Merge pull request #7099 from minrk/parent-env

remove special handling of ipython_kernel in launcher

IPython/kernel/launcher.py

@@ -1,258 +1,226 b''
 """Utilities for launching kernels
 """
 
 # Copyright (c) IPython Development Team.
 # Distributed under the terms of the Modified BSD License.
 
 import os
 import sys
 from subprocess import Popen, PIPE
 
 from IPython.utils.encoding import getdefaultencoding
 from IPython.utils.py3compat import cast_bytes_py2
 
 
 def swallow_argv(argv, aliases=None, flags=None):
     """strip frontend-specific aliases and flags from an argument list
     
     For use primarily in frontend apps that want to pass a subset of command-line
     arguments through to a subprocess, where frontend-specific flags and aliases
     should be removed from the list.
     
     Parameters
     ----------
     
     argv : list(str)
         The starting argv, to be filtered
     aliases : container of aliases (dict, list, set, etc.)
         The frontend-specific aliases to be removed
     flags : container of flags (dict, list, set, etc.)
         The frontend-specific flags to be removed
     
     Returns
     -------
     
     argv : list(str)
         The argv list, excluding flags and aliases that have been stripped
     """
     
     if aliases is None:
         aliases = set()
     if flags is None:
         flags = set()
     
     stripped = list(argv) # copy
     
     swallow_next = False
     was_flag = False
     for a in argv:
         if a == '--':
             break
         if swallow_next:
             swallow_next = False
             # last arg was an alias, remove the next one
             # *unless* the last alias has a no-arg flag version, in which
             # case, don't swallow the next arg if it's also a flag:
             if not (was_flag and a.startswith('-')):
                 stripped.remove(a)
                 continue
         if a.startswith('-'):
             split = a.lstrip('-').split('=')
             name = split[0]
             # we use startswith because argparse accepts any arg to be specified
             # by any leading section, as long as it is unique,
             # so `--no-br` means `--no-browser` in the notebook, etc.
             if any(alias.startswith(name) for alias in aliases):
                 stripped.remove(a)
                 if len(split) == 1:
                     # alias passed with arg via space
                     swallow_next = True
                     # could have been a flag that matches an alias, e.g. `existing`
                     # in which case, we might not swallow the next arg
                     was_flag = name in flags
             elif len(split) == 1 and any(flag.startswith(name) for flag in flags):
                 # strip flag, but don't swallow next, as flags don't take args
                 stripped.remove(a)
     
     # return shortened list
     return stripped
 
 
 def make_ipkernel_cmd(mod='IPython.kernel', executable=None, extra_arguments=[], **kw):
     """Build Popen command list for launching an IPython kernel.
 
     Parameters
     ----------
     mod : str, optional (default 'IPython.kernel')
         A string of an IPython module whose __main__ starts an IPython kernel
 
     executable : str, optional (default sys.executable)
         The Python executable to use for the kernel process.
 
     extra_arguments : list, optional
         A list of extra arguments to pass when executing the launch code.
     
     Returns
     -------
     
     A Popen command list
     """
     if executable is None:
         executable = sys.executable
     arguments = [ executable, '-m', mod, '-f', '{connection_file}' ]
     arguments.extend(extra_arguments)
-
-    if sys.platform == 'win32':
-
-        # If the kernel is running on pythonw and stdout/stderr are not been
-        # re-directed, it will crash when more than 4KB of data is written to
-        # stdout or stderr. This is a bug that has been with Python for a very
-        # long time; see http://bugs.python.org/issue706263.
-        # A cleaner solution to this problem would be to pass os.devnull to
-        # Popen directly. Unfortunately, that does not work.
-        if executable.endswith('pythonw.exe'):
-            arguments.append('--no-stdout')
-            arguments.append('--no-stderr')
-
+    
     return arguments
 
 
 def launch_kernel(cmd, stdin=None, stdout=None, stderr=None, env=None,
                         independent=False,
-                        cwd=None, ipython_kernel=True,
+                        cwd=None,
                         **kw
                         ):
     """ Launches a localhost kernel, binding to the specified ports.
 
