Synnefo » snf-ganeti

# Copyright (C) 2007 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.

"""QA configuration.

"""

import yaml

import qa_error

cfg = None

options = None

def Load(path):

  """Loads the passed configuration file.

  """

  global cfg

  f = open(path, 'r')

  try:

    cfg = yaml.load(f.read())

  finally:

    f.close()

  Validate()

def Validate():

  if len(cfg['nodes']) < 1:

    raise qa_error.Error("Need at least one node")

  if len(cfg['instances']) < 1:

    raise qa_error.Error("Need at least one instance")

def get(name, default=None):

  return cfg.get(name, default)

def TestEnabled(test):

  """Returns True if the given test is enabled."""

  return cfg.get('tests', {}).get(test, False)

def GetMasterNode():

  return cfg['nodes'][0]

def AcquireInstance():

  """Returns an instance which isn't in use.

  """

  # Filter out unwanted instances

  tmp_flt = lambda inst: not inst.get('_used', False)

  instances = filter(tmp_flt, cfg['instances'])

  del tmp_flt

  if len(instances) == 0:

    raise qa_error.OutOfInstancesError("No instances left")

  inst = instances[0]

  inst['_used'] = True

  return inst

def ReleaseInstance(inst):

  inst['_used'] = False

def AcquireNode(exclude=None):

  """Returns the least used node.

  """

  master = GetMasterNode()

  # Filter out unwanted nodes

  # TODO: Maybe combine filters

  if exclude is None:

    nodes = cfg['nodes'][:]

  else:

    nodes = filter(lambda node: node != exclude, cfg['nodes'])

  tmp_flt = lambda node: node.get('_added', False) or node == master

  nodes = filter(tmp_flt, nodes)

  del tmp_flt

  if len(nodes) == 0:

    raise qa_error.OutOfNodesError("No nodes left")

  # Get node with least number of uses

  def compare(a, b):

    result = cmp(a.get('_count', 0), b.get('_count', 0))

    if result == 0:

      result = cmp(a['primary'], b['primary'])

    return result

  nodes.sort(cmp=compare)

  node = nodes[0]

  node['_count'] = node.get('_count', 0) + 1

  return node

def ReleaseNode(node):

  node['_count'] = node.get('_count', 0) - 1