launcher.py
258 lines
| 9.2 KiB
| text/x-python
|
PythonLexer
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r9356 | """Utilities for launching kernels | ||
Authors: | ||||
* Min Ragan-Kelley | ||||
""" | ||||
#----------------------------------------------------------------------------- | ||||
# 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 | ||||
#----------------------------------------------------------------------------- | ||||
import os | ||||
import sys | ||||
from subprocess import Popen, PIPE | ||||
#----------------------------------------------------------------------------- | ||||
# Launching Kernels | ||||
#----------------------------------------------------------------------------- | ||||
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 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('=') | ||||
alias = split[0] | ||||
if 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 = alias in flags | ||||
elif alias in flags and len(split) == 1: | ||||
# 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(code, executable=None, extra_arguments=[], **kw): | ||||
"""Build Popen command list for launching an IPython kernel. | ||||
Parameters | ||||
---------- | ||||
code : str, | ||||
A string of Python code that imports and executes a kernel entry point. | ||||
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 | ||||
""" | ||||
# Build the kernel launch command. | ||||
if executable is None: | ||||
executable = sys.executable | ||||
arguments = [ executable, '-c', code, '-f', '{connection_file}' ] | ||||
arguments.extend(extra_arguments) | ||||
# Spawn a kernel. | ||||
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, | ||||
independent=False, | ||||
cwd=None, ipython_kernel=True, | ||||
**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 | ||||
else: | ||||
_stdout, _stderr = stdout, stderr | ||||
# Spawn a kernel. | ||||
if sys.platform == 'win32': | ||||
|
r9372 | from IPython.kernel.zmq.parentpoller import ParentPollerWindows | ||
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r9356 | # Create a Win32 event for interrupting the kernel. | ||
interrupt_event = ParentPollerWindows.create_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. | ||||
if independent: | ||||
proc = Popen(cmd, | ||||
creationflags=512, # CREATE_NEW_PROCESS_GROUP | ||||
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r9433 | stdin=_stdin, stdout=_stdout, stderr=_stderr, env=os.environ) | ||
|
r9356 | 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, | ||||
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r9433 | stdin=_stdin, stdout=_stdout, stderr=_stderr, cwd=cwd, env=os.environ) | ||
|
r9356 | |||
# 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(), | ||||
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r9433 | stdin=_stdin, stdout=_stdout, stderr=_stderr, cwd=cwd, env=os.environ) | ||
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r9356 | else: | ||
if ipython_kernel: | ||||
cmd += ['--parent=1'] | ||||
proc = Popen(cmd, | ||||
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r9433 | stdin=_stdin, stdout=_stdout, stderr=_stderr, cwd=cwd, env=os.environ) | ||
|
r9356 | |||
# 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 | ||||
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r9376 | __all__ = [ | ||
'swallow_argv', | ||||
'make_ipkernel_cmd', | ||||
'launch_kernel', | ||||
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r9433 | ] | ||