     Parameters
     ----------
     cmd : Popen list,
         A string of Python code that imports and executes a kernel entry point.
 
     stdin, stdout, stderr : optional (default None)
         Standards streams, as defined in subprocess.Popen.
 
     independent : bool, optional (default False)
         If set, the kernel process is guaranteed to survive if this process
         dies. If not set, an effort is made to ensure that the kernel is killed
         when this process dies. Note that in this case it is still good practice
         to kill kernels manually before exiting.
 
     cwd : path, optional
         The working dir of the kernel process (default: cwd of this process).
 
-    ipython_kernel : bool, optional
-        Whether the kernel is an official IPython one,
-        and should get a bit of special treatment.
-
     Returns
     -------
     
     Popen instance for the kernel subprocess
     """
 
     # Popen will fail (sometimes with a deadlock) if stdin, stdout, and stderr
     # are invalid. Unfortunately, there is in general no way to detect whether
     # they are valid.  The following two blocks redirect them to (temporary)
     # pipes in certain important cases.
 
     # If this process has been backgrounded, our stdin is invalid. Since there
     # is no compelling reason for the kernel to inherit our stdin anyway, we'll
     # place this one safe and always redirect.
     redirect_in = True
     _stdin = PIPE if stdin is None else stdin
 
     # If this process in running on pythonw, we know that stdin, stdout, and
     # stderr are all invalid.
     redirect_out = sys.executable.endswith('pythonw.exe')
     if redirect_out:
-        _stdout = PIPE if stdout is None else stdout
-        _stderr = PIPE if stderr is None else stderr
+        blackhole = open(os.devnull, 'w')
+        _stdout = blackhole if stdout is None else stdout
+        _stderr = blackhole if stderr is None else stderr
     else:
         _stdout, _stderr = stdout, stderr
     
     env = env if (env is not None) else os.environ.copy()
 
     encoding = getdefaultencoding(prefer_stream=False)
+    kwargs = dict(
+        stdin=_stdin,
+        stdout=_stdout,
+        stderr=_stderr,
+        cwd=cwd,
+        env=env,
+    )
     
     # Spawn a kernel.
     if sys.platform == 'win32':
         # Popen on Python 2 on Windows cannot handle unicode args or cwd
         cmd = [ cast_bytes_py2(c, encoding) for c in cmd ]
         if cwd:
             cwd = cast_bytes_py2(cwd, sys.getfilesystemencoding() or 'ascii')
+            kwargs['cwd'] = cwd
         
