Synnefo » snf-ganeti » ganeti-local

#

#

# Copyright (C) 2013 Google Inc.

#

# 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.

"""File storage functions.

"""

from ganeti import errors

from ganeti import utils

DF_M_UNIT = 'M'

DF_MIN_NUM_COLS = 4

DF_NUM_LINES = 2

def _ParseDfResult(dfresult):

  """Parses the output of the call of the 'df' tool.

     @type dfresult: string

     @param dfresult: output of the 'df' call

     @return: tuple (size, free) of the total and free disk space in MebiBytes

  """

  df_lines = dfresult.splitlines()

  if len(df_lines) != DF_NUM_LINES:

    raise errors.CommandError("'df' output has wrong number of lines: %s" %

                              len(df_lines))

  df_values = df_lines[1].strip().split()

  if len(df_values) < DF_MIN_NUM_COLS:

    raise errors.CommandError("'df' output does not have enough columns: %s" %

                              len(df_values))

  size_str = df_values[1]

  if size_str[-1] != DF_M_UNIT:

    raise errors.CommandError("'df': 'size' not given in Mebibytes.")

  free_str = df_values[3]

  if free_str[-1] != DF_M_UNIT:

    raise errors.CommandError("'df': 'free' not given in Mebibytes.")

  size = int(size_str[:-1])

  free = int(free_str[:-1])

  return (size, free)

def GetSpaceInfo(path, _parsefn=_ParseDfResult):

  """Retrieves the free and total space of the device where the file is

     located.

     @type path: string

     @param path: Path of the file whose embracing device's capacity is

       reported.

     @type _parsefn: function

     @param _parsefn: Function that parses the output of the 'df' command;

       given as parameter to make this code more testable.

     @return: a dictionary containing 'vg_size' and 'vg_free'

  """

  cmd = ['df', '-BM', path]

  result = utils.RunCmd(cmd)

  if result.failed:

    raise errors.CommandError("Failed to run 'df' command: %s - %s" %

                              (result.fail_reason, result.output))

  (size, free) = _parsefn(result.stdout)

  return {"vg_size": size, "vg_free": free}