add system-wide IPython config

Mainly for use in multi-user administrated environments

- config files in `/usr[/local]/etc/ipython` will be loaded
- change priority config loading to load all found files in priority order
  instead of loading only the first found.

IPython/config/application.py

@@ -501,27 +501,32 b' class Application(SingletonConfigurable):'
 
         yield each config object in turn.
         """
-        pyloader = PyFileConfigLoader(basefilename+'.py', path=path, log=log)
-        jsonloader = JSONFileConfigLoader(basefilename+'.json', path=path, log=log)
-        config = None
-        for loader in [pyloader, jsonloader]:
-            try:
-                config = loader.load_config()
-            except ConfigFileNotFound:
-                pass
-            except Exception:
-                # try to get the full filename, but it will be empty in the
-                # unlikely event that the error raised before filefind finished
-                filename = loader.full_filename or basefilename
-                # problem while running the file
-                if log:
-                    log.error("Exception while loading config file %s",
-                            filename, exc_info=True)
-            else:
-                if log:
-                    log.debug("Loaded config file: %s", loader.full_filename)
-            if config:
-                 yield config
+        
+        if not isinstance(path, list):
+            path = [path]
+        for path in path[::-1]:
+            # path list is in descending priority order, so load files backwards:
+            pyloader = PyFileConfigLoader(basefilename+'.py', path=path, log=log)
+            jsonloader = JSONFileConfigLoader(basefilename+'.json', path=path, log=log)
+            config = None
+            for loader in [pyloader, jsonloader]:
+                try:
+                    config = loader.load_config()
+                except ConfigFileNotFound:
+                    pass
+                except Exception:
+                    # try to get the full filename, but it will be empty in the
+                    # unlikely event that the error raised before filefind finished
+                    filename = loader.full_filename or basefilename
+                    # problem while running the file
+                    if log:
+                        log.error("Exception while loading config file %s",
+                                filename, exc_info=True)
+                else:
+                    if log:
+                        log.debug("Loaded config file: %s", loader.full_filename)
+                if config:
+                     yield config
 
         raise StopIteration
 

IPython/config/tests/test_application.py

@@ -1,27 +1,18 b''
 # coding: utf-8
 """
 Tests for IPython.config.application.Application
-
-Authors:
-
-* Brian Granger
 """
 
-#-----------------------------------------------------------------------------
-#  Copyright (C) 2008-2011  The IPython Development Team
-#
-#  Distributed under the terms of the BSD License.  The full license is in
-#  the file COPYING, distributed as part of this software.
-#-----------------------------------------------------------------------------
-
-#-----------------------------------------------------------------------------
-# Imports
-#-----------------------------------------------------------------------------
+# Copyright (c) IPython Development Team.
+# Distributed under the terms of the Modified BSD License.
 
 import logging
+import os
 from io import StringIO
 from unittest import TestCase
 
+pjoin = os.path.join
+
 import nose.tools as nt
 
 from IPython.config.configurable import Configurable
@@ -31,13 +22,11 b' from IPython.config.application import ('
     Application
 )
 
+from IPython.utils.tempdir import TemporaryDirectory
 from IPython.utils.traitlets import (
     Bool, Unicode, Integer, List, Dict
 )
 
-#-----------------------------------------------------------------------------
-# Code
-#-----------------------------------------------------------------------------
 
 class Foo(Configurable):
 
@@ -189,5 +178,21 b' class TestApplication(TestCase):'
     def test_unicode_argv(self):
         app = MyApp()
         app.parse_command_line(['ünîcødé'])
-        
+    
+    def test_multi_file(self):
+        app = MyApp()
+        app.log = logging.getLogger()
+        name = 'config.py'
+        with TemporaryDirectory('_1') as td1:
+            with open(pjoin(td1, name), 'w') as f1:
+                f1.write("get_config().MyApp.Bar.b = 1")
+            with TemporaryDirectory('_2') as td2:
+                with open(pjoin(td2, name), 'w') as f2:
+                    f2.write("get_config().MyApp.Bar.b = 2")
+                app.load_config_file(name, path=[td2, td1])
+                app.init_bar()
+                self.assertEqual(app.bar.b, 2)
+                app.load_config_file(name, path=[td1, td2])
+                app.init_bar()
+                self.assertEqual(app.bar.b, 1)
 

IPython/core/application.py

@@ -7,25 +7,10 b' handling configuration and creating configurables.'
 
 The job of an :class:`Application` is to create the master configuration
 object and then create the configurable objects, passing the config to them.
-
-Authors:
-
-* Brian Granger
-* Fernando Perez
-* Min RK
-
 """
 
-#-----------------------------------------------------------------------------
-#  Copyright (C) 2008  The IPython Development Team
-#
-#  Distributed under the terms of the BSD License.  The full license is in
-#  the file COPYING, distributed as part of this software.
-#-----------------------------------------------------------------------------
-
-#-----------------------------------------------------------------------------
-# Imports
-#-----------------------------------------------------------------------------
+# Copyright (c) IPython Development Team.
+# Distributed under the terms of the Modified BSD License.
 
 import atexit
 import glob
@@ -42,15 +27,19 b' from IPython.utils.path import get_ipython_dir, get_ipython_package_dir, ensure_'
 from IPython.utils import py3compat
 from IPython.utils.traitlets import List, Unicode, Type, Bool, Dict, Set, Instance
 
-#-----------------------------------------------------------------------------
-# Classes and functions
-#-----------------------------------------------------------------------------
+if os.name == 'nt':
+    programdata = os.environ.get('PROGRAMDATA', None)
+    if programdata:
+        SYSTEM_CONFIG_DIRS = [pjoin(programdata, 'ipython')]
+    else:  # PROGRAMDATA is not defined by default on XP.
+        SYSTEM_CONFIG_DIRS = []
+else:
+    SYSTEM_CONFIG_DIRS = [
+        "/usr/local/etc/ipython",
+        "/etc/ipython",
+    ]
 
 
-#-----------------------------------------------------------------------------
-# Base Application Class
-#-----------------------------------------------------------------------------
-
 # aliases and flags
 
 base_aliases = {
@@ -100,7 +89,7 b' class BaseIPythonApplication(Application):'
     builtin_profile_dir = Unicode(
         os.path.join(get_ipython_package_dir(), u'config', u'profile', u'default')
     )
-
+    
     config_file_paths = List(Unicode)
     def _config_file_paths_default(self):
         return [py3compat.getcwd()]
@@ -336,6 +325,7 b' class BaseIPythonApplication(Application):'
 
     def init_config_files(self):
         """[optionally] copy default config files into profile dir."""
+        self.config_file_paths.extend(SYSTEM_CONFIG_DIRS)
         # copy config files
         path = self.builtin_profile_dir
         if self.copy_config_files: