utils.py

#
# Copyright (c) 2010-2013 Liraz Siri <liraz@turnkeylinux.org>
#
# This file is part of TKLBAM (TurnKey GNU/Linux BAckup and Migration).
#
# TKLBAM is open source software; you can redistribute it and/or
# modify it under the terms of the GNU General Public License as
# published by the Free Software Foundation; either version 3 of
# the License, or (at your option) any later version.
#
import os
from os.path import *

import executil
import shutil
import stat
import datetime

from StringIO import StringIO

def remove_any(path):
    """Remove a path whether it is a file or a directory.
       Return: True if removed, False if nothing to remove"""

    if not lexists(path):
        return False

    if not islink(path) and isdir(path):
        shutil.rmtree(path)
    else:
        os.remove(path)

    return True

class AttrDict(dict):
    def __getattr__(self, name):
        if name in self:
            return self[name]
        raise AttributeError("no such attribute '%s'" % name)

    def __setattr__(self, name, val):
        self[name] = val

def is_writeable(fpath):
    try:
        file(fpath, "w+")
        return True
    except IOError:
        return False

# workaround for shutil.move across-filesystem bugs
def move(src, dst):
    st = os.lstat(src)

    is_symlink = stat.S_ISLNK(st.st_mode)

    if os.path.isdir(dst):
        dst = os.path.join(dst, os.path.basename(os.path.abspath(src)))

    if is_symlink:
        linkto = os.readlink(src)
        os.symlink(linkto, dst)
        os.unlink(src)
    else:
        shutil.move(src, dst)
        os.lchown(dst, st.st_uid, st.st_gid)

def apply_overlay(src, dst, olist_path):
    orig_cwd = os.getcwd()
    os.chdir(src)
    executil.getoutput("tar --create --files-from=%s | tar --extract --directory %s" %
                       (olist_path, executil.mkarg(dst)))

    os.chdir(orig_cwd)

def fmt_title(title, c='='):
    return title + "\n" + c * len(title) + "\n"

def fmt_timestamp():

    fh = StringIO()

    s = "### %s ###" % datetime.datetime.now().ctime()
    print >> fh, "#" * len(s)
    print >> fh, s
    print >> fh, "#" * len(s)

    return fh.getvalue()

def path_global_or_local(path_global, path_local):
    """Return global path if writeable, otherwise return local path"""
    if os.access(os.path.dirname(path_global), os.W_OK):
        return path_global

    return path_local

def iamroot():
    return os.getuid() == 0