cloud-init/cloudinit/CloudConfig/cc_update_etc_hosts.py
Scott Moser c582ac7729 fix incorrect logic when 'manage_etc_hosts' has a value
For better or worse, 'manage_etc_hosts' means 
   "write /etc/hosts from the template"

The default setting is 'False', which was not to update
/etc/hosts at all.  Now, we're updating /etc/hosts, claiming
the 127.0.1.1 entry as owned by cloud-init if manage_etc_hosts is
false.
2011-08-03 14:41:41 -04:00

81 lines
2.9 KiB
Python

# vi: ts=4 expandtab
#
# Copyright (C) 2011 Canonical Ltd.
#
# Author: Scott Moser <scott.moser@canonical.com>
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License version 3, as
# published by the Free Software Foundation.
#
# 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, see <http://www.gnu.org/licenses/>.
import cloudinit.util as util
from cloudinit.CloudConfig import per_always
import StringIO
frequency = per_always
def handle(name,cfg,cloud,log,args):
( hostname, fqdn ) = util.get_hostname_fqdn(cfg, cloud)
use_template = util.get_cfg_option_bool(cfg,"manage_etc_hosts", False)
if not use_template:
# manage_etc_hosts not true, update the 127.0.1.1 entry via update_etc_hosts
log.debug("manage_etc_hosts is not set, checking sanity of /etc/hosts")
update_etc_hosts(hostname, fqdn, log)
return
# manage_etc_hosts is set, render from template file
try:
if not hostname:
log.info("manage_etc_hosts was set, but no hostname found")
return
util.render_to_file('hosts', '/etc/hosts', \
{ 'hostname' : hostname, 'fqdn' : fqdn })
except Exception as e:
log.warn("failed to update /etc/hosts")
raise
def update_etc_hosts(hostname, fqdn, log):
with open('/etc/hosts', 'r') as etchosts:
header = "# Added by cloud-init\n"
hosts_line = "127.0.1.1\t%s %s\n" % (fqdn, hostname)
need_write = False
need_change = True
new_etchosts = StringIO.StringIO()
for line in etchosts:
split_line = [s.strip() for s in line.split()]
if len(split_line) < 2:
new_etchosts.write(line)
continue
if line == header:
continue
ip, hosts = split_line[0], split_line[1:]
if ip == "127.0.1.1":
if sorted([hostname, fqdn]) == sorted(hosts):
need_change = False
if need_change == True:
line = "%s%s" % (header, hosts_line)
need_change = False
need_write = True
new_etchosts.write(line)
etchosts.close()
if need_change == True:
new_etchosts.write("%s%s" % (header, hosts_line))
need_write = True
if need_write == True:
new_etcfile = open ('/etc/hosts','wb')
new_etcfile.write(new_etchosts.getvalue())
new_etcfile.close()
new_etchosts.close()
return