121 lines
4.0 KiB
Python
121 lines
4.0 KiB
Python
|
"""A basic kernel monitor with autorestarting.
|
||
|
|
|
||
|
|
This watches a kernel's state using KernelManager.is_alive and auto
|
||
|
|
restarts the kernel if it dies.
|
||
|
|
|
||
|
|
It is an incomplete base class, and must be subclassed.
|
||
|
|
"""
|
||
|
|
|
||
|
|
# Copyright (c) Jupyter Development Team.
|
||
|
|
# Distributed under the terms of the Modified BSD License.
|
||
|
|
|
||
|
|
from traitlets.config.configurable import LoggingConfigurable
|
||
|
|
from traitlets import (
|
||
|
|
Instance, Float, Dict, Bool, Integer,
|
||
|
|
)
|
||
|
|
|
||
|
|
|
||
|
|
class KernelRestarter(LoggingConfigurable):
|
||
|
|
"""Monitor and autorestart a kernel."""
|
||
|
|
|
||
|
|
kernel_manager = Instance('jupyter_client.KernelManager')
|
||
|
|
|
||
|
|
debug = Bool(False, config=True,
|
||
|
|
help="""Whether to include every poll event in debugging output.
|
||
|
|
|
||
|
|
Has to be set explicitly, because there will be *a lot* of output.
|
||
|
|
"""
|
||
|
|
)
|
||
|
|
|
||
|
|
time_to_dead = Float(3.0, config=True,
|
||
|
|
help="""Kernel heartbeat interval in seconds."""
|
||
|
|
)
|
||
|
|
|
||
|
|
restart_limit = Integer(5, config=True,
|
||
|
|
help="""The number of consecutive autorestarts before the kernel is presumed dead."""
|
||
|
|
)
|
||
|
|
|
||
|
|
random_ports_until_alive = Bool(True, config=True,
|
||
|
|
help="""Whether to choose new random ports when restarting before the kernel is alive."""
|
||
|
|
)
|
||
|
|
_restarting = Bool(False)
|
||
|
|
_restart_count = Integer(0)
|
||
|
|
_initial_startup = Bool(True)
|
||
|
|
|
||
|
|
callbacks = Dict()
|
||
|
|
def _callbacks_default(self):
|
||
|
|
return dict(restart=[], dead=[])
|
||
|
|
|
||
|
|
def start(self):
|
||
|
|
"""Start the polling of the kernel."""
|
||
|
|
raise NotImplementedError("Must be implemented in a subclass")
|
||
|
|
|
||
|
|
def stop(self):
|
||
|
|
"""Stop the kernel polling."""
|
||
|
|
raise NotImplementedError("Must be implemented in a subclass")
|
||
|
|
|
||
|
|
def add_callback(self, f, event='restart'):
|
||
|
|
"""register a callback to fire on a particular event
|
||
|
|
|
||
|
|
Possible values for event:
|
||
|
|
|
||
|
|
'restart' (default): kernel has died, and will be restarted.
|
||
|
|
'dead': restart has failed, kernel will be left dead.
|
||
|
|
|
||
|
|
"""
|
||
|
|
self.callbacks[event].append(f)
|
||
|
|
|
||
|
|
def remove_callback(self, f, event='restart'):
|
||
|
|
"""unregister a callback to fire on a particular event
|
||
|
|
|
||
|
|
Possible values for event:
|
||
|
|
|
||
|
|
'restart' (default): kernel has died, and will be restarted.
|
||
|
|
'dead': restart has failed, kernel will be left dead.
|
||
|
|
|
||
|
|
"""
|
||
|
|
try:
|
||
|
|
self.callbacks[event].remove(f)
|
||
|
|
except ValueError:
|
||
|
|
pass
|
||
|
|
|
||
|
|
def _fire_callbacks(self, event):
|
||
|
|
"""fire our callbacks for a particular event"""
|
||
|
|
for callback in self.callbacks[event]:
|
||
|
|
try:
|
||
|
|
callback()
|
||
|
|
except Exception as e:
|
||
|
|
self.log.error("KernelRestarter: %s callback %r failed", event, callback, exc_info=True)
|
||
|
|
|
||
|
|
def poll(self):
|
||
|
|
if self.debug:
|
||
|
|
self.log.debug('Polling kernel...')
|
||
|
|
if not self.kernel_manager.is_alive():
|
||
|
|
if self._restarting:
|
||
|
|
self._restart_count += 1
|
||
|
|
else:
|
||
|
|
self._restart_count = 1
|
||
|
|
|
||
|
|
if self._restart_count >= self.restart_limit:
|
||
|
|
self.log.warning("KernelRestarter: restart failed")
|
||
|
|
self._fire_callbacks('dead')
|
||
|
|
self._restarting = False
|
||
|
|
self._restart_count = 0
|
||
|
|
self.stop()
|
||
|
|
else:
|
||
|
|
newports = self.random_ports_until_alive and self._initial_startup
|
||
|
|
self.log.info('KernelRestarter: restarting kernel (%i/%i), %s random ports',
|
||
|
|
self._restart_count,
|
||
|
|
self.restart_limit,
|
||
|
|
'new' if newports else 'keep'
|
||
|
|
)
|
||
|
|
self._fire_callbacks('restart')
|
||
|
|
self.kernel_manager.restart_kernel(now=True, newports=newports)
|
||
|
|
self._restarting = True
|
||
|
|
else:
|
||
|
|
if self._initial_startup:
|
||
|
|
self._initial_startup = False
|
||
|
|
if self._restarting:
|
||
|
|
self.log.debug("KernelRestarter: restart apparently succeeded")
|
||
|
|
self._restarting = False
|