1 # -*- coding: utf-8 -*-
3 # Copyright 2012 GRNET S.A. All rights reserved.
5 # Redistribution and use in source and binary forms, with or
6 # without modification, are permitted provided that the following
9 # 1. Redistributions of source code must retain the above
10 # copyright notice, this list of conditions and the following
13 # 2. Redistributions in binary form must reproduce the above
14 # copyright notice, this list of conditions and the following
15 # disclaimer in the documentation and/or other materials
16 # provided with the distribution.
18 # THIS SOFTWARE IS PROVIDED BY GRNET S.A. ``AS IS'' AND ANY EXPRESS
19 # OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
20 # WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
21 # PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL GRNET S.A OR
22 # CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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24 # LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
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34 # or implied, of GRNET S.A.
36 """This module provides various helper functions to be used by other parts of
46 class FatalError(Exception):
47 """Fatal Error exception of snf-image-creator"""
51 def get_command(command):
52 """Return a file system binary command"""
53 def find_sbin_command(command, exception):
54 search_paths = ['/usr/local/sbin', '/usr/sbin', '/sbin']
55 for fullpath in map(lambda x: "%s/%s" % (x, command), search_paths):
56 if os.path.exists(fullpath) and os.access(fullpath, os.X_OK):
57 return sh.Command(fullpath)
61 return sh.__getattr__(command)
62 except sh.CommandNotFound as e:
63 return find_sbin_command(command, e)
66 def try_fail_repeat(command, *args):
67 """Execute a command multiple times until it succeeds"""
68 times = (0.1, 0.5, 1, 2)
74 except sh.ErrorReturnCode:
81 raise FatalError("Command: `%s %s' failed" % (command, " ".join(args)))
84 def free_space(dirname):
85 """Compute the free space in a directory"""
86 stat = os.statvfs(dirname)
87 return stat.f_bavail * stat.f_frsize
91 """Represents MD5 computations"""
92 def __init__(self, output):
93 """Create an MD5 instance"""
96 def compute(self, filename, size):
97 """Compute the MD5 checksum of a file"""
99 BLOCKSIZE = 4 * MB # 4MB
101 prog_size = ((size + MB - 1) // MB) # in MB
102 progressbar = self.out.Progress(prog_size, "Calculating md5sum", 'mb')
104 with open(filename, "r") as src:
107 length = min(left, BLOCKSIZE)
108 data = src.read(length)
111 progressbar.goto((size - left) // MB)
113 checksum = md5.hexdigest()
114 progressbar.success(checksum)
118 # vim: set sta sts=4 shiftwidth=4 sw=4 et ai :