         from IPython.kernel.zmq.parentpoller import ParentPollerWindows
-        # Create a Win32 event for interrupting the kernel.
+        # Create a Win32 event for interrupting the kernel
+        # and store it in an environment variable.
         interrupt_event = ParentPollerWindows.create_interrupt_event()
-        # Store this in an environment variable for third party kernels, but at
-        # present, our own kernel expects this as a command line argument.
-        env["IPY_INTERRUPT_EVENT"] = str(interrupt_event)
-        if ipython_kernel:
-            cmd += [ '--interrupt=%i' % interrupt_event ]
-
-            # If the kernel is running on pythonw and stdout/stderr are not been
-            # re-directed, it will crash when more than 4KB of data is written to
-            # stdout or stderr. This is a bug that has been with Python for a very
-            # long time; see http://bugs.python.org/issue706263.
-            # A cleaner solution to this problem would be to pass os.devnull to
-            # Popen directly. Unfortunately, that does not work.
-            if cmd[0].endswith('pythonw.exe'):
-                if stdout is None:
-                    cmd.append('--no-stdout')
-                if stderr is None:
-                    cmd.append('--no-stderr')
-
-        # Launch the kernel process.
+        env["JPY_INTERRUPT_EVENT"] = str(interrupt_event)
+        # deprecated old env name:
+        env["IPY_INTERRUPT_EVENT"] = env["JPY_INTERRUPT_EVENT"]
+
+        try:
+            from _winapi import DuplicateHandle, GetCurrentProcess, \
+                DUPLICATE_SAME_ACCESS, CREATE_NEW_PROCESS_GROUP
+        except:
+            from _subprocess import DuplicateHandle, GetCurrentProcess, \
+                DUPLICATE_SAME_ACCESS, CREATE_NEW_PROCESS_GROUP
+        # Launch the kernel process
         if independent:
-            proc = Popen(cmd,
-                         creationflags=512, # CREATE_NEW_PROCESS_GROUP
-                         stdin=_stdin, stdout=_stdout, stderr=_stderr, env=env)
+            kwargs['creationflags'] = CREATE_NEW_PROCESS_GROUP
         else:
-            if ipython_kernel:
-                try:
-                    from _winapi import DuplicateHandle, GetCurrentProcess, \
-                        DUPLICATE_SAME_ACCESS
-                except:
-                    from _subprocess import DuplicateHandle, GetCurrentProcess, \
-                        DUPLICATE_SAME_ACCESS
-                pid = GetCurrentProcess()
-                handle = DuplicateHandle(pid, pid, pid, 0,
-                                         True, # Inheritable by new processes.
-                                         DUPLICATE_SAME_ACCESS)
-                cmd +=[ '--parent=%i' % handle ]
-            
-            
-            proc = Popen(cmd,
-                         stdin=_stdin, stdout=_stdout, stderr=_stderr, cwd=cwd, env=env)
+            pid = GetCurrentProcess()
+            handle = DuplicateHandle(pid, pid, pid, 0,
+                                     True, # Inheritable by new processes.
+                                     DUPLICATE_SAME_ACCESS)
+            env['JPY_PARENT_PID'] = str(handle)
+        
+        proc = Popen(cmd, **kwargs)
 
         # Attach the interrupt event to the Popen objet so it can be used later.
         proc.win32_interrupt_event = interrupt_event
 
     else:
         if independent:
-            proc = Popen(cmd, preexec_fn=lambda: os.setsid(),
-                         stdin=_stdin, stdout=_stdout, stderr=_stderr, cwd=cwd, env=env)
+            kwargs['preexec_fn'] = lambda: os.setsid()
         else:
-            if ipython_kernel:
-                cmd += ['--parent=1']
-            proc = Popen(cmd,
-                         stdin=_stdin, stdout=_stdout, stderr=_stderr, cwd=cwd, env=env)
+            env['JPY_PARENT_PID'] = str(os.getpid())
+        
+        proc = Popen(cmd, **kwargs)
 
     # Clean up pipes created to work around Popen bug.
     if redirect_in:
         if stdin is None:
             proc.stdin.close()
-    if redirect_out:
-        if stdout is None:
-            proc.stdout.close()
-        if stderr is None:
-            proc.stderr.close()
 
     return proc
 
 __all__ = [
     'swallow_argv',
     'make_ipkernel_cmd',
     'launch_kernel',
 ]

IPython/kernel/manager.py

@@ -1,452 +1,451 b''
 """Base class to manage a running kernel"""
 
