"""Base class to manage a running kernel""" #----------------------------------------------------------------------------- # 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 __future__ import absolute_import # Standard library imports import re import signal import sys import time import warnings import zmq # Local imports from IPython.config.configurable import LoggingConfigurable from IPython.utils.importstring import import_item from IPython.utils.localinterfaces import is_local_ip, local_ips from IPython.utils.traitlets import ( Any, Instance, Unicode, List, Bool, Type, DottedObjectName ) from IPython.kernel import ( make_ipkernel_cmd, launch_kernel, kernelspec, ) from .connect import ConnectionFileMixin from .zmq.session import Session from .managerabc import ( KernelManagerABC ) #----------------------------------------------------------------------------- # Main kernel manager class #----------------------------------------------------------------------------- class KernelManager(LoggingConfigurable, ConnectionFileMixin): """Manages a single kernel in a subprocess on this host. This version starts kernels with Popen. """ # The PyZMQ Context to use for communication with the kernel. context = Instance(zmq.Context) def _context_default(self): return zmq.Context.instance() # The Session to use for communication with the kernel. session = Instance(Session) def _session_default(self): return Session(parent=self) # the class to create with our `client` method client_class = DottedObjectName('IPython.kernel.blocking.BlockingKernelClient') client_factory = Type() def _client_class_changed(self, name, old, new): self.client_factory = import_item(str(new)) # The kernel process with which the KernelManager is communicating. # generally a Popen instance kernel = Any() kernel_name = Unicode('python') kernel_spec = Instance(kernelspec.KernelSpec) def _kernel_spec_default(self): return kernelspec.get_kernel_spec(self.kernel_name) def _kernel_name_changed(self, name, old, new): self.kernel_spec = kernelspec.get_kernel_spec(new) self.ipython_kernel = new in {'python', 'python2', 'python3'} kernel_cmd = List(Unicode, config=True, help="""DEPRECATED: Use kernel_name instead. The Popen Command to launch the kernel. Override this if you have a custom kernel. If kernel_cmd is specified in a configuration file, IPython does not pass any arguments to the kernel, because it cannot make any assumptions about the arguments that the kernel understands. In particular, this means that the kernel does not receive the option --debug if it given on the IPython command line. """ ) def _kernel_cmd_changed(self, name, old, new): warnings.warn("Setting kernel_cmd is deprecated, use kernel_spec to " "start different kernels.") self.ipython_kernel = False ipython_kernel = Bool(True) # Protected traits _launch_args = Any() _control_socket = Any() _restarter = Any() autorestart = Bool(False, config=True, help="""Should we autorestart the kernel if it dies.""" ) def __del__(self): self._close_control_socket() self.cleanup_connection_file() #-------------------------------------------------------------------------- # Kernel restarter #-------------------------------------------------------------------------- def start_restarter(self): pass def stop_restarter(self): pass def add_restart_callback(self, callback, event='restart'): """register a callback to be called when a kernel is restarted""" if self._restarter is None: return self._restarter.add_callback(callback, event) def remove_restart_callback(self, callback, event='restart'): """unregister a callback to be called when a kernel is restarted""" if self._restarter is None: return self._restarter.remove_callback(callback, event) #-------------------------------------------------------------------------- # create a Client connected to our Kernel #-------------------------------------------------------------------------- def client(self, **kwargs): """Create a client configured to connect to our kernel""" if self.client_factory is None: self.client_factory = import_item(self.client_class) kw = {} kw.update(self.get_connection_info()) kw.update(dict( connection_file=self.connection_file, session=self.session, parent=self, )) # add kwargs last, for manual overrides kw.update(kwargs) return self.client_factory(**kw) #-------------------------------------------------------------------------- # Kernel management #-------------------------------------------------------------------------- def format_kernel_cmd(self, **kw): """replace templated args (e.g. {connection_file})""" if self.kernel_cmd: cmd = self.kernel_cmd elif self.kernel_name == 'python': # The native kernel gets special handling cmd = make_ipkernel_cmd( 'from IPython.kernel.zmq.kernelapp import main; main()', **kw ) else: cmd = self.kernel_spec.argv ns = dict(connection_file=self.connection_file) ns.update(self._launch_args) pat = re.compile(r'\{([A-Za-z0-9_]+)\}') def from_ns(match): """Get the key out of ns if it's there, otherwise no change.""" return ns.get(match.group(1), match.group()) return [ pat.sub(from_ns, arg) for arg in cmd ] def _launch_kernel(self, kernel_cmd, **kw): """actually launch the kernel override in a subclass to launch kernel subprocesses differently """ return launch_kernel(kernel_cmd, **kw) # Control socket used for polite kernel shutdown def _connect_control_socket(self): if self._control_socket is None: self._control_socket = self.connect_control() self._control_socket.linger = 100 def _close_control_socket(self): if self._control_socket is None: return self._control_socket.close() self._control_socket = None def start_kernel(self, **kw): """Starts a kernel on this host in a separate process. If random ports (port=0) are being used, this method must be called before the channels are created. Parameters ---------- **kw : optional keyword arguments that are passed down to build the kernel_cmd and launching the kernel (e.g. Popen kwargs). """ if self.transport == 'tcp' and not is_local_ip(self.ip): raise RuntimeError("Can only launch a kernel on a local interface. " "Make sure that the '*_address' attributes are " "configured properly. " "Currently valid addresses are: %s" % local_ips() ) # write connection file / get default ports self.write_connection_file() # save kwargs for use in restart self._launch_args = kw.copy() # build the Popen cmd kernel_cmd = self.format_kernel_cmd(**kw) # launch the kernel subprocess self.kernel = self._launch_kernel(kernel_cmd, ipython_kernel=self.ipython_kernel, **kw) self.start_restarter() self._connect_control_socket() def _send_shutdown_request(self, restart=False): """TODO: send a shutdown request via control channel""" content = dict(restart=restart) msg = self.session.msg("shutdown_request", content=content) self.session.send(self._control_socket, msg) def shutdown_kernel(self, now=False, restart=False): """Attempts to the stop the kernel process cleanly. This attempts to shutdown the kernels cleanly by: 1. Sending it a shutdown message over the shell channel. 2. If that fails, the kernel is shutdown forcibly by sending it a signal. Parameters ---------- now : bool Should the kernel be forcible killed *now*. This skips the first, nice shutdown attempt. restart: bool Will this kernel be restarted after it is shutdown. When this is True, connection files will not be cleaned up. """ # Stop monitoring for restarting while we shutdown. self.stop_restarter() # FIXME: Shutdown does not work on Windows due to ZMQ errors! if now or sys.platform == 'win32': if self.has_kernel: self._kill_kernel() else: # Don't send any additional kernel kill messages immediately, to give # the kernel a chance to properly execute shutdown actions. Wait for at # most 1s, checking every 0.1s. self._send_shutdown_request(restart=restart) for i in range(10): if self.is_alive(): time.sleep(0.1) else: break else: # OK, we've waited long enough. if self.has_kernel: self._kill_kernel() if not restart: self.cleanup_connection_file() self.cleanup_ipc_files() else: self.cleanup_ipc_files() self._close_control_socket() def restart_kernel(self, now=False, **kw): """Restarts a kernel with the arguments that were used to launch it. If the old kernel was launched with random ports, the same ports will be used for the new kernel. The same connection file is used again. Parameters ---------- now : bool, optional If True, the kernel is forcefully restarted *immediately*, without having a chance to do any cleanup action. Otherwise the kernel is given 1s to clean up before a forceful restart is issued. In all cases the kernel is restarted, the only difference is whether it is given a chance to perform a clean shutdown or not. **kw : optional Any options specified here will overwrite those used to launch the kernel. """ if self._launch_args is None: raise RuntimeError("Cannot restart the kernel. " "No previous call to 'start_kernel'.") else: # Stop currently running kernel. self.shutdown_kernel(now=now, restart=True) # Start new kernel. self._launch_args.update(kw) self.start_kernel(**self._launch_args) # FIXME: Messages get dropped in Windows due to probable ZMQ bug # unless there is some delay here. if sys.platform == 'win32': time.sleep(0.2) @property def has_kernel(self): """Has a kernel been started that we are managing.""" return self.kernel is not None def _kill_kernel(self): """Kill the running kernel. This is a private method, callers should use shutdown_kernel(now=True). """ if self.has_kernel: # Signal the kernel to terminate (sends SIGKILL on Unix and calls # TerminateProcess() on Win32). try: self.kernel.kill() except OSError as e: # In Windows, we will get an Access Denied error if the process # has already terminated. Ignore it. if sys.platform == 'win32': if e.winerror != 5: raise # On Unix, we may get an ESRCH error if the process has already # terminated. Ignore it. else: from errno import ESRCH if e.errno != ESRCH: raise # Block until the kernel terminates. self.kernel.wait() self.kernel = None else: raise RuntimeError("Cannot kill kernel. No kernel is running!") def interrupt_kernel(self): """Interrupts the kernel by sending it a signal. Unlike ``signal_kernel``, this operation is well supported on all platforms. """ if self.has_kernel: if sys.platform == 'win32': from .zmq.parentpoller import ParentPollerWindows as Poller Poller.send_interrupt(self.kernel.win32_interrupt_event) else: self.kernel.send_signal(signal.SIGINT) else: raise RuntimeError("Cannot interrupt kernel. No kernel is running!") def signal_kernel(self, signum): """Sends a signal to the kernel. Note that since only SIGTERM is supported on Windows, this function is only useful on Unix systems. """ if self.has_kernel: self.kernel.send_signal(signum) else: raise RuntimeError("Cannot signal kernel. No kernel is running!") def is_alive(self): """Is the kernel process still running?""" if self.has_kernel: if self.kernel.poll() is None: return True else: return False else: # we don't have a kernel return False #----------------------------------------------------------------------------- # ABC Registration #----------------------------------------------------------------------------- KernelManagerABC.register(KernelManager)