+# -*- coding: utf-8 -*-
+#
# Copyright 2012 GRNET S.A. All rights reserved.
#
# Redistribution and use in source and binary forms, with or
# interpreted as representing official policies, either expressed
# or implied, of GRNET S.A.
-import pbs
+"""This module provides various helper functions to be used by other parts of
+the package.
+"""
+
+import sh
+import hashlib
+import time
+import os
+import re
+
+
+class FatalError(Exception):
+ """Fatal Error exception of snf-image-creator"""
+ pass
def get_command(command):
+ """Return a file system binary 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)
+ return sh.Command(fullpath)
raise exception
try:
- return pbs.__getattr__(command)
- except pbs.CommadNotFount as e:
+ return sh.__getattr__(command)
+ except sh.CommandNotFound as e:
return find_sbin_command(command, e)
+
+
+def get_kvm_binary():
+ """Returns the path to the kvm binary and some extra arguments if needed"""
+
+ uname = get_command('uname')
+ which = get_command('which')
+
+ machine = str(uname('-m')).strip()
+ if re.match('i[3-6]86', machine):
+ machine = 'i386'
+
+ binary = which('qemu-system-%s' % machine)
+
+ needed_args = "--enable-kvm",
+
+ if binary is None:
+ return which('kvm'), tuple()
+
+ return binary, needed_args
+
+
+def try_fail_repeat(command, *args):
+ """Execute a command multiple times until it succeeds"""
+ times = (0.1, 0.5, 1, 2)
+ i = iter(times)
+ while True:
+ try:
+ command(*args)
+ return
+ except sh.ErrorReturnCode:
+ try:
+ wait = i.next()
+ except StopIteration:
+ break
+ time.sleep(wait)
+
+ raise FatalError("Command: `%s %s' failed" % (command, " ".join(args)))
+
+
+def free_space(dirname):
+ """Compute the free space in a directory"""
+ stat = os.statvfs(dirname)
+ return stat.f_bavail * stat.f_frsize
+
+
+class MD5:
+ """Represents MD5 computations"""
+ def __init__(self, output):
+ """Create an MD5 instance"""
+ self.out = output
+
+ def compute(self, filename, size):
+ """Compute the MD5 checksum of a file"""
+ 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
+
+# vim: set sta sts=4 shiftwidth=4 sw=4 et ai :