 # Copyright (c) IPython Development Team.
 # Distributed under the terms of the Modified BSD License.
 
 from __future__ import absolute_import
 
 from contextlib import contextmanager
 import os
 import re
 import signal
 import sys
 import time
 import warnings
 try:
     from queue import Empty  # Py 3
 except ImportError:
     from Queue import Empty  # Py 2
 
 import zmq
 
 from IPython.utils.importstring import import_item
 from IPython.utils.localinterfaces import is_local_ip, local_ips
 from IPython.utils.path import get_ipython_dir
 from IPython.utils.traitlets import (
     Any, Instance, Unicode, List, Bool, Type, DottedObjectName
 )
 from IPython.kernel import (
     launch_kernel,
     kernelspec,
 )
 from .connect import ConnectionFileMixin
 from .zmq.session import Session
 from .managerabc import (
     KernelManagerABC
 )
 
 
 class KernelManager(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 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_spec_manager = Instance(kernelspec.KernelSpecManager)
     
     def _kernel_spec_manager_default(self):
         return kernelspec.KernelSpecManager(ipython_dir=self.ipython_dir)
     
     kernel_name = Unicode(kernelspec.NATIVE_KERNEL_NAME)
     
     kernel_spec = Instance(kernelspec.KernelSpec)
     
     def _kernel_spec_default(self):
         return self.kernel_spec_manager.get_kernel_spec(self.kernel_name)
     
     def _kernel_name_changed(self, name, old, new):
         if new == 'python':
             self.kernel_name = kernelspec.NATIVE_KERNEL_NAME
             # This triggered another run of this function, so we can exit now
             return
         self.kernel_spec = self.kernel_spec_manager.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)
     
     ipython_dir = Unicode()
     def _ipython_dir_default(self):
         return get_ipython_dir()
 
     # 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, extra_arguments=None):
         """replace templated args (e.g. {connection_file})"""
         extra_arguments = extra_arguments or []
         if self.kernel_cmd:
             cmd = self.kernel_cmd + extra_arguments
         else:
             cmd = self.kernel_spec.argv + extra_arguments
 
         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
         extra_arguments = kw.pop('extra_arguments', [])
         kernel_cmd = self.format_kernel_cmd(extra_arguments=extra_arguments)
         if self.kernel_cmd:
             # If kernel_cmd has been set manually, don't refer to a kernel spec
             env = os.environ
         else:
             # Environment variables from kernel spec are added to os.environ
             env = os.environ.copy()
             env.update(self.kernel_spec.env or {})
         # launch the kernel subprocess
         self.kernel = self._launch_kernel(kernel_cmd, env=env,
-                                    ipython_kernel=self.ipython_kernel,
                                     **kw)
         self.start_restarter()
         self._connect_control_socket()
 
     def request_shutdown(self, restart=False):
         """Send a shutdown request via control channel
         
         On Windows, this just kills kernels instead, because the shutdown
         messages don't work.
         """
         content = dict(restart=restart)
         msg = self.session.msg("shutdown_request", content=content)
         self.session.send(self._control_socket, msg)
 
     def finish_shutdown(self, waittime=1, pollinterval=0.1):
         """Wait for kernel shutdown, then kill process if it doesn't shutdown.
         
         This does not send shutdown requests - use :meth:`request_shutdown`
         first.
         """
         for i in range(int(waittime/pollinterval)):
             if self.is_alive():
                 time.sleep(pollinterval)
             else:
                 break
         else:
             # OK, we've waited long enough.
             if self.has_kernel:
                 self._kill_kernel()
 
     def cleanup(self, connection_file=True):
         """Clean up resources when the kernel is shut down"""
         if connection_file:
             self.cleanup_connection_file()
 
         self.cleanup_ipc_files()
         self._close_control_socket()
 
     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()
 
         if now:
             self._kill_kernel()
         else:
             self.request_shutdown(restart=restart)
             # 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.finish_shutdown()
 
         self.cleanup(connection_file=not restart)
 
     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)
 
     @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
 
 
 KernelManagerABC.register(KernelManager)
 
 
 def start_new_kernel(startup_timeout=60, kernel_name='python', **kwargs):
     """Start a new kernel, and return its Manager and Client"""
     km = KernelManager(kernel_name=kernel_name)
     km.start_kernel(**kwargs)
     kc = km.client()
     kc.start_channels()
 
     kc.kernel_info()
     kc.get_shell_msg(block=True, timeout=startup_timeout)
 
     # Flush channels
     for channel in (kc.shell_channel, kc.iopub_channel):
         while True:
             try:
                 channel.get_msg(block=True, timeout=0.1)
             except Empty:
                 break
     return km, kc
 
 @contextmanager
 def run_kernel(**kwargs):
     """Context manager to create a kernel in a subprocess.
     
