in multiple processes: IOLoop instance has already been initialized. You cannot call IOLoop.instance() before calling start_processes()

我只是没有看到它。谢谢

:编辑:

正如本所说，我的方法之一就是给我找麻烦。这是该方法的代码，有人可能会从中受益:

from tornado import gen
import motor

db = motor.MotorClient().open_sync().proba
class Upload(BaseHandler):
    @gen.engine
    def post(self):
        fs = yield motor.Op(motor.MotorGridFS(db).open)

        gridin = yield motor.Op(fs.new_file)
        yield motor.Op(gridin.write, 'First part\n')
        yield motor.Op(gridin.write, 'Second part')
        yield motor.Op(gridin.close)

        print gridin._id
        self.write(str(gridin._id))
        self.finish()

编辑 2

我找到了问题的最终解决方案。正如本所指出的，上面的方法给我带来了麻烦。在 Motor 文档中记录了将 Motor 包含在 Tornado 应用程序中的正确方法。这是一个对我有用的异常(exception):

if __name__ == "__main__":
    tornado.options.parse_command_line()        
    try:
        server = tornado.httpserver.HTTPServer(app, max_buffer_size=1024*1024*201)
        server.bind(8888)
        server.start(0) # autodetect cpu cores and fork one process per core
        db = motor.MotorClient().open_sync().proba
        print 'running on port %s' % options.port
        # Delayed initialization of settings
        app.settings['db'] = db # from this point on db is available as self.settings['db']
        tornado.ioloop.IOLoop.instance().start()

    except KeyboardInterrupt:
        tornado.ioloop.IOLoop.instance().stop()

Answer 1

此异常在 tornado.web.Application 的 Debug模式下引发。

application = tornado.web.Application([
    (r"/", hello),
],
debug=False)

将 debug 设置为 False 以解决此问题。

您可以启动多个进程来监听每个端口:

server = tornado.httpserver.HTTPServer(application)
server.bind(1234)  # port
server.start(4) 
tornado.ioloop.IOLoop.instance().start()