Sync 'validations/library/ini.py' with the validations framework

Ibd1e54b2d2748b3bf8d2c1cabad3a9faf832e9b2 introduced a new "default"
parameter to the "ini" module allowing to return a success (with a
default value) even if the key isn't found in the file.

This patch also synchronizes the ctlplane-ip-range validation in the
validations directory.

Change-Id: I5e3fd6286c8f65586416b75472678bacfa5a4cd6
Signed-off-by: Gael Chamoulaud <gchamoul@redhat.com>

validations/ctlplane-ip-range.yaml

@@ -24,6 +24,7 @@
       section: ctlplane-subnet
       key: dhcp_start
       ignore_missing_file: True
+      default: "192.0.2.5"
     register: dhcp_start
 
   - name: Get dhcp_end value from the undercloud.conf file
@@ -33,10 +34,11 @@
       section: ctlplane-subnet
       key: dhcp_end
       ignore_missing_file: True
+      default: "192.0.2.24"
     register: dhcp_end
 
   - name: Check the size of the DHCP range for overcloud nodes
     ip_range:
-      start: "{{ dhcp_start.value|default('192.0.2.5', true) }}"
-      end: "{{ dhcp_end.value|default('192.0.2.24', true) }}"
+      start: "{{ dhcp_start.value }}"
+      end: "{{ dhcp_end.value }}"
       min_size: "{{ ctlplane_iprange_min_size }}"

validations/library/ini.py

@@ -52,7 +52,7 @@ def check_file(path, ignore_missing):
         return ''
 
 
-def get_result(path, section, key):
+def get_result(path, section, key, default=None):
     '''Get value based on section and key'''
 
     msg = ''
@@ -73,10 +73,16 @@ def get_result(path, section, key):
         ret = ReturnValue.OK
         return (ret, msg, value)
     except ConfigParser.Error:
-        value = None
-        msg = "There is no key '{}' under the section '{}' in file {}.".format(
-              key, section, path)
-        ret = ReturnValue.KEY_NOT_FOUND
+        if default:
+            msg = ("There is no key '{}' under section '{}' in file {}. Using"
+                   " default value '{}'".format(key, section, path, default))
+            ret = ReturnValue.OK
+            value = default
+        else:
+            value = None
+            msg = "There is no key '{}' under the section '{}' in file {}.".format(
+                  key, section, path)
+            ret = ReturnValue.KEY_NOT_FOUND
         return (ret, msg, value)
 
 
@@ -102,6 +108,10 @@ options:
         description:
             - Section key to look up
         type: str
+    default:
+        required: false
+        description:
+            - Default value if key isn't found
     ignore_missing_file:
         required: false
         description:
@@ -142,8 +152,9 @@ def main():
         # Try to parse the result from ini file
         section = module.params.get('section')
         key = module.params.get('key')
+        default = module.params.get('default')
 
-        ret, msg, value = get_result(ini_file_path, section, key)
+        ret, msg, value = get_result(ini_file_path, section, key, default)
 
         if ret == ReturnValue.INVALID_FORMAT:
             module.fail_json(msg=msg)