Source Code for Module ganeti.utils.nodesetup

  1  # 
  2  # 
  3   
  4  # Copyright (C) 2006, 2007, 2010, 2011 Google Inc. 
  5  # 
  6  # This program is free software; you can redistribute it and/or modify 
  7  # it under the terms of the GNU General Public License as published by 
  8  # the Free Software Foundation; either version 2 of the License, or 
  9  # (at your option) any later version. 
 10  # 
 11  # This program is distributed in the hope that it will be useful, but 
 12  # WITHOUT ANY WARRANTY; without even the implied warranty of 
 13  # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU 
 14  # General Public License for more details. 
 15  # 
 16  # You should have received a copy of the GNU General Public License 
 17  # along with this program; if not, write to the Free Software 
 18  # Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 
 19  # 02110-1301, USA. 
 20   
 21  """Utility functions for manipulating /etc/hosts. 
 22   
 23  """ 
 24   
 25  from cStringIO import StringIO 
 26   
 27  from ganeti import constants 
 28   
 29  from ganeti.utils import algo 
 30  from ganeti.utils import io 
 31   
 32   
 33 -def SetEtcHostsEntry(file_name, ip, hostname, aliases): 
 34    """Sets the name of an IP address and hostname in /etc/hosts. 
 35   
 36    @type file_name: str 
 37    @param file_name: path to the file to modify (usually C{/etc/hosts}) 
 38    @type ip: str 
 39    @param ip: the IP address 
 40    @type hostname: str 
 41    @param hostname: the hostname to be added 
 42    @type aliases: list 
 43    @param aliases: the list of aliases to add for the hostname 
 44   
 45    """ 
 46    # Ensure aliases are unique 
 47    names = algo.UniqueSequence([hostname] + aliases) 
 48   
 49    out = StringIO() 
 50   
 51    def _write_entry(written): 
 52      if not written: 
 53        out.write("%s\t%s\n" % (ip, " ".join(names))) 
 54      return True 
 55   
 56    written = False 
 57    for line in io.ReadFile(file_name).splitlines(True): 
 58      fields = line.split() 
 59      if fields and not fields[0].startswith("#") and ip == fields[0]: 
 60        written = _write_entry(written) 
 61      else: 
 62        out.write(line) 
 63    _write_entry(written) 
 64   
 65    io.WriteFile(file_name, data=out.getvalue(), mode=0644) 
 66   
 67   
 68 -def AddHostToEtcHosts(hostname, ip): 
 69    """Wrapper around SetEtcHostsEntry. 
 70   
 71    @type hostname: str 
 72    @param hostname: a hostname that will be resolved and added to 
 73        L{constants.ETC_HOSTS} 
 74    @type ip: str 
 75    @param ip: The ip address of the host 
 76   
 77    """ 
 78    SetEtcHostsEntry(constants.ETC_HOSTS, ip, hostname, [hostname.split(".")[0]]) 
 79   
 80   
 81 -def RemoveEtcHostsEntry(file_name, hostname): 
 82    """Removes a hostname from /etc/hosts. 
 83   
 84    IP addresses without names are removed from the file. 
 85   
 86    @type file_name: str 
 87    @param file_name: path to the file to modify (usually C{/etc/hosts}) 
 88    @type hostname: str 
 89    @param hostname: the hostname to be removed 
 90   
 91    """ 
 92    out = StringIO() 
 93   
 94    for line in io.ReadFile(file_name).splitlines(True): 
 95      fields = line.split() 
 96      if len(fields) > 1 and not fields[0].startswith("#"): 
 97        names = fields[1:] 
 98        if hostname in names: 
 99          while hostname in names: 
100            names.remove(hostname) 
101          if names: 
102            out.write("%s %s\n" % (fields[0], " ".join(names))) 
103          continue 
104   
105      out.write(line) 
106   
107    io.WriteFile(file_name, data=out.getvalue(), mode=0644) 
108   
109   
110 -def RemoveHostFromEtcHosts(hostname): 
111    """Wrapper around RemoveEtcHostsEntry. 
112   
113    @type hostname: str 
114    @param hostname: hostname that will be resolved and its 
115        full and shot name will be removed from 
116        L{constants.ETC_HOSTS} 
117   
118    """ 
119    RemoveEtcHostsEntry(constants.ETC_HOSTS, hostname) 
120    RemoveEtcHostsEntry(constants.ETC_HOSTS, hostname.split(".")[0]) 
121