Get Azure endpoint server from DHCP client

It is more efficient and cross-distribution safe to use the hooks function
from dhclient to obtain the Azure endpoint server (DHCP option 245).

This is done by providing shell scritps that are called by the hooks
infrastructure of both dhclient and NetworkManager.  The hooks then
invoke 'cloud-init dhclient-hook' that maintains json data
with the dhclient options in
/run/cloud-init/dhclient.hooks/<interface>.json .

The azure helper then pulls the value from
/run/cloud-init/dhclient.hooks/<interface>.json file(s). If that file does
not exist or the value is not present, it will then fall back to the
original method of scraping the dhcp client lease file.

1 files changed, 27 insertions, 18 deletions

diff --git a/cloudinit/cmd/main.py b/cloudinit/cmd/main.py
index 63621c1d..ba22b168 100644
--- a/cloudinit/cmd/main.py
+++ b/cloudinit/cmd/main.py
@@ -25,7 +25,6 @@ import argparse
 import json
 import os
 import sys
-import tempfile
 import time
 import traceback
 
@@ -47,6 +46,10 @@ from cloudinit.reporting import events
 from cloudinit.settings import (PER_INSTANCE, PER_ALWAYS, PER_ONCE,
                                 CLOUD_CONFIG)
 
+from cloudinit.atomic_helper import atomic_write_json
+
+from cloudinit.dhclient_hook import LogDhclient
+
 
 # Pretty little cheetah formatted welcome message template
 WELCOME_MSG_TPL = ("Cloud-init v. ${version} running '${action}' at "
@@ -452,22 +455,10 @@ def main_single(name, args):
         return 0
 
 
-def atomic_write_file(path, content, mode='w'):
-    tf = None
-    try:
-        tf = tempfile.NamedTemporaryFile(dir=os.path.dirname(path),
-                                         delete=False, mode=mode)
-        tf.write(content)
-        tf.close()
-        os.rename(tf.name, path)
-    except Exception as e:
-        if tf is not None:
-            os.unlink(tf.name)
-        raise e
-
-
-def atomic_write_json(path, data):
-    return atomic_write_file(path, json.dumps(data, indent=1) + "\n")
+def dhclient_hook(name, args):
+    record = LogDhclient(args)
+    record.check_hooks_dir()
+    record.record()
 
 
 def status_wrapper(name, args, data_d=None, link_d=None):
@@ -627,7 +618,6 @@ def main(sysv_args=None):
     # This subcommand allows you to run a single module
     parser_single = subparsers.add_parser('single',
                                           help=('run a single module '))
-    parser_single.set_defaults(action=('single', main_single))
     parser_single.add_argument("--name", '-n', action="store",
                                help="module name to run",
                                required=True)
@@ -644,6 +634,16 @@ def main(sysv_args=None):
                                      ' pass to this module'))
     parser_single.set_defaults(action=('single', main_single))
 
+    parser_dhclient = subparsers.add_parser('dhclient-hook',
+                                            help=('run the dhclient hook'
+                                                  'to record network info'))
+    parser_dhclient.add_argument("net_action",
+                                 help=('action taken on the interface'))
+    parser_dhclient.add_argument("net_interface",
+                                 help=('the network interface being acted'
+                                       ' upon'))
+    parser_dhclient.set_defaults(action=('dhclient_hook', dhclient_hook))
+
     args = parser.parse_args(args=sysv_args)
 
     try:
@@ -677,9 +677,18 @@ def main(sysv_args=None):
                         "running single module %s" % args.name)
         report_on = args.report
 
+    elif name == 'dhclient_hook':
+        rname, rdesc = ("dhclient-hook",
+                        "running dhclient-hook module")
+
     args.reporter = events.ReportEventStack(
         rname, rdesc, reporting_enabled=report_on)
+
     with args.reporter:
         return util.log_time(
             logfunc=LOG.debug, msg="cloud-init mode '%s'" % name,
             get_uptime=True, func=functor, args=(name, args))
+
+
+if __name__ == '__main__':
+    main(sys.argv)