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Merge pull request #1921 from bfroehle/_1890_magic_arguments_docstring...
Merge pull request #1921 from bfroehle/_1890_magic_arguments_docstring magic_arguments: dedent but otherwise preserve indentation. Previously magic_arguments stripped all whitespace at the beginning of each line, interfering with formatting syntax which relies on indentation to give context (e.g., code blocks). Now the docstring text is passed through dedent to strip the global indentation before being handed off to `RawDescriptionHelpFormatter` which preserves any remaining indentation. Thanks to @rkern for suggesting the solution approach. Closes gh-1890.

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script.py
216 lines | 7.0 KiB | text/x-python | PythonLexer
"""Magic functions for running cells in various scripts."""
#-----------------------------------------------------------------------------
# Copyright (c) 2012 The IPython Development Team.
#
# Distributed under the terms of the Modified BSD License.
#
# The full license is in the file COPYING.txt, distributed with this software.
#-----------------------------------------------------------------------------
#-----------------------------------------------------------------------------
# Imports
#-----------------------------------------------------------------------------
# Stdlib
import os
import re
import sys
from subprocess import Popen, PIPE
# Our own packages
from IPython.config.configurable import Configurable
from IPython.core import magic_arguments
from IPython.core.error import UsageError
from IPython.core.magic import (
Magics, magics_class, line_magic, cell_magic
)
from IPython.lib.backgroundjobs import BackgroundJobManager
from IPython.testing.skipdoctest import skip_doctest
from IPython.utils import py3compat
from IPython.utils.process import find_cmd, FindCmdError, arg_split
from IPython.utils.traitlets import List, Dict
#-----------------------------------------------------------------------------
# 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.
"""
),
]
for arg in args:
f = arg(f)
return f
@magics_class
class ScriptMagics(Magics, Configurable):
"""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(config=True,
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
""",
)
def _script_magics_default(self):
"""default to a common list of programs if we find them"""
defaults = []
to_try = []
if os.name == 'nt':
defaults.append('cmd')
to_try.append('powershell')
to_try.extend([
'sh',
'bash',
'perl',
'ruby',
'python3',
'pypy',
])
for cmd in to_try:
if cmd in self.script_paths:
defaults.append(cmd)
else:
try:
find_cmd(cmd)
except FindCmdError:
# command not found, ignore it
pass
except ImportError:
# Windows without pywin32, find_cmd doesn't work
pass
else:
defaults.append(cmd)
return defaults
script_paths = Dict(config=True,
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.
"""
)
def __init__(self, shell=None):
Configurable.__init__(self, config=shell.config)
self._generate_script_magics()
Magics.__init__(self, shell=shell)
self.job_manager = BackgroundJobManager()
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)
p = Popen(cmd, stdout=PIPE, stderr=PIPE, stdin=PIPE)
cell = cell.encode('utf8', 'replace')
if args.bg:
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)
return
out, err = p.communicate(cell)
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()