"""
exec_command
Implements exec_command function that is (almost) equivalent to
commands.getstatusoutput function but on NT, DOS systems the
returned status is actually correct (though, the returned status
values may be different by a factor). In addition, exec_command
takes keyword arguments for (re-)defining environment variables.
Provides functions:
exec_command --- execute command in a specified directory and
in the modified environment.
find_executable --- locate a command using info from environment
variable PATH. Equivalent to posix `which`
command.
Author: Pearu Peterson <pearu@cens.ioc.ee>
Created: 11 January 2003
Requires: Python 2.x
Successfully tested on:
======== ============ =================================================
os.name sys.platform comments
======== ============ =================================================
posix linux2 Debian (sid) Linux, Python 2.1.3+, 2.2.3+, 2.3.3
PyCrust 0.9.3, Idle 1.0.2
posix linux2 Red Hat 9 Linux, Python 2.1.3, 2.2.2, 2.3.2
posix sunos5 SunOS 5.9, Python 2.2, 2.3.2
posix darwin Darwin 7.2.0, Python 2.3
nt win32 Windows Me
Python 2.3(EE), Idle 1.0, PyCrust 0.7.2
Python 2.1.1 Idle 0.8
nt win32 Windows 98, Python 2.1.1. Idle 0.8
nt win32 Cygwin 98-4.10, Python 2.1.1(MSC) - echo tests
fail i.e. redefining environment variables may
not work. FIXED: don't use cygwin echo!
Comment: also `cmd /c echo` will not work
but redefining environment variables do work.
posix cygwin Cygwin 98-4.10, Python 2.3.3(cygming special)
nt win32 Windows XP, Python 2.3.3
======== ============ =================================================
Known bugs:
* Tests, that send messages to stderr, fail when executed from MSYS prompt
because the messages are lost at some point.
"""
from __future__ import division, absolute_import, print_function
__all__ = ['exec_command', 'find_executable']
import os
import sys
import subprocess
from numpy.distutils.misc_util import is_sequence, make_temp_file
from numpy.distutils import log
def temp_file_name():
fo, name = make_temp_file()
fo.close()
return name
def get_pythonexe():
pythonexe = sys.executable
if os.name in ['nt', 'dos']:
fdir, fn = os.path.split(pythonexe)
fn = fn.upper().replace('PYTHONW', 'PYTHON')
pythonexe = os.path.join(fdir, fn)
assert os.path.isfile(pythonexe), '%r is not a file' % (pythonexe,)
return pythonexe
def find_executable(exe, path=None, _cache={}):
"""Return full path of a executable or None.
Symbolic links are not followed.
"""
key = exe, path
try:
return _cache[key]
except KeyError:
pass
log.debug('find_executable(%r)' % exe)
orig_exe = exe
if path is None:
path = os.environ.get('PATH', os.defpath)
if os.name=='posix':
realpath = os.path.realpath
else:
realpath = lambda a:a
if exe.startswith('"'):
exe = exe[1:-1]
suffixes = ['']
if os.name in ['nt', 'dos', 'os2']:
fn, ext = os.path.splitext(exe)
extra_suffixes = ['.exe', '.com', '.bat']
if ext.lower() not in extra_suffixes:
suffixes = extra_suffixes
if os.path.isabs(exe):
paths = ['']
else:
paths = [ os.path.abspath(p) for p in path.split(os.pathsep) ]
for path in paths:
fn = os.path.join(path, exe)
for s in suffixes:
f_ext = fn+s
if not os.path.islink(f_ext):
f_ext = realpath(f_ext)
if os.path.isfile(f_ext) and os.access(f_ext, os.X_OK):
log.info('Found executable %s' % f_ext)
_cache[key] = f_ext
return f_ext
log.warn('Could not locate executable %s' % orig_exe)
return None
############################################################
def _preserve_environment( names ):
log.debug('_preserve_environment(%r)' % (names))
env = {}
for name in names:
env[name] = os.environ.get(name)
return env
def _update_environment( **env ):
log.debug('_update_environment(...)')
for name, value in env.items():
os.environ[name] = value or ''
def _supports_fileno(stream):
"""
Returns True if 'stream' supports the file descriptor and allows fileno().
