def launch_kernel(cmd, stdin=None, stdout=None, stderr=None, env=None,
independent=False,
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).
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:
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
# and store it in an environment variable.
interrupt_event = ParentPollerWindows.create_interrupt_event()
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:
kwargs['creationflags'] = CREATE_NEW_PROCESS_GROUP
else:
pid = GetCurrentProcess()
handle = DuplicateHandle(pid, pid, pid, 0,
True, # Inheritable by new processes.
DUPLICATE_SAME_ACCESS)
env['JPY_PARENT_PID'] = str(int(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:
kwargs['preexec_fn'] = lambda: os.setsid()
else:
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()
return proc
def launch_kernel(cmd, stdin=None, stdout=None, stderr=None, env=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
env = env if (env is not None) else os.environ.copy()
encoding = getdefaultencoding(prefer_stream=False)
# 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')
from IPython.kernel.zmq.parentpoller import ParentPollerWindows
# Create a Win32 event for interrupting the kernel.
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.
if independent:
proc = Popen(cmd,
creationflags=512, # CREATE_NEW_PROCESS_GROUP
stdin=_stdin, stdout=_stdout, stderr=_stderr, env=env)
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)
# 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)
else:
if ipython_kernel:
cmd += ['--parent=1']
proc = Popen(cmd,
stdin=_stdin, stdout=_stdout, stderr=_stderr, cwd=cwd, env=env)
# 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
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
encoding = getdefaultencoding(prefer_stream=False)
# 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")
from IPython.kernel.zmq.parentpoller import ParentPollerWindows
# 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
stdin=_stdin,
stdout=_stdout,
stderr=_stderr,
env=os.environ,
)
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, DUPLICATE_SAME_ACCESS) # Inheritable by new processes.
cmd += ["--parent=%i" % handle]
proc = Popen(cmd, stdin=_stdin, stdout=_stdout, stderr=_stderr, cwd=cwd, env=os.environ)
# 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=os.environ,
)
else:
if ipython_kernel:
cmd += ["--parent=1"]
proc = Popen(cmd, stdin=_stdin, stdout=_stdout, stderr=_stderr, cwd=cwd, env=os.environ)
# 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
def launch_kernel(cmd, stdin=None, stdout=None, stderr=None, env=None,
independent=False,
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).
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:
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
# and store it in an environment variable.
interrupt_event = ParentPollerWindows.create_interrupt_event()
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:
kwargs['creationflags'] = CREATE_NEW_PROCESS_GROUP
else:
pid = GetCurrentProcess()
handle = DuplicateHandle(pid, pid, pid, 0,
True, # Inheritable by new processes.
DUPLICATE_SAME_ACCESS)
env['JPY_PARENT_PID'] = str(int(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:
kwargs['preexec_fn'] = lambda: os.setsid()
else:
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()
return proc