"""A kernel manager for multiple kernels."""
#-----------------------------------------------------------------------------
# Copyright (C) 2011 The IPython Development Team
#
# Distributed under the terms of the BSD License. The full license is in
# the file COPYING.txt, distributed as part of this software.
#-----------------------------------------------------------------------------
#-----------------------------------------------------------------------------
# Imports
#-----------------------------------------------------------------------------
import signal
import sys
import uuid
import zmq
from tornado import web
from .routers import IOPubStreamRouter, ShellStreamRouter
from IPython.config.configurable import LoggingConfigurable
from IPython.zmq.ipkernel import launch_kernel
from IPython.utils.traitlets import Instance, Dict, List, Unicode
#-----------------------------------------------------------------------------
# Classes
#-----------------------------------------------------------------------------
class DuplicateKernelError(Exception):
pass
class KernelManager(LoggingConfigurable):
"""A class for managing multiple kernels."""
context = Instance('zmq.Context')
def _context_default(self):
return zmq.Context.instance()
_kernels = Dict()
@property
def kernel_ids(self):
"""Return a list of the kernel ids of the active kernels."""
return self._kernels.keys()
def __len__(self):
"""Return the number of running kernels."""
return len(self.kernel_ids)
def __contains__(self, kernel_id):
if kernel_id in self.kernel_ids:
return True
else:
return False
def start_kernel(self, **kwargs):
"""Start a new kernel."""
kernel_id = unicode(uuid.uuid4())
(process, shell_port, iopub_port, stdin_port, hb_port) = launch_kernel(**kwargs)
# Store the information for contacting the kernel. This assumes the kernel is
# running on localhost.
d = dict(
process = process,
stdin_port = stdin_port,
iopub_port = iopub_port,
shell_port = shell_port,
hb_port = hb_port,
ip = '127.0.0.1'
)
self._kernels[kernel_id] = d
return kernel_id
def kill_kernel(self, kernel_id):
"""Kill a kernel by its kernel uuid.
Parameters
==========
kernel_id : uuid
The id of the kernel to kill.
"""
kernel_process = self.get_kernel_process(kernel_id)
if kernel_process is not None:
# Attempt to kill the kernel.
try:
kernel_process.kill()
except OSError, e:
# In Windows, we will get an Access Denied error if the process
# has already terminated. Ignore it.
if not (sys.platform == 'win32' and e.winerror == 5):
raise
del self._kernels[kernel_id]
def interrupt_kernel(self, kernel_id):
"""Interrupt (SIGINT) the kernel by its uuid.
Parameters
==========
kernel_id : uuid
The id of the kernel to interrupt.
"""
kernel_process = self.get_kernel_process(kernel_id)
if kernel_process is not None:
if sys.platform == 'win32':
from parentpoller import ParentPollerWindows as Poller
Poller.send_interrupt(kernel_process.win32_interrupt_event)
else:
kernel_process.send_signal(signal.SIGINT)
def signal_kernel(self, kernel_id, signum):
""" Sends a signal to the kernel by its uuid.
Note that since only SIGTERM is supported on Windows, this function
is only useful on Unix systems.
Parameters
==========
kernel_id : uuid
The id of the kernel to signal.
"""
kernel_process = self.get_kernel_process(kernel_id)
if kernel_process is not None:
kernel_process.send_signal(signum)
def get_kernel_process(self, kernel_id):
"""Get the process object for a kernel by its uuid.
Parameters
==========
kernel_id : uuid
The id of the kernel.
"""
d = self._kernels.get(kernel_id)
if d is not None:
return d['process']
else:
raise KeyError("Kernel with id not found: %s" % kernel_id)
def get_kernel_ports(self, kernel_id):
"""Return a dictionary of ports for a kernel.
Parameters
==========
kernel_id : uuid
The id of the kernel.
Returns
=======
port_dict : dict
A dict of key, value pairs where the keys are the names
(stdin_port,iopub_port,shell_port) and the values are the
integer port numbers for those channels.
"""
d = self._kernels.get(kernel_id)
if d is not None:
dcopy = d.copy()
dcopy.pop('process')
dcopy.pop('ip')
return dcopy
else:
raise KeyError("Kernel with id not found: %s" % kernel_id)
def get_kernel_ip(self, kernel_id):
"""Return ip address for a kernel.
Parameters
==========
kernel_id : uuid
The id of the kernel.
Returns
=======
ip : str
The ip address of the kernel.
