Integrated version for #142

decouple.py

@@ -4,7 +4,7 @@
 import string
 from shlex import shlex
 from io import open
-from collections import OrderedDict
+from collections import ChainMap, OrderedDict
 
 # Useful for very coarse version differentiation.
 PYVERSION = sys.version_info
@@ -18,9 +18,9 @@
     text_type = unicode
 
 if PYVERSION >= (3, 2, 0):
-    read_config = lambda parser, file: parser.read_file(file)
+    def read_config(parser, file): return parser.read_file(file)
 else:
-    read_config = lambda parser, file: parser.readfp(file)
+    def read_config(parser, file): return parser.readfp(file)
 
 
 DEFAULT_ENCODING = 'UTF-8'
@@ -30,6 +30,7 @@
 TRUE_VALUES = {"y", "yes", "t", "true", "on", "1"}
 FALSE_VALUES = {"n", "no", "f", "false", "off", "0"}
 
+
 def strtobool(value):
     if isinstance(value, bool):
         return value
@@ -89,7 +90,8 @@ def get(self, option, default=undefined, cast=undefined):
             value = self.repository[option]
         else:
             if isinstance(default, Undefined):
-                raise UndefinedValueError('{} not found. Declare it as envvar or define a default value.'.format(option))
+                raise UndefinedValueError(
+                    '{} not found. Declare it as envvar or define a default value.'.format(option))
 
             value = default
 
@@ -144,6 +146,7 @@ class RepositoryEnv(RepositoryEmpty):
     """
     Retrieves option keys from .env files with fall back to os.environ.
     """
+
     def __init__(self, source, encoding=DEFAULT_ENCODING):
         self.data = {}
 
@@ -201,6 +204,7 @@ class AutoConfig(object):
     """
     SUPPORTED = OrderedDict([
         ('settings.ini', RepositoryIni),
+        ('settings.common.ini', RepositoryIni),
         ('.env', RepositoryEnv),
     ])
 
@@ -212,10 +216,13 @@ def __init__(self, search_path=None):
 
     def _find_file(self, path):
         # look for all files in the current path
+        filenames = []
         for configfile in self.SUPPORTED:
             filename = os.path.join(path, configfile)
             if os.path.isfile(filename):
-                return filename
+                filenames.append(filename)
+        if filenames:
+            return filenames
 
         # search the parent
         parent = os.path.dirname(path)
@@ -228,12 +235,16 @@ def _find_file(self, path):
     def _load(self, path):
         # Avoid unintended permission errors
         try:
-            filename = self._find_file(os.path.abspath(path))
+            filenames = self._find_file(os.path.abspath(path))
         except Exception:
-            filename = ''
-        Repository = self.SUPPORTED.get(os.path.basename(filename), RepositoryEmpty)
-
-        self.config = Config(Repository(filename, encoding=self.encoding))
+            filenames = ['']
+        chain = ChainMap()
+        for filename in filenames:
+            Repository = self.SUPPORTED.get(
+                os.path.basename(filename), RepositoryEmpty)
+            chain = chain.new_child(Repository(
+                filename, encoding=self.encoding))
+        self.config = Config(chain)
 
     def _caller_path(self):
         # MAGIC! Get the caller's module path.
@@ -254,6 +265,7 @@ def __call__(self, *args, **kwargs):
 
 # Helpers
 
+
 class Csv(object):
     """
     Produces a csv parser that return a list of transformed elements.
@@ -277,7 +289,7 @@ def __call__(self, value):
         if value is None:
             return self.post_process()
 
-        transform = lambda s: self.cast(s.strip(self.strip))
+        def transform(s): return self.cast(s.strip(self.strip))
 
         splitter = shlex(value, posix=True)
         splitter.whitespace = self.delimiter
@@ -310,7 +322,7 @@ def __call__(self, value):
         transform = self.cast(value)
         if transform not in self._valid_values:
             raise ValueError((
-                    'Value not in list: {!r}; valid values are {!r}'
-                ).format(value, self._valid_values))
+                'Value not in list: {!r}; valid values are {!r}'
+            ).format(value, self._valid_values))
         else:
             return transform