Fix broken create/shutdown code

IPython/nbconvert/preprocessors/execute.py

@@ -1,116 +1,115 b''
 """Module containing a preprocessor that removes the outputs from code cells"""
 
 # Copyright (c) IPython Development Team.
 # Distributed under the terms of the Modified BSD License.
 
 #-----------------------------------------------------------------------------
 # Imports
 #-----------------------------------------------------------------------------
 
 import os
 import sys
 
 from Queue import Empty
 from IPython.kernel import KernelManager
 from IPython.nbformat.current import reads, NotebookNode, writes
 
 from .base import Preprocessor
 
 
 #-----------------------------------------------------------------------------
 # Classes
 #-----------------------------------------------------------------------------
 class ExecutePreprocessor(Preprocessor):
     """
     Executes all the cells in a notebook
     """
     def __init__(self, extra_arguments=[], **kwargs):
         """
         Start an kernel to run the Python code
         """
         super(ExecutePreprocessor, self).__init__(**kwargs)
         self.extra_arguments = []
 
-    def preprocess(self, nb, resources):
+    def _create_client(self):
         self.km = KernelManager()
         self.km.start_kernel(extra_arguments=self.extra_arguments, stderr=open(os.devnull, 'w'))
         self.kc = self.km.client()
         self.kc.start_channels()
         self.iopub = self.kc.iopub_channel
         self.shell = self.kc.shell_channel
-
         self.shell.execute("pass")
         self.shell.get_msg()
 
+    def _shutdown_client(self):
+        self.kc.stop_channels()
+        self.km.shutdown_kernel()
+        del self.km
 
-        create_client()
+    def preprocess(self, nb, resources):
+        self._create_client()
         nb, resources = super(ExecutePreprocessor, self).preprocess(nb, resources)
-        shutdown_client()
+        self._shutdown_client()
         return nb, resources
 
     def preprocess_cell(self, cell, resources, cell_index):
         """
         Apply a transformation on each code cell. See base.py for details.
         """
         if cell.cell_type != 'code':
             return cell, resources
         try:
             outputs = self.run_cell(self.shell, self.iopub, cell)
         except Exception as e:
             self.log.error("failed to run cell: " + repr(e))
             self.log.error(str(cell.input))
             sys.exit(1)
         cell.outputs = outputs
         return cell, resources
 
     @staticmethod
     def run_cell(shell, iopub, cell):
         # print cell.input
         shell.execute(cell.input)
         # wait for finish, maximum 20s
         shell.get_msg(timeout=20)
         outs = []
 
         while True:
             try:
                 msg = iopub.get_msg(timeout=0.2)
             except Empty:
                 break
             msg_type = msg['msg_type']
             if msg_type in ('status', 'pyin'):
                 continue
             elif msg_type == 'clear_output':
                 outs = []
                 continue
 
             content = msg['content']
             # print msg_type, content
             out = NotebookNode(output_type=msg_type)
 
             if msg_type == 'stream':
                 out.stream = content['name']
                 out.text = content['data']
             elif msg_type in ('display_data', 'pyout'):
                 out['metadata'] = content['metadata']
                 for mime, data in content['data'].iteritems():
                     attr = mime.split('/')[-1].lower()
                     # this gets most right, but fix svg+html, plain
                     attr = attr.replace('+xml', '').replace('plain', 'text')
                     setattr(out, attr, data)
                 if msg_type == 'pyout':
                     out.prompt_number = content['execution_count']
             elif msg_type == 'pyerr':
                 out.ename = content['ename']
                 out.evalue = content['evalue']
                 out.traceback = content['traceback']
             else:
                 self.log.error("unhandled iopub msg: " + msg_type)
 
             outs.append(out)
         return outs
 
-
-    def __del__(self):
-        self.kc.stop_channels()
-        self.km.shutdown_kernel()
-        del self.km