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Backport PR #9976: Let IPython.lib.guisupport detect terminal-integrated event loops...
Backport PR #9976: Let IPython.lib.guisupport detect terminal-integrated event loops Closes gh-9974 This is a bit more invasive than most backported changes, but it fixes a regression in IPython 5. My thinking: - The `guisupport` APIs that worked before should continue working until/unless we deprecate them. - There should be a common way to check if an event loop is already running in both the terminal and an IPython kernel. - It should be possible to check for any event loop, not just Qt and Wx (which `guisupport` has checks for). My plan is to make a public attribute `shell.active_eventloop`, which is either None or a string naming the event loop which IPython will run when waiting for input. E.g. `qt` or `gtk3`. (Todo: should we also expose the event loop object in cases where there is one? Not sure if anything useful can be done with it). This PR adds that attribute for terminal IPython; if we agree on it I'll make a separate PR for ipykernel. The functions in guisupport then become a convenient shortcut for checking this, and we can decide whether to deprecate them in favour or something more uniform, or add similar convenience functions for other common event loops. Signed-off-by: Thomas Kluyver <thomas@kluyver.me.uk>

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script.py
272 lines | 8.4 KiB | text/x-python | PythonLexer
"""Magic functions for running cells in various scripts."""
from __future__ import print_function
# Copyright (c) IPython Development Team.
# Distributed under the terms of the Modified BSD License.
import errno
import os
import sys
import signal
import time
from subprocess import Popen, PIPE
import atexit
from IPython.core import magic_arguments
from IPython.core.magic import (
Magics, magics_class, line_magic, cell_magic
)
from IPython.lib.backgroundjobs import BackgroundJobManager
from IPython.utils import py3compat
from IPython.utils.process import arg_split
from traitlets import List, Dict, default
#-----------------------------------------------------------------------------
# Magic implementation classes
#-----------------------------------------------------------------------------
def script_args(f):
"""single decorator for adding script args"""
args = [
magic_arguments.argument(
'--out', type=str,
help="""The variable in which to store stdout from the script.
If the script is backgrounded, this will be the stdout *pipe*,
instead of the stderr text itself.
"""
),
magic_arguments.argument(
'--err', type=str,
help="""The variable in which to store stderr from the script.
If the script is backgrounded, this will be the stderr *pipe*,
instead of the stderr text itself.
"""
),
magic_arguments.argument(
'--bg', action="store_true",
help="""Whether to run the script in the background.
If given, the only way to see the output of the command is
with --out/err.
"""
),
magic_arguments.argument(
'--proc', type=str,
help="""The variable in which to store Popen instance.
This is used only when --bg option is given.
"""
),
]
for arg in args:
f = arg(f)
return f
@magics_class
class ScriptMagics(Magics):
"""Magics for talking to scripts
This defines a base `%%script` cell magic for running a cell
with a program in a subprocess, and registers a few top-level
magics that call %%script with common interpreters.
"""
script_magics = List(
help="""Extra script cell magics to define
This generates simple wrappers of `%%script foo` as `%%foo`.
If you want to add script magics that aren't on your path,
specify them in script_paths
""",
).tag(config=True)
@default('script_magics')
def _script_magics_default(self):
"""default to a common list of programs"""
defaults = [
'sh',
'bash',
'perl',
'ruby',
'python',
'python2',
'python3',
'pypy',
]
if os.name == 'nt':
defaults.extend([
'cmd',
])
return defaults
script_paths = Dict(
help="""Dict mapping short 'ruby' names to full paths, such as '/opt/secret/bin/ruby'
Only necessary for items in script_magics where the default path will not
find the right interpreter.
"""
).tag(config=True)
def __init__(self, shell=None):
super(ScriptMagics, self).__init__(shell=shell)
self._generate_script_magics()
self.job_manager = BackgroundJobManager()
self.bg_processes = []
atexit.register(self.kill_bg_processes)
def __del__(self):
self.kill_bg_processes()
def _generate_script_magics(self):
cell_magics = self.magics['cell']
for name in self.script_magics:
cell_magics[name] = self._make_script_magic(name)
def _make_script_magic(self, name):
"""make a named magic, that calls %%script with a particular program"""
# expand to explicit path if necessary:
script = self.script_paths.get(name, name)
@magic_arguments.magic_arguments()
@script_args
def named_script_magic(line, cell):
# if line, add it as cl-flags
if line:
line = "%s %s" % (script, line)
else:
line = script
return self.shebang(line, cell)
# write a basic docstring:
named_script_magic.__doc__ = \
"""%%{name} script magic
Run cells with {script} in a subprocess.
This is a shortcut for `%%script {script}`
""".format(**locals())
return named_script_magic
@magic_arguments.magic_arguments()
@script_args
@cell_magic("script")
def shebang(self, line, cell):
"""Run a cell via a shell command
The `%%script` line is like the #! line of script,
specifying a program (bash, perl, ruby, etc.) with which to run.
The rest of the cell is run by that program.
Examples
--------
::
In [1]: %%script bash
...: for i in 1 2 3; do
...: echo $i
...: done
1
2
3
"""
argv = arg_split(line, posix = not sys.platform.startswith('win'))
args, cmd = self.shebang.parser.parse_known_args(argv)
try:
p = Popen(cmd, stdout=PIPE, stderr=PIPE, stdin=PIPE)
except OSError as e:
if e.errno == errno.ENOENT:
print("Couldn't find program: %r" % cmd[0])
return
else:
raise
if not cell.endswith('\n'):
cell += '\n'
cell = cell.encode('utf8', 'replace')
if args.bg:
self.bg_processes.append(p)
self._gc_bg_processes()
if args.out:
self.shell.user_ns[args.out] = p.stdout
if args.err:
self.shell.user_ns[args.err] = p.stderr
self.job_manager.new(self._run_script, p, cell, daemon=True)
if args.proc:
self.shell.user_ns[args.proc] = p
return
try:
out, err = p.communicate(cell)
except KeyboardInterrupt:
try:
p.send_signal(signal.SIGINT)
time.sleep(0.1)
if p.poll() is not None:
print("Process is interrupted.")
return
p.terminate()
time.sleep(0.1)
if p.poll() is not None:
print("Process is terminated.")
return
p.kill()
print("Process is killed.")
except OSError:
pass
except Exception as e:
print("Error while terminating subprocess (pid=%i): %s" \
% (p.pid, e))
return
out = py3compat.bytes_to_str(out)
err = py3compat.bytes_to_str(err)
if args.out:
self.shell.user_ns[args.out] = out
else:
sys.stdout.write(out)
sys.stdout.flush()
if args.err:
self.shell.user_ns[args.err] = err
else:
sys.stderr.write(err)
sys.stderr.flush()
def _run_script(self, p, cell):
"""callback for running the script in the background"""
p.stdin.write(cell)
p.stdin.close()
p.wait()
@line_magic("killbgscripts")
def killbgscripts(self, _nouse_=''):
"""Kill all BG processes started by %%script and its family."""
self.kill_bg_processes()
print("All background processes were killed.")
def kill_bg_processes(self):
"""Kill all BG processes which are still running."""
for p in self.bg_processes:
if p.poll() is None:
try:
p.send_signal(signal.SIGINT)
except:
pass
time.sleep(0.1)
for p in self.bg_processes:
if p.poll() is None:
try:
p.terminate()
except:
pass
time.sleep(0.1)
for p in self.bg_processes:
if p.poll() is None:
try:
p.kill()
except:
pass
self._gc_bg_processes()
def _gc_bg_processes(self):
self.bg_processes = [p for p in self.bg_processes if p.poll() is None]