"""
if hasattr(stream, 'fileno'):
try:
stream.fileno()
return True
except IOError:
return False
else:
return False
def exec_command(command, execute_in='', use_shell=None, use_tee=None,
_with_python = 1, **env ):
"""
Return (status,output) of executed command.
Parameters
----------
command : str
A concatenated string of executable and arguments.
execute_in : str
Before running command ``cd execute_in`` and after ``cd -``.
use_shell : {bool, None}, optional
If True, execute ``sh -c command``. Default None (True)
use_tee : {bool, None}, optional
If True use tee. Default None (True)
Returns
-------
res : str
Both stdout and stderr messages.
Notes
-----
On NT, DOS systems the returned status is correct for external commands.
Wild cards will not work for non-posix systems or when use_shell=0.
"""
log.debug('exec_command(%r,%s)' % (command,\
','.join(['%s=%r'%kv for kv in env.items()])))
if use_tee is None:
use_tee = os.name=='posix'
if use_shell is None:
use_shell = os.name=='posix'
execute_in = os.path.abspath(execute_in)
oldcwd = os.path.abspath(os.getcwd())
if __name__[-12:] == 'exec_command':
exec_dir = os.path.dirname(os.path.abspath(__file__))
elif os.path.isfile('exec_command.py'):
exec_dir = os.path.abspath('.')
else:
exec_dir = os.path.abspath(sys.argv[0])
if os.path.isfile(exec_dir):
exec_dir = os.path.dirname(exec_dir)
if oldcwd!=execute_in:
os.chdir(execute_in)
log.debug('New cwd: %s' % execute_in)
else:
log.debug('Retaining cwd: %s' % oldcwd)
oldenv = _preserve_environment( list(env.keys()) )
_update_environment( **env )
try:
st = _exec_command(command,
use_shell=use_shell,
use_tee=use_tee,
**env)
finally:
if oldcwd!=execute_in:
os.chdir(oldcwd)
log.debug('Restored cwd to %s' % oldcwd)
_update_environment(**oldenv)
return st
def _exec_command(command, use_shell=None, use_tee = None, **env):
"""
Internal workhorse for exec_command().
"""
if use_shell is None:
use_shell = os.name=='posix'
if use_tee is None:
use_tee = os.name=='posix'
if os.name == 'posix' and use_shell:
# On POSIX, subprocess always uses /bin/sh, override
sh = os.environ.get('SHELL', '/bin/sh')
if is_sequence(command):
command = [sh, '-c', ' '.join(command)]
else:
command = [sh, '-c', command]
use_shell = False
elif os.name == 'nt' and is_sequence(command):
# On Windows, join the string for CreateProcess() ourselves as
# subprocess does it a bit differently
command = ' '.join(_quote_arg(arg) for arg in command)
# Inherit environment by default
env = env or None
try:
proc = subprocess.Popen(command, shell=use_shell, env=env,
stdout=subprocess.PIPE,
stderr=subprocess.STDOUT,
universal_newlines=True)
except EnvironmentError:
# Return 127, as os.spawn*() and /bin/sh do
return 127, ''
text, err = proc.communicate()
# Another historical oddity
if text[-1:] == '\n':
text = text[:-1]
if use_tee and text:
print(text)
return proc.returncode, text
def _quote_arg(arg):
"""
Quote the argument for safe use in a shell command line.
"""
# If there is a quote in the string, assume relevants parts of the
# string are already quoted (e.g. '-I"C:\\Program Files\\..."')
if '"' not in arg and ' ' in arg:
return '"%s"' % arg
return arg
############################################################