     The kernel is shut down when the context exits.
     
     Returns
     -------
     kernel_client: connected KernelClient instance
     """
     km, kc = start_new_kernel(**kwargs)
     try:
         yield kc
     finally:
         kc.stop_channels()
         km.shutdown_kernel(now=True)

IPython/kernel/zmq/kernelapp.py

@@ -1,391 +1,388 b''
 """An Application for launching a kernel"""
 
 # Copyright (c) IPython Development Team.
 # Distributed under the terms of the Modified BSD License.
 
 from __future__ import print_function
 
 import atexit
 import os
 import sys
 import signal
 
 import zmq
 from zmq.eventloop import ioloop
 from zmq.eventloop.zmqstream import ZMQStream
 
 from IPython.core.ultratb import FormattedTB
 from IPython.core.application import (
     BaseIPythonApplication, base_flags, base_aliases, catch_config_error
 )
 from IPython.core.profiledir import ProfileDir
 from IPython.core.shellapp import (
     InteractiveShellApp, shell_flags, shell_aliases
 )
 from IPython.utils import io
 from IPython.utils.path import filefind
 from IPython.utils.traitlets import (
     Any, Instance, Dict, Unicode, Integer, Bool, DottedObjectName, Type,
 )
 from IPython.utils.importstring import import_item
 from IPython.kernel import write_connection_file
 from IPython.kernel.connect import ConnectionFileMixin
 
 # local imports
 from .heartbeat import Heartbeat
 from .ipkernel import IPythonKernel
 from .parentpoller import ParentPollerUnix, ParentPollerWindows
 from .session import (
     Session, session_flags, session_aliases, default_secure,
 )
 from .zmqshell import ZMQInteractiveShell
 
 #-----------------------------------------------------------------------------
 # Flags and Aliases
 #-----------------------------------------------------------------------------
 
 kernel_aliases = dict(base_aliases)
 kernel_aliases.update({
     'ip' : 'IPKernelApp.ip',
     'hb' : 'IPKernelApp.hb_port',
     'shell' : 'IPKernelApp.shell_port',
     'iopub' : 'IPKernelApp.iopub_port',
     'stdin' : 'IPKernelApp.stdin_port',
     'control' : 'IPKernelApp.control_port',
     'f' : 'IPKernelApp.connection_file',
-    'parent': 'IPKernelApp.parent_handle',
     'transport': 'IPKernelApp.transport',
 })
-if sys.platform.startswith('win'):
-    kernel_aliases['interrupt'] = 'IPKernelApp.interrupt'
 
 kernel_flags = dict(base_flags)
 kernel_flags.update({
     'no-stdout' : (
             {'IPKernelApp' : {'no_stdout' : True}},
             "redirect stdout to the null device"),
     'no-stderr' : (
             {'IPKernelApp' : {'no_stderr' : True}},
             "redirect stderr to the null device"),
     'pylab' : (
         {'IPKernelApp' : {'pylab' : 'auto'}},
         """Pre-load matplotlib and numpy for interactive use with
         the default matplotlib backend."""),
 })
 
 # inherit flags&aliases for any IPython shell apps
 kernel_aliases.update(shell_aliases)
 kernel_flags.update(shell_flags)
 
 # inherit flags&aliases for Sessions
 kernel_aliases.update(session_aliases)
 kernel_flags.update(session_flags)
 
 _ctrl_c_message = """\
 NOTE: When using the `ipython kernel` entry point, Ctrl-C will not work.
 
