fix rendering resolv.conf if no 'options' are provided

this makes some changes to the cc_resolv_conf to make its
generate_resolv_conf method more easily callable (for future test).

Also sets it up so that 'options' is always defined when the template
is rendered.

LP: #1328953

3 files changed, 20 insertions, 12 deletions

diff --git a/ChangeLog b/ChangeLog
index 4d8d6427..4d326b31 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -21,6 +21,7 @@
    are generated. [Jordan Evans] (LP: #1333920)
  - default settings: fix typo resulting in OpenStack and GCE not working
    unless config explicitly provided (LP: #1329583) [Garrett Holmstrom])
+ - fix rendering resolv.conf if no 'options' are provided (LP: #1328953)
 0.7.5:
  - open 0.7.5
  - Add a debug log message around import failures
diff --git a/cloudinit/config/cc_resolv_conf.py b/cloudinit/config/cc_resolv_conf.py
index 879b62b1..bbaa6c63 100644
--- a/cloudinit/config/cc_resolv_conf.py
+++ b/cloudinit/config/cc_resolv_conf.py
@@ -49,23 +49,22 @@
 #
 
 
+from cloudinit import log as logging
 from cloudinit.settings import PER_INSTANCE
 from cloudinit import templater
 from cloudinit import util
 
+LOG = logging.getLogger(__name__)
+
 frequency = PER_INSTANCE
 
 distros = ['fedora', 'rhel', 'sles']
 
 
-def generate_resolv_conf(cloud, log, params):
-    template_fn = cloud.get_template_filename('resolv.conf')
-    if not template_fn:
-        log.warn("No template found, not rendering /etc/resolv.conf")
-        return
-
+def generate_resolv_conf(template_fn, params, target_fname="/etc/resolv.conf"):
     flags = []
     false_flags = []
+
     if 'options' in params:
         for key, val in params['options'].iteritems():
             if type(val) == bool:
@@ -77,12 +76,15 @@ def generate_resolv_conf(cloud, log, params):
     for flag in flags + false_flags:
         del params['options'][flag]
 
+    if not params.get('options'):
+        params['options'] = {}
+
     params['flags'] = flags
-    log.debug("Writing resolv.conf from template %s" % template_fn)
-    templater.render_to_file(template_fn, '/etc/resolv.conf', params)
+    LOG.debug("Writing resolv.conf from template %s" % template_fn)
+    templater.render_to_file(template_fn, target_fname, params)
 
 
-def handle(name, cfg, _cloud, log, _args):
+def handle(name, cfg, cloud, log, _args):
     """
     Handler for resolv.conf
 
@@ -102,8 +104,13 @@ def handle(name, cfg, _cloud, log, _args):
                    " 'manage_resolv_conf' present but set to False"), name)
         return
 
-    if not "resolv_conf" in cfg:
+    if "resolv_conf" not in cfg:
         log.warn("manage_resolv_conf True but no parameters provided!")
 
-    generate_resolv_conf(_cloud, log, cfg["resolv_conf"])
+    template_fn = cloud.get_template_filename('resolv.conf')
+    if not template_fn:
+        log.warn("No template found, not rendering /etc/resolv.conf")
+        return
+
+    generate_resolv_conf(template_fn=template_fn, params=cfg["resolv_conf"])
     return
diff --git a/templates/resolv.conf.tmpl b/templates/resolv.conf.tmpl
index 6f908f30..1300156c 100644
--- a/templates/resolv.conf.tmpl
+++ b/templates/resolv.conf.tmpl
@@ -21,7 +21,7 @@ domain {{domain}}
 
 sortlist {% for sort in sortlist %}{{sort}} {% endfor %}
 {% endif %}
-{% if options is defined or flags is defined %}
+{% if options or flags %}
 
 options {% for flag in flags %}{{flag}} {% endfor %}
 {% for key, value in options.iteritems() -%}