[tor-commits] [stem/master] Adding a @uses_settings to our config module

[atagar at torproject.org]

commit fb65766f1e74cf3218efa9889a5479a13ba70ca4
Author: Damian Johnson <atagar at torproject.org>
Date:   Fri Apr 18 10:29:22 2014 -0700

    Adding a @uses_settings to our config module
    
    The @uses_settings helper our interpretor panel uses is actually a nice way of
    taking advantage of our config module. Moving the helper to our util so others
    can use it.
---
 stem/interpretor/__init__.py |   48 +++++++-----------------------------------
 stem/util/conf.py            |   44 ++++++++++++++++++++++++++++++++++++++
 2 files changed, 52 insertions(+), 40 deletions(-)

diff --git a/stem/interpretor/__init__.py b/stem/interpretor/__init__.py
index f1da5d9..93e4e6a 100644
--- a/stem/interpretor/__init__.py
+++ b/stem/interpretor/__init__.py
@@ -26,6 +26,14 @@ from stem.util.term import RESET, Attr, Color, format
 
 PROMPT = format(">>> ", Color.GREEN, Attr.BOLD) + RESET * 10
 
+settings_path = os.path.join(os.path.dirname(__file__), 'settings.cfg')
+uses_settings = stem.util.conf.uses_settings('stem_interpretor', settings_path)
+
+
+ at uses_settings
+def msg(config, message, **attr):
+  return config.get(message).format(**attr)
+
 
 def main():
   import readline
@@ -70,43 +78,3 @@ def main():
       except (KeyboardInterrupt, EOFError, stem.SocketClosed) as exc:
         print  # move cursor to the following line
         break
-
-
-def uses_settings(func):
-  """
-  Loads our interpretor's internal settings. This should be treated as a fatal
-  failure if unsuccessful.
-
-  :raises: **IOError** if we're unable to read or parse our internal
-    configurations
-  """
-
-  config = stem.util.conf.get_config('stem_interpretor')
-
-  if not config.get('settings_loaded', False):
-    settings_path = os.path.join(os.path.dirname(__file__), 'settings.cfg')
-    config.load(settings_path)
-    config.set('settings_loaded', 'true')
-
-  return func
-
-
- at uses_settings
-def msg(message, **attr):
-  """
-  Provides the given message.
-
-  :param str message: message handle
-  :param dict attr: values to insert into the message
-
-  :returns: **str** that was requested
-
-  :raises: **ValueError** if string key doesn't exist
-  """
-
-  config = stem.util.conf.get_config('stem_interpretor')
-
-  try:
-    return config.get(message).format(**attr)
-  except:
-    raise ValueError('We attempted to use an undefined string resource (%s)' % message)
diff --git a/stem/util/conf.py b/stem/util/conf.py
index c11adf2..3f753f0 100644
--- a/stem/util/conf.py
+++ b/stem/util/conf.py
@@ -141,6 +141,7 @@ Here's an expanation of what happened...
 
   config_dict - provides a dictionary that's kept in sync with our config
   get_config - singleton for getting configurations
+  uses_settings - provides an annotation for functions that use configurations
   parse_enum_csv - helper funcion for parsing confguration entries for enums
 
   Config - Custom configuration
@@ -156,6 +157,7 @@ Here's an expanation of what happened...
     +- get_value - provides the value for a given key as a string
 """
 
+import functools
 import threading
 
 from stem.util import log
@@ -233,6 +235,48 @@ def get_config(handle):
   return CONFS[handle]
 
 
+def uses_settings(handle, path, lazy_load = True):
+  """
+  Provides a function that can be used as an annotation for other functions
+  that require settings to be loaded. Functions with this annotation will be
+  provided with the configuration as its first argument.
+
+  ::
+
+    uses_settings = stem.util.conf.uses_settings('my_app', '/path/to/settings.cfg')
+
+    @uses_settings
+    def my_function(config):
+      print 'hello %s!' % config.get('username', '')
+
+  :param str handle: hande for the configuration
+  :param str path: path where the configuration should be loaded from
+  :param bool lazy_load: loads the configuration file when the annotation is
+    used if true, otherwise it's loaded right away
+
+  :returns: **function** that can be used as an annotation to provide the
+    configuration
+
+  :raises: **IOError** if we fail to read the configuration file, if
+    **lazy_load** is true then this arises when we use the annotation
+  """
+
+  config = get_config(handle)
+
+  if not lazy_load and not config.get('settings_loaded', False):
+    config.load(path)
+    config.set('settings_loaded', 'true')
+
+  def annotation(func):
+    if lazy_load and not config.get('settings_loaded', False):
+      config.load(path)
+      config.set('settings_loaded', 'true')
+
+    return functools.partial(func, config)
+
+  return annotation
+
+
 def parse_enum(key, value, enumeration):
   """
   Provides the enumeration value for a given key. This is a case insensitive