 To exit, you will have to explicitly quit this process, by either sending
 "quit" from a client, or using Ctrl-\\ in UNIX-like environments.
 
 To read more about this, see https://github.com/ipython/ipython/issues/2049
 
 """
 
 #-----------------------------------------------------------------------------
 # Application class for starting an IPython Kernel
 #-----------------------------------------------------------------------------
 
 class IPKernelApp(BaseIPythonApplication, InteractiveShellApp,
         ConnectionFileMixin):
     name='ipython-kernel'
     aliases = Dict(kernel_aliases)
     flags = Dict(kernel_flags)
     classes = [IPythonKernel, ZMQInteractiveShell, ProfileDir, Session]
     # the kernel class, as an importstring
     kernel_class = Type('IPython.kernel.zmq.ipkernel.IPythonKernel', config=True,
                         klass='IPython.kernel.zmq.kernelbase.Kernel',
     help="""The Kernel subclass to be used.
     
     This should allow easy re-use of the IPKernelApp entry point
     to configure and launch kernels other than IPython's own.
     """)
     kernel = Any()
     poller = Any() # don't restrict this even though current pollers are all Threads
     heartbeat = Instance(Heartbeat)
     ports = Dict()
     
     # connection info:
     
     @property
     def abs_connection_file(self):
         if os.path.basename(self.connection_file) == self.connection_file:
             return os.path.join(self.profile_dir.security_dir, self.connection_file)
         else:
             return self.connection_file
         
 
     # streams, etc.
     no_stdout = Bool(False, config=True, help="redirect stdout to the null device")
     no_stderr = Bool(False, config=True, help="redirect stderr to the null device")
     outstream_class = DottedObjectName('IPython.kernel.zmq.iostream.OutStream',
         config=True, help="The importstring for the OutStream factory")
     displayhook_class = DottedObjectName('IPython.kernel.zmq.displayhook.ZMQDisplayHook',
         config=True, help="The importstring for the DisplayHook factory")
 
     # polling
-    parent_handle = Integer(0, config=True,
+    parent_handle = Integer(int(os.environ.get('JPY_PARENT_PID') or 0), config=True,
         help="""kill this process if its parent dies.  On Windows, the argument
         specifies the HANDLE of the parent process, otherwise it is simply boolean.
         """)
-    interrupt = Integer(0, config=True,
+    interrupt = Integer(int(os.environ.get('JPY_INTERRUPT_EVENT') or 0), config=True,
         help="""ONLY USED ON WINDOWS
         Interrupt this process when the parent is signaled.
         """)
 
     def init_crash_handler(self):
         # Install minimal exception handling
         sys.excepthook = FormattedTB(mode='Verbose', color_scheme='NoColor',
                                      ostream=sys.__stdout__)
 
     def init_poller(self):
         if sys.platform == 'win32':
             if self.interrupt or self.parent_handle:
                 self.poller = ParentPollerWindows(self.interrupt, self.parent_handle)
         elif self.parent_handle:
             self.poller = ParentPollerUnix()
 
     def _bind_socket(self, s, port):
         iface = '%s://%s' % (self.transport, self.ip)
         if self.transport == 'tcp':
             if port <= 0:
                 port = s.bind_to_random_port(iface)
             else:
                 s.bind("tcp://%s:%i" % (self.ip, port))
         elif self.transport == 'ipc':
             if port <= 0:
                 port = 1
                 path = "%s-%i" % (self.ip, port)
                 while os.path.exists(path):
                     port = port + 1
                     path = "%s-%i" % (self.ip, port)
             else:
                 path = "%s-%i" % (self.ip, port)
             s.bind("ipc://%s" % path)
         return port
 
     def write_connection_file(self):
         """write connection info to JSON file"""
         cf = self.abs_connection_file
         self.log.debug("Writing connection file: %s", cf)
         write_connection_file(cf, ip=self.ip, key=self.session.key, transport=self.transport,
         shell_port=self.shell_port, stdin_port=self.stdin_port, hb_port=self.hb_port,
         iopub_port=self.iopub_port, control_port=self.control_port)
     
