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launcher.py
258 lines | 9.5 KiB | text/x-python | PythonLexer
MinRK
test IPython.kernel
r9356 """Utilities for launching kernels
"""
Thomas Kluyver
Add mechanism to specify environment variables in kernel spec
r16349 # Copyright (c) IPython Development Team.
# Distributed under the terms of the Modified BSD License.
MinRK
test IPython.kernel
r9356
import os
import sys
from subprocess import Popen, PIPE
MinRK
Popen doesn't support unicode args on Windows Python 2
r14696 from IPython.utils.encoding import getdefaultencoding
MinRK
cast kernel cwd to bytes on Python 2 on Windows...
r9980 from IPython.utils.py3compat import cast_bytes_py2
MinRK
test IPython.kernel
r9356
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:
MinRK
check prefixes for swallowing kernel args...
r10426 if a == '--':
break
MinRK
test IPython.kernel
r9356 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('=')
MinRK
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r10426 name = split[0]
MinRK
add comment about argparse abbreviations
r10442 # 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.
MinRK
check prefixes for swallowing kernel args...
r10426 if any(alias.startswith(name) for alias in aliases):
MinRK
test IPython.kernel
r9356 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
MinRK
check prefixes for swallowing kernel args...
r10426 was_flag = name in flags
elif len(split) == 1 and any(flag.startswith(name) for flag in flags):
MinRK
test IPython.kernel
r9356 # strip flag, but don't swallow next, as flags don't take args
stripped.remove(a)
# return shortened list
return stripped
MinRK
use `python -m IPython.kernel` in IPython kernelspec...
r18434 def make_ipkernel_cmd(mod='IPython.kernel', executable=None, extra_arguments=[], **kw):
MinRK
test IPython.kernel
r9356 """Build Popen command list for launching an IPython kernel.
Parameters
----------
MinRK
use `python -m IPython.kernel` in IPython kernelspec...
r18434 mod : str, optional (default 'IPython.kernel')
A string of an IPython module whose __main__ starts an IPython kernel
MinRK
test IPython.kernel
r9356
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
MinRK
use `python -m IPython.kernel` in IPython kernelspec...
r18434 arguments = [ executable, '-m', mod, '-f', '{connection_file}' ]
MinRK
test IPython.kernel
r9356 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
Thomas Kluyver
Add mechanism to specify environment variables in kernel spec
r16349 def launch_kernel(cmd, stdin=None, stdout=None, stderr=None, env=None,
MinRK
test IPython.kernel
r9356 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
MinRK
Popen doesn't support unicode args on Windows Python 2
r14696
Thomas Kluyver
Pass Windows interrupt event to kernels as an environment variable...
r16717 env = env if (env is not None) else os.environ.copy()
MinRK
Popen doesn't support unicode args on Windows Python 2
r14696 encoding = getdefaultencoding(prefer_stream=False)
MinRK
test IPython.kernel
r9356 # Spawn a kernel.
if sys.platform == 'win32':
MinRK
Popen doesn't support unicode args on Windows Python 2
r14696 # Popen on Python 2 on Windows cannot handle unicode args or cwd
cmd = [ cast_bytes_py2(c, encoding) for c in cmd ]
MinRK
cast kernel cwd to bytes on Python 2 on Windows...
r9980 if cwd:
cwd = cast_bytes_py2(cwd, sys.getfilesystemencoding() or 'ascii')
MinRK
mv IPython.zmq to IPython.kernel.zmq
r9372 from IPython.kernel.zmq.parentpoller import ParentPollerWindows
MinRK
test IPython.kernel
r9356 # Create a Win32 event for interrupting the kernel.
interrupt_event = ParentPollerWindows.create_interrupt_event()
Thomas Kluyver
Pass Windows interrupt event to kernels as an environment variable...
r16717 # 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)
MinRK
test IPython.kernel
r9356 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
Thomas Kluyver
Add mechanism to specify environment variables in kernel spec
r16349 stdin=_stdin, stdout=_stdout, stderr=_stderr, env=env)
MinRK
test IPython.kernel
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,
Thomas Kluyver
Add mechanism to specify environment variables in kernel spec
r16349 stdin=_stdin, stdout=_stdout, stderr=_stderr, cwd=cwd, env=env)
MinRK
test IPython.kernel
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(),
Thomas Kluyver
Add mechanism to specify environment variables in kernel spec
r16349 stdin=_stdin, stdout=_stdout, stderr=_stderr, cwd=cwd, env=env)
MinRK
test IPython.kernel
r9356 else:
if ipython_kernel:
cmd += ['--parent=1']
proc = Popen(cmd,
Thomas Kluyver
Add mechanism to specify environment variables in kernel spec
r16349 stdin=_stdin, stdout=_stdout, stderr=_stderr, cwd=cwd, env=env)
MinRK
test IPython.kernel
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
MinRK
define and test IPython.kernel public API
r9376 __all__ = [
'swallow_argv',
'make_ipkernel_cmd',
'launch_kernel',
Rob Young
Pass host environment on to kernel...
r9433 ]