Synnefo » snf-image-creator

# Copyright 2012 GRNET S.A. All rights reserved.

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#      copyright notice, this list of conditions and the following

#      disclaimer.

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#      copyright notice, this list of conditions and the following

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# THIS SOFTWARE IS PROVIDED BY GRNET S.A. ``AS IS'' AND ANY EXPRESS

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import sys

import pbs

import hashlib

class FatalError(Exception):

    pass

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)

class MD5:

    def __init__(self, output):

        self.out = output

    def compute(self, filename, size):

        MB = 2 ** 20

        BLOCKSIZE = 4 * MB  # 4MB

        prog_size = ((size + MB - 1) // MB)  # in MB

        progressbar = self.out.Progress(prog_size, "Calculating md5sum", 'mb')

        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) // MB)

        checksum = md5.hexdigest()

        progressbar.success(checksum)

        return checksum

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