Make recipe module loader non-recursive

recipe_engine/loader.py

 # Copyright 2016 The LUCI Authors. All rights reserved.
 # Use of this source code is governed under the Apache License, Version 2.0
 # that can be found in the LICENSE file.
 
 import collections
 import imp
 import inspect
 import os
 import sys
 
@@ skipping 327 matching lines @@
   fullname = '%s.%s.%s' % (
       RECIPE_MODULE_PREFIX, universe_view.package.name, modname)
   mod = _find_and_load_module(fullname, modname, path)
 
   # This actually loads the dependencies.
   mod.LOADED_DEPS = universe_view.deps_from_spec(getattr(mod, 'DEPS', []))
 
   # Prevent any modules that mess with sys.path from leaking.
   with env.temp_sys_path():
     sys.modules['%s.DEPS' % fullname] = mod.LOADED_DEPS
-    _recursive_import(
-        path, '%s.%s' % (RECIPE_MODULE_PREFIX, universe_view.package.name))
+    _load_recipe_module_files(path, mod, fullname)
     _patchup_module(modname, mod, universe_view)
 
   return mod
 
 
-def _recursive_import(path, prefix):
-  modname = os.path.splitext(os.path.basename(path))[0]
-  fullname = '%s.%s' % (prefix, modname)
-  mod = _find_and_load_module(fullname, modname, path)
-  if not os.path.isdir(path):
-    return mod
+def _load_recipe_module_files(path, mod, prefix):
+  for subitem in os.listdir(path):
+    if subitem in ('api.py', 'test_api.py') or subitem.endswith('config.py'):
+      subpath = os.path.join(path, subitem)
+      subname = os.path.splitext(subitem)[0]
+      fullname = '%s.%s' % (prefix, subname)
+      submod = _find_and_load_module(fullname, subname, subpath)
 
-  for subitem in os.listdir(path):
-    subpath = os.path.join(path, subitem)
-    subname = os.path.splitext(subitem)[0]
-    if os.path.isdir(subpath):
-      if not os.path.exists(os.path.join(subpath, '__init__.py')):
-        continue
-    elif not subpath.endswith('.py') or subitem.startswith('__init__.py'):
-      continue
-
-    submod = _recursive_import(subpath, fullname)
-
-    if not hasattr(mod, subname):
-      setattr(mod, subname, submod)
-    else:
-      prev = getattr(mod, subname)
-      assert submod is prev, (
-        'Conflicting modules: %s and %s' % (prev, mod))
-
-  return mod
+      if not hasattr(mod, subname):
+        setattr(mod, subname, submod)
+      else:
+        prev = getattr(mod, subname)
+        assert submod is prev, (
+          'Conflicting modules: %s and %s' % (prev, mod))
 
 
 def _patchup_module(name, submod, universe_view):
   """Finds framework related classes and functions in a |submod| and adds
   them to |submod| as top level constants with well known names such as
   API, CONFIG_CTX, TEST_API, and PROPERTIES.
 
   |submod| is a recipe module (akin to python package) with submodules such as
   'api', 'config', 'test_api'. This function scans through dicts of that
   submodules to find subclasses of RecipeApi, RecipeTestApi, etc.
@@ skipping 241 matching lines @@
   for k,v in toplevel_deps.iteritems():
     setattr(api, k, mapper.instantiate(v))
   return api
 
 
 def _resolve_requirement(req, engine):
   if req._typ == 'client':
     return engine._get_client(req._name)
   else:
     raise ValueError('Unknown requirement type [%s]' % (req._typ,))