Merge "cfg,generator: add Opt.sample_default attribute"

3 files changed, 48 insertions, 4 deletions

diff --git a/oslo/config/cfg.py b/oslo/config/cfg.py
index 8c6d749..ca90c4c 100644
--- a/oslo/config/cfg.py
+++ b/oslo/config/cfg.py
@@ -594,6 +594,8 @@ class Opt(object):
         a single character CLI option name
       default:
         the default value of the option
+      sample_default:
+        a sample default value string to include in sample config files
       positional:
         True if the option is a positional CLI argument
       metavar:
@@ -607,7 +609,7 @@ class Opt(object):
                  default=None, positional=False, metavar=None, help=None,
                  secret=False, required=False,
                  deprecated_name=None, deprecated_group=None,
-                 deprecated_opts=None):
+                 deprecated_opts=None, sample_default=None):
         """Construct an Opt object.
 
         The only required parameter is the option's name. However, it is
@@ -627,6 +629,7 @@ class Opt(object):
         :param deprecated_name: deprecated name option.  Acts like an alias
         :param deprecated_group: the group containing a deprecated alias
         :param deprecated_opts: array of DeprecatedOpt(s)
+        :param sample_default: a default string for sample config files
         """
         if name.startswith('_'):
             raise ValueError('illegal name %s with prefix _' % (name,))
@@ -645,6 +648,7 @@ class Opt(object):
             self.dest = dest
         self.short = short
         self.default = default
+        self.sample_default = sample_default
         self.positional = positional
         self.metavar = metavar
         self.help = help
diff --git a/oslo/config/generator.py b/oslo/config/generator.py
index 46d21c1..5e8e9ef 100644
--- a/oslo/config/generator.py
+++ b/oslo/config/generator.py
@@ -96,7 +96,13 @@ The default runtime values of configuration options are not always the most
 suitable values to include in sample config files - for example, rather than
 including the IP address or hostname of the machine where the config file
 was generated, you might want to include something like '10.0.0.1'. To
-facilitate this, applications can supply their own 'sanitizer' function via
+facilitate this, options can be supplied with a 'sample_default' attribute::
+
+  cfg.StrOpt('base_dir'
+             default=os.getcwd(),
+             sample_default='/usr/lib/myapp')
+
+Alternatively, applications can supply their own 'sanitizer' function via
 the 'oslo.config.sanitizer' entry point namespace. For example::
 
     def sanitize_default(self, opt, default_str):
@@ -208,12 +214,16 @@ class _OptFormatter(object):
                          (d.group or 'DEFAULT', d.name or opt.dest))
 
         if isinstance(opt, cfg.MultiStrOpt):
-            if opt.default is None:
+            if opt.sample_default is not None:
+                defaults = opt.sample_default
+            elif opt.default is None:
                 defaults = ['<None>']
             else:
                 defaults = opt.default
         else:
-            if opt.default is None:
+            if opt.sample_default is not None:
+                default_str = str(opt.sample_default)
+            elif opt.default is None:
                 default_str = '<None>'
             elif isinstance(opt, cfg.StrOpt):
                 default_str = opt.default
diff --git a/tests/test_generator.py b/tests/test_generator.py
index 3275408..a126933 100644
--- a/tests/test_generator.py
+++ b/tests/test_generator.py
@@ -61,6 +61,9 @@ class GeneratorTestCase(base.BaseTestCase):
         'str_opt': cfg.StrOpt('str_opt',
                               default='foo bar',
                               help='a string'),
+        'str_opt_sample_default': cfg.StrOpt('str_opt',
+                                             default='fooishbar',
+                                             help='a string'),
         'str_opt_with_space': cfg.StrOpt('str_opt',
                                          default='  foo bar  ',
                                          help='a string with spaces'),
@@ -82,6 +85,10 @@ class GeneratorTestCase(base.BaseTestCase):
         'multi_opt': cfg.MultiStrOpt('multi_opt',
                                      default=['1', '2', '3'],
                                      help='multiple strings'),
+        'multi_opt_sample_default': cfg.MultiStrOpt('multi_opt',
+                                                    default=['1', '2', '3'],
+                                                    sample_default=['5', '6'],
+                                                    help='multiple strings'),
     }
 
     content_scenarios = [
@@ -401,6 +408,29 @@ class GeneratorTestCase(base.BaseTestCase):
 #multi_opt = 2
 #multi_opt = 3
 ''')),
+        ('str_opt_sample_default',
+         dict(opts=[('test', [(None, [opts['str_opt_sample_default']])])],
+              expected='''[DEFAULT]
+
+#
+# From test
+#
+
+# a string (string value)
+#str_opt = fooishbar
+''')),
+        ('multi_opt_sample_default',
+         dict(opts=[('test', [(None, [opts['multi_opt_sample_default']])])],
+              expected='''[DEFAULT]
+
+#
+# From test
+#
+
+# multiple strings (multi valued)
+#multi_opt = 5
+#multi_opt = 6
+''')),
         ('sanitizer',
          dict(opts=[('test', [(None, [opts['str_opt']])])],
               sanitizer=lambda o, s: s.replace(' ', 'ish'),