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Provide a more useful error for invalid use case....
Provide a more useful error for invalid use case. The previous help statement was not very usefull for users who don't know how to use nbconvert (ironically, the exact set of users who would encounter the error).

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kernelmanager.py
110 lines | 4.1 KiB | text/x-python | PythonLexer
"""A kernel manager relating notebooks and kernels
Authors:
* Brian Granger
"""
#-----------------------------------------------------------------------------
# Copyright (C) 2013 The IPython Development Team
#
# Distributed under the terms of the BSD License. The full license is in
# the file COPYING, distributed as part of this software.
#-----------------------------------------------------------------------------
#-----------------------------------------------------------------------------
# Imports
#-----------------------------------------------------------------------------
from tornado import web
from IPython.kernel.multikernelmanager import MultiKernelManager
from IPython.utils.traitlets import (
Dict, List, Unicode,
)
#-----------------------------------------------------------------------------
# Classes
#-----------------------------------------------------------------------------
class MappingKernelManager(MultiKernelManager):
"""A KernelManager that handles notebook mapping and HTTP error handling"""
def _kernel_manager_class_default(self):
return "IPython.kernel.ioloop.IOLoopKernelManager"
kernel_argv = List(Unicode)
_notebook_mapping = Dict()
#-------------------------------------------------------------------------
# Methods for managing kernels and sessions
#-------------------------------------------------------------------------
def kernel_for_notebook(self, notebook_id):
"""Return the kernel_id for a notebook_id or None."""
return self._notebook_mapping.get(notebook_id)
def set_kernel_for_notebook(self, notebook_id, kernel_id):
"""Associate a notebook with a kernel."""
if notebook_id is not None:
self._notebook_mapping[notebook_id] = kernel_id
def notebook_for_kernel(self, kernel_id):
"""Return the notebook_id for a kernel_id or None."""
for notebook_id, kid in self._notebook_mapping.iteritems():
if kernel_id == kid:
return notebook_id
return None
def delete_mapping_for_kernel(self, kernel_id):
"""Remove the kernel/notebook mapping for kernel_id."""
notebook_id = self.notebook_for_kernel(kernel_id)
if notebook_id is not None:
del self._notebook_mapping[notebook_id]
def _handle_kernel_died(self, kernel_id):
"""notice that a kernel died"""
self.log.warn("Kernel %s died, removing from map.", kernel_id)
self.delete_mapping_for_kernel(kernel_id)
self.remove_kernel(kernel_id)
def start_kernel(self, notebook_id=None, **kwargs):
"""Start a kernel for a notebook an return its kernel_id.
Parameters
----------
notebook_id : uuid
The uuid of the notebook to associate the new kernel with. If this
is not None, this kernel will be persistent whenever the notebook
requests a kernel.
"""
kernel_id = self.kernel_for_notebook(notebook_id)
if kernel_id is None:
kwargs['extra_arguments'] = self.kernel_argv
kernel_id = super(MappingKernelManager, self).start_kernel(**kwargs)
self.set_kernel_for_notebook(notebook_id, kernel_id)
self.log.info("Kernel started: %s" % kernel_id)
self.log.debug("Kernel args: %r" % kwargs)
# register callback for failed auto-restart
self.add_restart_callback(kernel_id,
lambda : self._handle_kernel_died(kernel_id),
'dead',
)
else:
self.log.info("Using existing kernel: %s" % kernel_id)
return kernel_id
def shutdown_kernel(self, kernel_id, now=False):
"""Shutdown a kernel by kernel_id"""
super(MappingKernelManager, self).shutdown_kernel(kernel_id, now=now)
self.delete_mapping_for_kernel(kernel_id)
# override _check_kernel_id to raise 404 instead of KeyError
def _check_kernel_id(self, kernel_id):
"""Check a that a kernel_id exists and raise 404 if not."""
if kernel_id not in self:
raise web.HTTPError(404, u'Kernel does not exist: %s' % kernel_id)