# HG changeset patch
# User Philippe Pepiot <philippe.pepiot@logilab.fr>
# Date 1466087132 -7200
# Node ID b6f6737d4823d8aa55b1d01b5a83cb0815ac0bf3
# Parent  308ac9def79f2db7e64036e27320657af6568340
wsgi: clearer exception when CW_INSTANCE is missing

instance_name is mandatory for cwcfg.config_for()

Raise with a KeyError: 'CW_INSTANCE' instead of hard to read exception.

diff -r 308ac9def79f -r b6f6737d4823 pyramid_cubicweb/__init__.py
--- a/pyramid_cubicweb/__init__.py	Fri Jun 03 17:58:43 2016 +0200
+++ b/pyramid_cubicweb/__init__.py	Thu Jun 16 16:25:32 2016 +0200
@@ -136,7 +136,7 @@
 
     """
     if instance_name is None:
-        instance_name = os.environ.get('CW_INSTANCE')
+        instance_name = os.environ['CW_INSTANCE']
     if debug is None:
         debug = 'CW_DEBUG' in os.environ