     def cleanup_connection_file(self):
         cf = self.abs_connection_file
         self.log.debug("Cleaning up connection file: %s", cf)
         try:
             os.remove(cf)
         except (IOError, OSError):
             pass
         
         self.cleanup_ipc_files()
     
     def init_connection_file(self):
         if not self.connection_file:
             self.connection_file = "kernel-%s.json"%os.getpid()
         try:
             self.connection_file = filefind(self.connection_file, ['.', self.profile_dir.security_dir])
         except IOError:
             self.log.debug("Connection file not found: %s", self.connection_file)
             # This means I own it, so I will clean it up:
             atexit.register(self.cleanup_connection_file)
             return
         try:
             self.load_connection_file()
         except Exception:
             self.log.error("Failed to load connection file: %r", self.connection_file, exc_info=True)
             self.exit(1)
     
     def init_sockets(self):
         # Create a context, a session, and the kernel sockets.
         self.log.info("Starting the kernel at pid: %i", os.getpid())
         context = zmq.Context.instance()
         # Uncomment this to try closing the context.
         # atexit.register(context.term)
 
         self.shell_socket = context.socket(zmq.ROUTER)
         self.shell_socket.linger = 1000
         self.shell_port = self._bind_socket(self.shell_socket, self.shell_port)
         self.log.debug("shell ROUTER Channel on port: %i" % self.shell_port)
 
         self.iopub_socket = context.socket(zmq.PUB)
         self.iopub_socket.linger = 1000
         self.iopub_port = self._bind_socket(self.iopub_socket, self.iopub_port)
         self.log.debug("iopub PUB Channel on port: %i" % self.iopub_port)
 
         self.stdin_socket = context.socket(zmq.ROUTER)
         self.stdin_socket.linger = 1000
         self.stdin_port = self._bind_socket(self.stdin_socket, self.stdin_port)
         self.log.debug("stdin ROUTER Channel on port: %i" % self.stdin_port)
 
         self.control_socket = context.socket(zmq.ROUTER)
         self.control_socket.linger = 1000
         self.control_port = self._bind_socket(self.control_socket, self.control_port)
         self.log.debug("control ROUTER Channel on port: %i" % self.control_port)
     
     def init_heartbeat(self):
         """start the heart beating"""
         # heartbeat doesn't share context, because it mustn't be blocked
         # by the GIL, which is accessed by libzmq when freeing zero-copy messages
         hb_ctx = zmq.Context()
         self.heartbeat = Heartbeat(hb_ctx, (self.transport, self.ip, self.hb_port))
         self.hb_port = self.heartbeat.port
         self.log.debug("Heartbeat REP Channel on port: %i" % self.hb_port)
         self.heartbeat.start()
     
     def log_connection_info(self):
         """display connection info, and store ports"""
         basename = os.path.basename(self.connection_file)
         if basename == self.connection_file or \
             os.path.dirname(self.connection_file) == self.profile_dir.security_dir:
             # use shortname
             tail = basename
             if self.profile != 'default':
                 tail += " --profile %s" % self.profile
         else:
             tail = self.connection_file
         lines = [
             "To connect another client to this kernel, use:",
             "    --existing %s" % tail,
         ]
         # log connection info
         # info-level, so often not shown.
         # frontends should use the %connect_info magic
         # to see the connection info
         for line in lines:
             self.log.info(line)
         # also raw print to the terminal if no parent_handle (`ipython kernel`)
         if not self.parent_handle:
             io.rprint(_ctrl_c_message)
             for line in lines:
                 io.rprint(line)
 
         self.ports = dict(shell=self.shell_port, iopub=self.iopub_port,
                                 stdin=self.stdin_port, hb=self.hb_port,
                                 control=self.control_port)
 
