Synnefo » snf-ganeti » Ganeti ExtStorage providers

#!/usr/bin/env python

#

# Copyright (C) 2012 Greek Research and Technology Network

#

# This program is free 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 2 of the License, or

# (at your option) any later version.

#

# This program is distributed in the hope that it will be useful, but

# WITHOUT ANY WARRANTY; without even the implied warranty of

# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

# General Public License for more details.

#

# You should have received a copy of the GNU General Public License

# along with this program; if not, write to the Free Software

# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA

# 02110-1301, USA.

"""Create a new file under a shared directory

This program creates a new file inside a shared directory. It will be

used to host a disk Image. It takes it's input from environment variables.

Specifically the following variables should be present:

 - VOL_NAME: The name of the new Image file

 - VOL_SIZE: The size of the new Image (in mebibytes)

Returns O after successfull creation, 1 on failure

"""

import os

import sys

import errno

sys.path.append("/usr/share/ganeti")

from ganeti import utils

# Default shared directory

SHARED_DIR = "/srv/ganeti/shared-file-storage"

def ReadEnv():

  """Read the mandatory enviromental variables

  """

  name = os.getenv("VOL_NAME")

  if name is None:

    sys.stderr.write('The environment variable VOL_NAME is missing.\n')

    return None

  size = os.getenv("VOL_SIZE")

  if size is None:

    sys.stderr.write('The environment variable VOL_SIZE is missing.\n')

    return None

  shared_dir_param = os.getenv("EXTP_SHARED_DIR")

  if shared_dir_param is not None:

    sys.stderr.write('Found shared dir param, value: %s\n' % shared_dir_param)

  return (name, size, shared_dir_param)

def main():

  sys.stderr.write('Creation started: reading environment...\n')

  # Read environment

  env = ReadEnv()

  if env is None:

    sys.stderr.write('Wrong environment. Aborting\n')

    return 1

  file_name, size, shared_dir_param = env

  if shared_dir_param is None:

    shared_dir_param = SHARED_DIR

  file_path = utils.PathJoin(shared_dir_param, file_name)

  sys.stderr.write('Read environment successfully: file name: %s, '

                   'size: %sMB\n' % (file_path, size))

  # Check if directory exists

  if not os.path.isdir(shared_dir_param):

    sys.stderr.write('%s is not a valid directory. Aborting' % shared_dir_param)

    return 1

  # Create file

  try:

    fd = os.open(file_path, os.O_RDWR | os.O_CREAT | os.O_EXCL)

    f = os.fdopen(fd, "w")

    f.truncate(int(size) * 1024 * 1024)

    f.close()

  except EnvironmentError, err:

    if err.errno == errno.EEXIST:

      sys.stderr.write('File already existing: %s\n' % file_path)

      return 1

    sys.stderr.write('Error in file creation: %\n' % str(err))

    return 1

  sys.stderr.write('Image file created successfully\n')

  return 0

if __name__ == "__main__":

    sys.exit(main())