try:
from datetime import datetime
except ImportError:
datetime = None
import logging
import re
from subprocess import PIPE, Popen
from pickle import dumps

log = logging.getLogger(__name__)
PUBLIC_DIR_RE = re.compile(r'.*?/usr/lib/python(\d(?:.\d+)?)/(site|dist)-packages')


class memoize:
def __init__(self, func):
self.func = func
self.cache = {}

def __call__(self, *args, **kwargs):
key = dumps((args, kwargs))
if key not in self.cache:
self.cache[key] = self.func(*args, **kwargs)
return self.cache[key]


def execute(command, cwd=None, env=None, log_output=None):
"""Execute external shell commad.

:param cdw: currennt working directory
:param env: environment
:param log_output:
* opened log file or path to this file, or
* None if output should be included in the returned dict, or
* False if output should be redirectored to stdout/stderr
"""
args = {'shell': True, 'cwd': cwd, 'env': env}
close = False
if log_output is False:
pass
elif log_output is None:
args.update(stdout=PIPE, stderr=PIPE)
elif log_output:
if isinstance(log_output, str):
close = True
log_output = open(log_output, 'a')
if datetime:
log_output.write('\n# command executed on {}'.format(datetime.now().isoformat()))
log_output.write('\n$ {}\n'.format(command))
log_output.flush()
args.update(stdout=log_output, stderr=log_output)

log.debug('invoking: %s', command)
with Popen(command, **args) as process:
stdout, stderr = process.communicate()
close and log_output.close()
return dict(returncode=process.returncode,
stdout=stdout and str(stdout, 'utf-8'),
stderr=stderr and str(stderr, 'utf-8'))