如何在這種情況下使用龍捲風協程？

Question

我創建了龍捲風服務器，它接受python和matlab代碼並執行它。這是服務器代碼。

from zmq.eventloop.zmqstream import ZMQStream 
from zmq.eventloop import ioloop 
ioloop.install() 

from functools import partial 
from tornado import web, gen, escape 
from tornado import options, httpserver 
from tornado.concurrent import Future 

settings = dict() 
settings['autoreload'] = True 
settings['debug'] = True 

from jupyter_client import MultiKernelManager 

reply_futures = {} 
kids = [] 

class MainHandler(web.RequestHandler): 
    def get(self): 
     self.write("Hello") 

class ExecuteHandler(web.RequestHandler): 
    def get(self): 
     self.write("approaching execute") 

    def post(self): 
     data = escape.json_decode(self.request.body) 
     print data 
     self.application.execute_code(data) 

class Application(web.Application): 

    def __init__(self): 

     handlers = [] 
     handlers.append((r"/", MainHandler)) 
     handlers.append((r"/execute", ExecuteHandler)) 
     web.Application.__init__(self, handlers, **settings) 
     self.km = MultiKernelManager() 
     self.setup_kernels() 

    def setup_kernels(self): 

     matlab_kernel_id = self.km.start_kernel(kernel_name="matlab") 
     python_kernel_id = self.km.start_kernel(kernel_name="python") 

     self.matlab_kernel_id = matlab_kernel_id 
     self.python_kernel_id = python_kernel_id 

     matkab_kernel_client = self.km.get_kernel(matlab_kernel_id).client() 
     matkab_kernel_client.start_channels() 

     python_kernel_client = self.km.get_kernel(python_kernel_id).client() 
     python_kernel_client.start_channels() 

     self.matkab_kernel_client = matkab_kernel_client 
     self.python_kernel_client = python_kernel_client 

     matlab_iopub_stream = ZMQStream(matkab_kernel_client.iopub_channel.socket) 
     matlab_shell_stream = ZMQStream(matkab_kernel_client.shell_channel.socket) 

     python_iopub_stream = ZMQStream(python_kernel_client.iopub_channel.socket) 
     python_shell_stream = ZMQStream(python_kernel_client.shell_channel.socket) 

     matlab_iopub_stream.on_recv_stream(partial(self.reply_callback, matkab_kernel_client.session)) 
     matlab_shell_stream.on_recv_stream(partial(self.reply_callback, matkab_kernel_client.session)) 

     python_iopub_stream.on_recv_stream(partial(self.reply_callback, python_kernel_client.session)) 
     python_shell_stream.on_recv_stream(partial(self.reply_callback, python_kernel_client.session)) 

    def reply_callback(self, session, stream, msg_list): 
     idents, msg_parts = session.feed_identities(msg_list) 
     reply = session.deserialize(msg_parts) 

     if "stream" == reply["msg_type"]: 
      print reply["content"]["text"] 
     parent_id = reply['parent_header'].get('msg_id') 
     reply_future = reply_futures.get(parent_id) 
     if reply_future: 
      reply_future.set_result(reply) 

    def execute_code(self, data): 

     matlab_code = data['matlab_code'] 
     python_code = data['python_code'] 

     self.execute_matlab_then_python(matlab_code, python_code) 

    @gen.coroutine 
    def execute_matlab_then_python(self, matlab_code, python_code): 

     print "executing matlab code" 
     parent_id1 = self.matkab_kernel_client.execute(matlab_code) 
     f1 = reply_futures[parent_id1] = Future() 
     yield f1  

     print "executing python code" 
     parent_id2 = self.python_kernel_client.execute(python_code) 
     f2 = reply_futures[parent_id2] = Future() 
     yield f2 

    def shutdown_kernels(self): 
     self.km.get_kernel(self.matlab_kernel_id).cleanup_connection_file() 
     self.km.shutdown_kernel(self.matlab_kernel_id) 

     self.km.get_kernel(self.python_kernel_id).cleanup_connection_file() 
     self.km.shutdown_kernel(self.python_kernel_id) 

if __name__ == '__main__': 

    options.parse_command_line() 
    app = Application() 
    server = httpserver.HTTPServer(app) 
    server.listen(8888) 

    try: 
     ioloop.IOLoop.current().start() 
    except KeyboardInterrupt: 
     print 'going down' 
    finally:  
     app.shutdown_kernels() 

我用它來訪問的客戶端代碼，這裏

import json 
import requests 

matlab_code = "a=magic(3);disp(a)" 
python_code = "print 'Hello World!!'" 

data = {} 
data['matlab_code'] = matlab_code 
data['python_code'] = python_code 

r = requests.post('http://0.0.0.0:8888/execute', json.dumps(data)) 

我關心的是保持執行的順序，以使MATLAB完成後，才Python代碼得到執行。我使用jupyter_client來執行matlab/python代碼。我在這裏使用python27。問題是，當我提交代碼時，它會拋出TypeError: 'NoneType' object is not iterable。這是一個堆棧跟蹤它。

 
[E 160809 15:17:51 ioloop:633] Exception in callback None 
    Traceback (most recent call last): 
     File "/usr/local/lib/python2.7/dist-packages/tornado/ioloop.py", line 887, in start 
     handler_func(fd_obj, events) 
     File "/usr/local/lib/python2.7/dist-packages/tornado/stack_context.py", line 275, in null_wrapper 
     return fn(*args, **kwargs) 
     File "/usr/local/lib/python2.7/dist-packages/zmq/eventloop/zmqstream.py", line 440, in _handle_events 
     self._handle_recv() 
     File "/usr/local/lib/python2.7/dist-packages/zmq/eventloop/zmqstream.py", line 472, in _handle_recv 
     self._run_callback(callback, msg) 
     File "/usr/local/lib/python2.7/dist-packages/zmq/eventloop/zmqstream.py", line 414, in _run_callback 
     callback(*args, **kwargs) 
     File "/usr/local/lib/python2.7/dist-packages/tornado/stack_context.py", line 275, in null_wrapper 
     return fn(*args, **kwargs) 
     File "/usr/local/lib/python2.7/dist-packages/zmq/eventloop/zmqstream.py", line 191, in 
     self.on_recv(lambda msg: callback(self, msg), copy=copy) 
     File "tornado_test.py", line 86, in reply_callback 
     reply_future.set_result(reply) 
     File "/usr/local/lib/python2.7/dist-packages/tornado/concurrent.py", line 276, in set_result 
     self._set_done() 
     File "/usr/local/lib/python2.7/dist-packages/tornado/concurrent.py", line 320, in _set_done 
     for cb in self._callbacks: 
    TypeError: 'NoneType' object is not iterable 

我不明白這裏有什麼問題？

Answer 1

不幸的是，神祕的錯誤消息「'NoneType'對象不可迭代」意味着您在同一個Future對象上多次呼叫set_result。我對zmq或jupyter內核接口知之甚少，但我的猜測是，兩種不同內核的execute方法返回的ID是重疊的，或者每個執行調用獲得多個響應（來自兩個不同的流？）。