exec-command.py

from memoize import memoize
import re
import shlex
import subprocess


def runcmd_get_exitcode(command, cwd=None):
    return runcmd(command, cwd=cwd)[0]

def runcmd_get_stdout(command, cwd=None):
    return runcmd(command, cwd=cwd)[1]


@memoize
def runcmd(command, cwd=None):
    """Advanced runcmd function with support for pipes and
    subcommands.
    E.g.:
    'ps aux | grep iTerm'
    'echo "foo" `ps aux | grep `echo iTerm` | cut -d \' \' -f 10` "bar"'
    """
    if isinstance(command, unicode):
        command = command.encode('utf-8')

    subcommand = re.match('^(.*?)\`(.*)\`(.*?)$', command,
                          re.MULTILINE)
    if subcommand:
        subresult = runcmd(subcommand.groups()[1])
        if subresult[0]:
            return subresult

        command = ''.join((
                subcommand.groups()[0],
                subresult[1],
                subcommand.groups()[2]))

    commands = command.split('|')
    prev_proc = None

    for cmd in commands:
        if prev_proc:
            input = prev_proc.stdout
        else:
            input = None

        prev_proc = subprocess.Popen(shlex.split(cmd),
                                     stderr=subprocess.PIPE,
                                     stdout=subprocess.PIPE,
                                     stdin=input,
                                     cwd=cwd)

    output, errors = prev_proc.communicate()
    return prev_proc.poll(), output, errors