some refactor of settings manager (without changing API): don't fail if no settings module is found (fail on scrapy.cmdline instead). also, some code improvements for clarity.

scrapy/command/cmdline.py

@@ -8,7 +8,7 @@ import cProfile
 import scrapy
 from scrapy import log
 from scrapy.spider import spiders
-from scrapy.conf import settings
+from scrapy.conf import settings, SETTINGS_MODULE
 
 def find_commands(dir):
     try:
@@ -88,6 +88,10 @@ def command_settings(cmdname):
 command_executed = {}
 
 def execute():
+    if not settings.settings_module:
+        print "Scrapy %s\n" % scrapy.__version__
+        print "Error: Cannot find %r module in python path." % SETTINGS_MODULE
+        sys.exit(1)
     execute_with_args(sys.argv)
 
 def execute_with_args(argv):
@@ -113,7 +117,7 @@ def execute_with_args(argv):
         print "Scrapy %s\n" % scrapy.__version__
         print "Unknown command: %s\n" % cmdname
         print 'Type "%s -h" for help' % argv[0]
-        sys.exit()
+        sys.exit(2)
 
     (opts, args) = parser.parse_args(args=argv[1:])
     del args[0]  # args[0] is cmdname

scrapy/conf/__init__.py

@@ -1,3 +1,9 @@
+"""
+Scrapy settings manager
+
+See documentation in docs/topics/settings.rst
+"""
+
 import os
 import cPickle as pickle
 
@@ -5,42 +11,37 @@ SETTINGS_MODULE = os.environ.get('SCRAPYSETTINGS_MODULE', 'scrapy_settings')
 SETTINGS_DISABLED = os.environ.get('SCRAPY_SETTINGS_DISABLED', False)
 
 class Settings(object):
-    """Class to obtain configuration values from settings module
-       which can be overriden by environment variables prepended by SCRAPY_"""
 
     # settings in precedence order
     overrides = None
-    settings = None
+    settings_module = None
     defaults = None
     global_defaults = None
 
     def __init__(self):
         pickled_settings = os.environ.get("SCRAPY_PICKLED_SETTINGS_TO_OVERRIDE")
         self.overrides = pickle.loads(pickled_settings) if pickled_settings else {}
-        if not SETTINGS_DISABLED:
-            self.settings = self._import(SETTINGS_MODULE)
+        self.settings_module = self._import(SETTINGS_MODULE)
         self.defaults = {}
         self.global_defaults = self._import('scrapy.conf.default_settings')
 
     def _import(self, modulepath):
-        return __import__(modulepath, {}, {}, [''])
+        try:
+            return __import__(modulepath, {}, {}, [''])
+        except ImportError:
+            pass
 
     def __getitem__(self, opt_name):
         if not SETTINGS_DISABLED:
             if opt_name in self.overrides:
                 return self.overrides[opt_name]
-
             if 'SCRAPY_' + opt_name in os.environ:
                 return os.environ['SCRAPY_' + opt_name]
-
-            if hasattr(self.settings, opt_name):
-                return getattr(self.settings, opt_name)
-
+            if hasattr(self.settings_module, opt_name):
+                return getattr(self.settings_module, opt_name)
             if opt_name in self.defaults:
                 return self.defaults[opt_name]
-
-        if hasattr(self.global_defaults, opt_name):
-            return getattr(self.global_defaults, opt_name)
+        return getattr(self.global_defaults, opt_name, None)
 
     def get(self, name, default=None):
         return self[name] if self[name] is not None else default