util.py

# Copyright 2012 GRNET S.A. All rights reserved.
#
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# without modification, are permitted provided that the following
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#      disclaimer.
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#   2. Redistributions in binary form must reproduce the above
#      copyright notice, this list of conditions and the following
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# CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
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import sys
import pbs
import hashlib
from colors import red, green, yellow
from progress.bar import Bar


class FatalError(Exception):
    pass


silent = False


def get_command(command):
    def find_sbin_command(command, exception):
        search_paths = ['/usr/local/sbin', '/usr/sbin', '/sbin']
        for fullpath in map(lambda x: "%s/%s" % (x, command), search_paths):
            if os.path.exists(fullpath) and os.access(fullpath, os.X_OK):
                return pbs.Command(fullpath)
        raise exception

    try:
        return pbs.__getattr__(command)
    except pbs.CommadNotFount as e:
        return find_sbin_command(command, e)


def error(msg, new_line=True):
    nl = "\n" if new_line else ''
    sys.stderr.write(red('Error: %s' % msg) + nl)


def warn(msg, new_line=True):
    if not silent:
        nl = "\n" if new_line else ''
        sys.stderr.write(yellow("Warning: %s" % msg) + nl)


def success(msg, new_line=True):
    if not silent:
        nl = "\n" if new_line else ''
        sys.stdout.write(green(msg) + nl)
        if not nl:
            sys.stdout.flush()


def output(msg="", new_line=True):
    if not silent:
        nl = "\n" if new_line else ''
        sys.stdout.write(msg + nl)
        if not nl:
            sys.stdout.flush()


def progress(message='', bar_type="default"):

    MESSAGE_LENGTH = 30

    suffix = {
        'default': '%(index)d/%(max)d',
        'percent': '%(percent)d%%',
        'b': '%(index)d/%(max)d B',
        'kb': '%(index)d/%(max)d KB',
        'mb': '%(index)d/%(max)d MB'
    }

    bar = Bar()
    bar.message = message.ljust(MESSAGE_LENGTH)
    bar.fill = '#'
    bar.suffix = suffix[bar_type]
    bar.bar_prefix = ' ['
    bar.bar_suffix = '] '

    return bar


def md5(filename, size):

    BLOCKSIZE = 2 ** 22  # 4MB

    progressbar = progress("Calculating md5sum:", 'mb')
    progressbar.max = ((size + 2 ** 20 - 1) // (2 ** 20))
    md5 = hashlib.md5()
    with open(filename, "r") as src:
        left = size
        while left > 0:
            length = min(left, BLOCKSIZE)
            data = src.read(length)
            md5.update(data)
            left -= length
            progressbar.goto((size - left) // (2 ** 20))

    checksum = md5.hexdigest()
    output("\rCalculating md5sum...\033[K", False)
    success(checksum)

    return checksum

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