shellutils.py

#
# Licensed to the Apache Software Foundation (ASF) under one or more
# contributor license agreements.  See the NOTICE file distributed with
# this work for additional information regarding copyright ownership.
# The ASF licenses this file to You under the Apache License, Version 2.0
# (the "License"); you may not use this file except in compliance with
# the License.  You may obtain a copy of the License at
#
#    http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
#

from __future__ import print_function
import os
import shutil
import subprocess
import sys


if sys.version_info >= (2, 7):
    subprocess_check_output = subprocess.check_output
    subprocess_check_call = subprocess.check_call
else:
    # SPARK-8763
    # backported from subprocess module in Python 2.7
    def subprocess_check_output(*popenargs, **kwargs):
        if 'stdout' in kwargs:
            raise ValueError('stdout argument not allowed, it will be overridden.')
        process = subprocess.Popen(stdout=subprocess.PIPE, *popenargs, **kwargs)
        output, unused_err = process.communicate()
        retcode = process.poll()
        if retcode:
            cmd = kwargs.get("args")
            if cmd is None:
                cmd = popenargs[0]
            raise subprocess.CalledProcessError(retcode, cmd, output=output)
        return output

    # backported from subprocess module in Python 2.7
    def subprocess_check_call(*popenargs, **kwargs):
        retcode = call(*popenargs, **kwargs)
        if retcode:
            cmd = kwargs.get("args")
            if cmd is None:
                cmd = popenargs[0]
            raise CalledProcessError(retcode, cmd)
        return 0


def exit_from_command_with_retcode(cmd, retcode):
    print("[error] running", ' '.join(cmd), "; received return code", retcode)
    sys.exit(int(os.environ.get("CURRENT_BLOCK", 255)))


def rm_r(path):
    """
    Given an arbitrary path, properly remove it with the correct Python construct if it exists.
    From: http://stackoverflow.com/a/9559881
    """

    if os.path.isdir(path):
        shutil.rmtree(path)
    elif os.path.exists(path):
        os.remove(path)


def run_cmd(cmd, return_output=False):
    """
    Given a command as a list of arguments will attempt to execute the command
    and, on failure, print an error message and exit.
    """

    if not isinstance(cmd, list):
        cmd = cmd.split()
    try:
        if return_output:
            return subprocess_check_output(cmd)
        else:
            return subprocess_check_call(cmd)
    except subprocess.CalledProcessError as e:
        exit_from_command_with_retcode(e.cmd, e.returncode)


def is_exe(path):
    """
    Check if a given path is an executable file.
    From: http://stackoverflow.com/a/377028
    """

    return os.path.isfile(path) and os.access(path, os.X_OK)


def which(program):
    """
    Find and return the given program by its absolute path or 'None' if the program cannot be found.
    From: http://stackoverflow.com/a/377028
    """

    fpath = os.path.split(program)[0]

    if fpath:
        if is_exe(program):
            return program
    else:
        for path in os.environ.get("PATH").split(os.pathsep):
            path = path.strip('"')
            exe_file = os.path.join(path, program)
            if is_exe(exe_file):
                return exe_file
    return None