- Interpolation variables now try to use the registry first, but fall

  back to "stack" values; the most important of where is ``%(here)s``;
  this interpolation variable can be used in any config file.  It will
  be the absolute path to the parent directory of the configuration
  file in which it was declared.  Any stack variable can be overridden
  (for interpolation purposes) by a registry variable.

CHANGES.txt

@@ -1,6 +1,16 @@
 repoze.configuration Changelog
 ==============================
 
+Next release
+------------
+
+- Interpolation variables now try to use the registry first, but fall
+  back to "stack" values; the most important of where is ``%(here)s``;
+  this interpolation variable can be used in any config file.  It will
+  be the absolute path to the parent directory of the configuration
+  file in which it was declared.  Any stack variable can be overridden
+  (for interpolation purposes) by a registry variable.
+
 0.4 (2009-07-25)
 ----------------
 

repoze/configuration/context.py

@@ -21,9 +21,11 @@ def __init__(self, registry, loader=None):
     def interpolate(self, value):
         def _interpolation_replace(match):
             s = match.group(1)
-            if not s in self.registry:
-                raise KeyError(s)
-            return self.registry[s]
+            if s in self.registry:
+                return self.registry[s]
+            if self.stack and s in self.stack[-1]:
+                return self.stack[-1][s]
+            raise KeyError(s)
         if '%(' in value:
             value = _INTERP.sub(_interpolation_replace, value)
         return value.encode('utf-8')
@@ -73,11 +75,23 @@ def stream(self, filename, package=None):
             return open(filename)
         else:
             return pkg_resources.resource_stream(package.__name__, filename)
+
+    def abs_filename(self, filename, package=None):
+        if os.path.isabs(filename):
+            return filename
+        if package is None:
+            package = self.current_package()
+        if package is None:
+            return os.path.abspath(filename)
+        else:
+            return pkg_resources.resource_filename(package.__name__, filename)
 
     def load(self, filename, package, override=False, loader=None):
+        fn = self.abs_filename(filename, package)
+        here = os.path.dirname(fn)
         stream = self.stream(filename, package)
         self.stack.append({'filename':filename, 'package':package,
-                           'override':override})
+                           'override':override, 'here':here})
         if loader is None:
             loader = self.loader
         try:

repoze/configuration/tests/test_context.py

@@ -18,12 +18,26 @@ def test_ctor(self):
         self.assertEqual(context.stack, [])
         self.assertEqual(context.actions, [])
 
-    def test_interpolate(self):
+    def test_interpolate_from_registry(self):
         registry = {'here':'/here', 'there':'/there'}
         context = self._makeOne(registry)
         result = context.interpolate('Here is %(here)s, there is %(there)s')
         self.assertEqual(result, 'Here is /here, there is /there')
 
+    def test_interpolate_from_registry_overrides_stack(self):
+        registry = {'here':'/here', 'there':'/there'}
+        context = self._makeOne(registry)
+        context.stack = [{'here':'stack_here', 'there':'stack_there'}]
+        result = context.interpolate('Here is %(here)s, there is %(there)s')
+        self.assertEqual(result, 'Here is /here, there is /there')
+
+    def test_interpolate_from_registry_falls_back_to_stack(self):
+        registry = {'here':'/here'}
+        context = self._makeOne(registry)
+        context.stack = [{'here':'stack_here', 'there':'stack_there'}]
+        result = context.interpolate('Here is %(here)s, there is %(there)s')
+        self.assertEqual(result, 'Here is /here, there is stack_there')
+
     def test_interpolate_nothing_to_interpolate(self):
         registry = {'here':'/here', 'there':'/there'}
         context = self._makeOne(registry)
@@ -180,6 +194,38 @@ def test_stream_nopackage_currentpackage(self):
         expected = open(filename).read()
         self.assertEqual(context.stream('__init__.py').read(), expected)
 
+    def test_abs_filename_absolute(self):
+        import os
+        from repoze.configuration.tests import fixtures
+        filename = os.path.join(os.path.dirname(
+            os.path.abspath(fixtures.__file__)), '__init__.py')
+        context = self._makeOne()
+        result = context.abs_filename(filename)
+        self.assertEqual(result, filename)
+
+    def test_abs_filename_nopackage_nocurrentpackage(self):
+        import os
+        from repoze.configuration.tests import fixtures
+        old_cwd = os.getcwd()
+        fixtures = os.path.dirname(os.path.abspath(fixtures.__file__))
+        filename = os.path.join(fixtures, '__init__.py')
+        try:
+            os.chdir(fixtures)
+            context = self._makeOne()
+            result = context.abs_filename('__init__.py')
+            self.assertEqual(result, filename)
+        finally:
+            os.chdir(old_cwd)
+
+    def test_abs_filename_nopackage_currentpackage(self):
+        import os
+        from repoze.configuration.tests import fixtures
+        context = self._makeOne()
+        context.stack.append({'package':fixtures})
+        fixtures = os.path.dirname(os.path.abspath(fixtures.__file__))
+        filename = os.path.join(fixtures, '__init__.py')
+        self.assertEqual(context.abs_filename('__init__.py'), filename)
+
     def test_load_standard_loader(self):
         def loader(context, stream):
             context.loaded = True
@@ -197,9 +243,23 @@ def loader(context, stream):
         context.load('configure.yml', fixtures, loader=loader)
         self.assertEqual(context.stack, [])
         self.assertEqual(context.loaded, True)
-
         # doesn't blow up
-
+
+    def test_load_sets_stack(self):
+        import os
+        result = []
+        def loader(context, stream):
+            result.append(context.stack[-1])
+        context = self._makeOne()
+        from repoze.configuration.tests import fixtures
+        context.stack = [{'package':fixtures}]
+        context.load('configure.yml', fixtures, loader=loader)
+        result = result[0]
+        expect_here = os.path.dirname(os.path.abspath(fixtures.__file__))
+        self.assertEqual(result['here'], expect_here)
+        self.assertEqual(result['override'], False)
+        self.assertEqual(result['filename'], 'configure.yml')
+        self.assertEqual(result['package'], fixtures)
 
     def test_execute(self):
         registry = {}