     def init_blackhole(self):
         """redirects stdout/stderr to devnull if necessary"""
         if self.no_stdout or self.no_stderr:
             blackhole = open(os.devnull, 'w')
             if self.no_stdout:
                 sys.stdout = sys.__stdout__ = blackhole
             if self.no_stderr:
                 sys.stderr = sys.__stderr__ = blackhole
     
     def init_io(self):
         """Redirect input streams and set a display hook."""
         if self.outstream_class:
             outstream_factory = import_item(str(self.outstream_class))
             sys.stdout = outstream_factory(self.session, self.iopub_socket, u'stdout')
             sys.stderr = outstream_factory(self.session, self.iopub_socket, u'stderr')
         if self.displayhook_class:
             displayhook_factory = import_item(str(self.displayhook_class))
             sys.displayhook = displayhook_factory(self.session, self.iopub_socket)
 
     def init_signal(self):
         signal.signal(signal.SIGINT, signal.SIG_IGN)
 
     def init_kernel(self):
         """Create the Kernel object itself"""
         shell_stream = ZMQStream(self.shell_socket)
         control_stream = ZMQStream(self.control_socket)
         
         kernel_factory = self.kernel_class.instance
 
         kernel = kernel_factory(parent=self, session=self.session,
                                 shell_streams=[shell_stream, control_stream],
                                 iopub_socket=self.iopub_socket,
                                 stdin_socket=self.stdin_socket,
                                 log=self.log,
                                 profile_dir=self.profile_dir,
                                 user_ns=self.user_ns,
         )
         kernel.record_ports(self.ports)
         self.kernel = kernel
 
     def init_gui_pylab(self):
         """Enable GUI event loop integration, taking pylab into account."""
 
         # Provide a wrapper for :meth:`InteractiveShellApp.init_gui_pylab`
         # to ensure that any exception is printed straight to stderr.
         # Normally _showtraceback associates the reply with an execution,
         # which means frontends will never draw it, as this exception
         # is not associated with any execute request.
 
         shell = self.shell
         _showtraceback = shell._showtraceback
         try:
             # replace error-sending traceback with stderr
             def print_tb(etype, evalue, stb):
                 print ("GUI event loop or pylab initialization failed",
                        file=io.stderr)
                 print (shell.InteractiveTB.stb2text(stb), file=io.stderr)
             shell._showtraceback = print_tb
             InteractiveShellApp.init_gui_pylab(self)
         finally:
             shell._showtraceback = _showtraceback
 
     def init_shell(self):
         self.shell = getattr(self.kernel, 'shell', None)
         if self.shell:
             self.shell.configurables.append(self)
 
     @catch_config_error
     def initialize(self, argv=None):
         super(IPKernelApp, self).initialize(argv)
         default_secure(self.config)
         self.init_blackhole()
         self.init_connection_file()
         self.init_poller()
         self.init_sockets()
         self.init_heartbeat()
         # writing/displaying connection info must be *after* init_sockets/heartbeat
         self.log_connection_info()
         self.write_connection_file()
         self.init_io()
         self.init_signal()
         self.init_kernel()
         # shell init steps
         self.init_path()
         self.init_shell()
         if self.shell:
             self.init_gui_pylab()
             self.init_extensions()
             self.init_code()
         # flush stdout/stderr, so that anything written to these streams during
         # initialization do not get associated with the first execution request
         sys.stdout.flush()
         sys.stderr.flush()
 
     def start(self):
         if self.poller is not None:
             self.poller.start()
         self.kernel.start()
         try:
             ioloop.IOLoop.instance().start()
         except KeyboardInterrupt:
             pass
 
 launch_new_instance = IPKernelApp.launch_instance
 
 def main():
     """Run an IPKernel as an application"""
     app = IPKernelApp.instance()
     app.initialize()
     app.start()
 
 
 if __name__ == '__main__':
     main()