"""
d = self._kernels.get(kernel_id)
if d is not None:
return d['ip']
else:
raise KeyError("Kernel with id not found: %s" % kernel_id)
def create_session_manager(self, kernel_id):
"""Create a new session manager for a kernel by its uuid."""
from sessionmanager import SessionManager
return SessionManager(
kernel_id=kernel_id, kernel_manager=self,
config=self.config, context=self.context, log=self.log
)
class RoutingKernelManager(LoggingConfigurable):
"""A KernelManager that handles WebSocket routing and HTTP error handling"""
kernel_argv = List(Unicode)
kernel_manager = Instance(KernelManager)
_routers = Dict()
_session_dict = Dict()
_notebook_mapping = Dict()
#-------------------------------------------------------------------------
# Methods for managing kernels and sessions
#-------------------------------------------------------------------------
@property
def kernel_ids(self):
"""List the kernel ids."""
return self.kernel_manager.kernel_ids
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."""
notebook_ids = [k for k, v in self._notebook_mapping.iteritems() if v == kernel_id]
if len(notebook_ids) == 1:
return notebook_ids[0]
else:
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 start_kernel(self, notebook_id=None):
"""Start a kernel 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.
"""
self.log.info
kernel_id = self.kernel_for_notebook(notebook_id)
if kernel_id is None:
kwargs = dict()
kwargs['extra_arguments'] = self.kernel_argv
kernel_id = self.kernel_manager.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)
self.start_session_manager(kernel_id)
else:
self.log.info("Using existing kernel: %s" % kernel_id)
return kernel_id
def start_session_manager(self, kernel_id):
"""Start the ZMQ sockets (a "session") to connect to a kernel."""
sm = self.kernel_manager.create_session_manager(kernel_id)
self._session_dict[kernel_id] = sm
iopub_stream = sm.get_iopub_stream()
shell_stream = sm.get_shell_stream()
iopub_router = IOPubStreamRouter(
zmq_stream=iopub_stream, session=sm.session, config=self.config
)
shell_router = ShellStreamRouter(
zmq_stream=shell_stream, session=sm.session, config=self.config
)
self.set_router(kernel_id, 'iopub', iopub_router)
self.set_router(kernel_id, 'shell', shell_router)
def kill_kernel(self, kernel_id):
"""Kill a kernel and remove its notebook association."""
if kernel_id not in self.kernel_manager:
raise web.HTTPError(404)
try:
sm = self._session_dict.pop(kernel_id)
except KeyError:
raise web.HTTPError(404)
sm.stop()
self.kernel_manager.kill_kernel(kernel_id)
self.delete_mapping_for_kernel(kernel_id)
self.log.info("Kernel killed: %s" % kernel_id)
def interrupt_kernel(self, kernel_id):
"""Interrupt a kernel."""
if kernel_id not in self.kernel_manager:
raise web.HTTPError(404)
self.kernel_manager.interrupt_kernel(kernel_id)
self.log.debug("Kernel interrupted: %s" % kernel_id)
def restart_kernel(self, kernel_id):
"""Restart a kernel while keeping clients connected."""
if kernel_id not in self.kernel_manager:
raise web.HTTPError(404)
# Get the notebook_id to preserve the kernel/notebook association
notebook_id = self.notebook_for_kernel(kernel_id)
# Create the new kernel first so we can move the clients over.
new_kernel_id = self.start_kernel()
# Copy the clients over to the new routers.
old_iopub_router = self.get_router(kernel_id, 'iopub')
old_shell_router = self.get_router(kernel_id, 'shell')
new_iopub_router = self.get_router(new_kernel_id, 'iopub')
new_shell_router = self.get_router(new_kernel_id, 'shell')
new_iopub_router.copy_clients(old_iopub_router)
new_shell_router.copy_clients(old_shell_router)
# Shut down the old routers
old_shell_router.close()
old_iopub_router.close()
self.delete_router(kernel_id, 'shell')
self.delete_router(kernel_id, 'iopub')
del old_shell_router
del old_iopub_router
# Now shutdown the old session and the kernel.
# TODO: This causes a hard crash in ZMQStream.close, which sets
# self.socket to None to hastily. We will need to fix this in PyZMQ
# itself. For now, we just leave the old kernel running :(
# Maybe this is fixed now, but nothing was changed really.
self.kill_kernel(kernel_id)
# Now save the new kernel/notebook association. We have to save it
# after the old kernel is killed as that will delete the mapping.
self.set_kernel_for_notebook(notebook_id, new_kernel_id)
self.log.debug("Kernel restarted: %s" % new_kernel_id)
return new_kernel_id
def get_router(self, kernel_id, stream_name):
"""Return the router for a given kernel_id and stream name."""
router = self._routers[(kernel_id, stream_name)]
return router
def set_router(self, kernel_id, stream_name, router):
"""Set the router for a given kernel_id and stream_name."""
self._routers[(kernel_id, stream_name)] = router
def delete_router(self, kernel_id, stream_name):
"""Delete a router for a kernel_id and stream_name."""
try:
del self._routers[(kernel_id, stream_name)]
except KeyError:
pass