From 2be70492beb7212fdc585601c9e9939be6803acd Mon Sep 17 00:00:00 2001
From: kali <kali@leap.se>
Date: Wed, 29 Aug 2012 04:50:17 +0900
Subject: spec creation moved to JSONLeapConfig __metaclass__

now we expect spec to be a dict for all the JSONLeapConfig instances.
---
 src/leap/base/config.py | 50 ++++++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 49 insertions(+), 1 deletion(-)

(limited to 'src/leap/base/config.py')

diff --git a/src/leap/base/config.py b/src/leap/base/config.py
index 93a89638..1ced471b 100644
--- a/src/leap/base/config.py
+++ b/src/leap/base/config.py
@@ -1,7 +1,6 @@
 """
 Configuration Base Class
 """
-import configuration  # python configuration module, not local!
 import grp
 import json
 import logging
@@ -12,6 +11,8 @@ import os
 logger = logging.getLogger(name=__name__)
 logger.setLevel('DEBUG')
 
+import configuration
+
 from leap.base import exceptions
 from leap.base import constants
 from leap.util.fileutil import (mkdir_p)
@@ -45,8 +46,54 @@ class BaseLeapConfig(object):
         raise NotImplementedError("abstract base class")
 
 
+class MetaConfigWithSpec(type):
+    """
+    metaclass for JSONLeapConfig classes.
+    It creates a configuration spec out of
+    the `spec` dictionary.
+    """
+    # XXX in the near future, this is the
+    # place where we want to enforce
+    # singletons, read-only and stuff.
+    def __new__(meta, classname, bases, classDict):
+        spec_options = classDict.get('spec', None)
+        # XXX if not spec_options, raise BadConfiguration or something
+        # we create a configuration spec attribute from the spec dict
+        config_class = type(
+            classname + "Spec",
+            (configuration.Configuration, object),
+            {'options': spec_options})
+        classDict['spec'] = config_class
+
+        return type.__new__(meta, classname, bases, classDict)
+
+##########################################################
+# hacking in progress:
+
+# Configs have:
+# - a slug (from where a filename/folder is derived)
+# - a spec (for validation and defaults).
+#   this spec is basically a dict that will be used
+#   for type casting and validation, and defaults settings.
+
+# all config objects, since they are derived from  BaseConfig, implement basic
+# useful methods:
+# - save
+# - load
+# - get_config (returns a optparse.OptionParser object)
+
+# TODO:
+# - have a good type cast repertory (uris, version, hashes...)
+# - raise validation errors
+# - multilingual objects
+
+##########################################################
+
+
 class JSONLeapConfig(BaseLeapConfig):
 
+    __metaclass__ = MetaConfigWithSpec
+
     def __init__(self, *args, **kwargs):
         # sanity check
         assert self.slug is not None
@@ -94,6 +141,7 @@ class JSONLeapConfig(BaseLeapConfig):
         config_file = get_config_file(filename, folder)
         return config_file
 
+
 #
 # utility functions
 #
-- 
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