#!/usr/bin/env python
# Contributed by Robert Gogolok <gogo@cs.uni-sb.de>

# TODO:
# - export plugins
# - document usage

'''This tool exports the bcfg2 configuration for the specified client to an output directory.

First the specified output directory is created.

Then for every <Path> entry of the specified host
the appropriate directory under the output directory is created.
The metadata information get stored in an index file in the output directory. 

The format of the index file is:
user,group,permission,/path/to/file
'''
__revision__ = '$Revision: 221 $'

import logging, lxml.etree, Bcfg2.Logging, Bcfg2.Server.Core
import Bcfg2.Server.Plugins.Metadata, Bcfg2.Server.Plugin
import sys,os,time,errno
from optparse import OptionParser

DEFAULT_BCFG2_CONFIGFILE = "/etc/bcfg2.conf"
DEFAULT_FAM_STEPS = 20
DEFAULT_INDEX_FILE = "index.txt"
TOOLNAME = "bcfg2-export-config"

def buildConfiguration(core, client):
  '''Build client configuration.'''
  return core.BuildConfiguration(client)

def write_entry(indexfile, user, group, permission, path):
  '''Write an entry to the file listing Path entries in outputdir.'''
  f = open(outputdir + '/%s' % indexfile, 'a')
  f.write("%s,%s,%s,%s\n" % (user, group, permission, path))
  f.close()
  logger.info("Wrote entry." )

class PathNotBuild(Exception):
  def __init__(self, value):
    self.value = value
  def __str__(self):
    return repr(self.value)


def handlePathEntry(indexfile, cfg):
  '''Store file content of an <Path name='/path/to/file' ...>...</Path> entry
  in the appropriate directory under the output directory.'''
  name       = cfg.get('name')
  permission = cfg.get('perms').rjust(4,'0')
  user       = cfg.get('owner')
  group      = cfg.get('group')

  logger.info("\nHandling Path entry %s >>>" % name)

  # directory creation
  logger.info("Creating directory %s" % ( os.path.dirname(outputdir + name)) )
  try:
    os.makedirs(os.path.dirname(outputdir + name))
  except OSError,err:
    if err.errno != errno.EEXIST:
      raise
  except:
    logger.error("Fatal error during directory creation!")
    raise

  # write config file
  f = open(outputdir + name, "w" )
  try:
    f.write(cfg.text)
  except: # plugin throw an exception and therefore there is no content => None
    raise PathNotBuild(name)
  f.close()

  # write entry
  try:
    write_entry(indexfile, user, group, permission, name)
  except:
    logger.error("Writing entry to configfiles failed!")
    raise

  logger.info("<<<")

if __name__ == '__main__':
  Bcfg2.Logging.setup_logging('%s' % TOOLNAME, to_syslog=False)
  logger = logging.getLogger('%s' % TOOLNAME)

  # parse command line options, arguments
  parser = OptionParser(usage = "%prog [options] client outputdir", version = __revision__)
  parser.add_option("-C", "--config-file", action="store", dest="configfile", 
      help="Use given bcfg2.conf file, by default %s" % DEFAULT_BCFG2_CONFIGFILE)

  parser.add_option("-f", "--fam-steps", action="store", dest="famsteps",
      type = "int", help="How many times to handle fam/gamin events, by default %s" % DEFAULT_FAM_STEPS)

  parser.add_option("-i", "--index-filename", action="store", dest="indexfile",
      help="Filename for index of exported Path entries, by default %s" % DEFAULT_INDEX_FILE)

  parser.set_defaults(configfile=DEFAULT_BCFG2_CONFIGFILE, famsteps = DEFAULT_FAM_STEPS, indexfile = DEFAULT_INDEX_FILE)

  (options, args) = parser.parse_args()

  # ensure client hostname and outputdir is given
  if len(args) != 2:
    parser.error("incorrect number of arguments.")

  client = args[0]
  outputdir = args[1]

  # stop if output directory exists
  if os.path.exists(outputdir):
    logger.error("Output directory already exists, won't override!")
    raise SystemExit, 1

  logger.info("Generating configuration for %s" % client)

  # load Bcfg2 Core
  try:
    logger.debug("Trying to load core...")
    bcore = Bcfg2.Server.Core.Core({}, options.configfile)
  except Bcfg2.Server.Core.CoreInitError, msg:
    logger.error("Core load failed because %s" % msg)
    raise SystemExit, 1
  else:
    logger.debug("Core loaded.")

  # FAM service handling
  for i in range(options.famsteps):
    logger.info("FAM service handling: %s to go..." % str(options.famsteps - i) )
    bcore.fam.Service()
    time.sleep(0.5)

  # get configuration for client
  try:
    client_config = buildConfiguration( bcore, client)
  except:
    logger.error("Building client configuration failed. Exiting...")
    raise SystemExit, 1

  # client could be without a group, not listed in client.xml ...
  if client_config.tag == 'error':
    logger.error("Building client configuration failed. Exiting...")
    raise SystemExit, 1

  # handle <Path> entries
  for configfile in client_config.findall(".//ConfigFile") + client_config.findall(".//Path"):
    try:
      handlePathEntry(options.indexfile, configfile)
    except PathNotBuild, e:
      logger.error("Error: Plugin failed to generate file content for Path %s !" % e)
      raise SystemExit, 1
    except:
      logger.error("unknown error, I give up")
      raise SystemExit, 1