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  import os 
 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    aliases = algo.UniqueSequence([hostname] + aliases)[1:] 
 48   
 49    def _WriteEtcHosts(fd): 
 50      # Duplicating file descriptor because os.fdopen's result will automatically 
 51      # close the descriptor, but we would still like to have its functionality. 
 52      out = os.fdopen(os.dup(fd), "w") 
 53      try: 
 54        for line in io.ReadFile(file_name).splitlines(True): 
 55          fields = line.split() 
 56          if fields and not fields[0].startswith("#") and ip == fields[0]: 
 57            continue 
 58          out.write(line) 
 59   
 60        out.write("%s\t%s" % (ip, hostname)) 
 61        if aliases: 
 62          out.write(" %s" % " ".join(aliases)) 
 63        out.write("\n") 
 64        out.flush() 
 65      finally: 
 66        out.close() 
 67   
 68    io.WriteFile(file_name, fn=_WriteEtcHosts, mode=0644) 
 69   
 70   
 71 -def AddHostToEtcHosts(hostname, ip): 
 72    """Wrapper around SetEtcHostsEntry. 
 73   
 74    @type hostname: str 
 75    @param hostname: a hostname that will be resolved and added to 
 76        L{constants.ETC_HOSTS} 
 77    @type ip: str 
 78    @param ip: The ip address of the host 
 79   
 80    """ 
 81    SetEtcHostsEntry(constants.ETC_HOSTS, ip, hostname, [hostname.split(".")[0]]) 
 82   
 83   
 84 -def RemoveEtcHostsEntry(file_name, hostname): 
 85    """Removes a hostname from /etc/hosts. 
 86   
 87    IP addresses without names are removed from the file. 
 88   
 89    @type file_name: str 
 90    @param file_name: path to the file to modify (usually C{/etc/hosts}) 
 91    @type hostname: str 
 92    @param hostname: the hostname to be removed 
 93   
 94    """ 
 95    def _WriteEtcHosts(fd): 
 96      # Duplicating file descriptor because os.fdopen's result will automatically 
 97      # close the descriptor, but we would still like to have its functionality. 
 98      out = os.fdopen(os.dup(fd), "w") 
 99      try: 
100        for line in io.ReadFile(file_name).splitlines(True): 
101          fields = line.split() 
102          if len(fields) > 1 and not fields[0].startswith("#"): 
103            names = fields[1:] 
104            if hostname in names: 
105              while hostname in names: 
106                names.remove(hostname) 
107              if names: 
108                out.write("%s %s\n" % (fields[0], " ".join(names))) 
109              continue 
110   
111          out.write(line) 
112   
113        out.flush() 
114      finally: 
115        out.close() 
116   
117    io.WriteFile(file_name, fn=_WriteEtcHosts, mode=0644) 
118   
119   
120 -def RemoveHostFromEtcHosts(hostname): 
121    """Wrapper around RemoveEtcHostsEntry. 
122   
123    @type hostname: str 
124    @param hostname: hostname that will be resolved and its 
125        full and shot name will be removed from 
126        L{constants.ETC_HOSTS} 
127   
128    """ 
129    RemoveEtcHostsEntry(constants.ETC_HOSTS, hostname) 
130    RemoveEtcHostsEntry(constants.ETC_HOSTS, hostname.split(".")[0]) 
131