Fixes import_modules_recursively for Windows

The neutron agents fail to start on Windows, due to the fact that
neutron.common.utils.import_modules_recursively expects the paths
to be forwardslash separated, while on Windows they are backslash
separated.

Change-Id: I5e15273c2f70b70fad0cf1216ef0b33c6a99d702
Closes-Bug: #1694220
(cherry picked from commit 572deac00b)

neutron/common/utils.py

@@ -23,6 +23,7 @@ import importlib
 import os
 import os.path
 import random
+import re
 import signal
 import sys
 import threading
@@ -60,6 +61,8 @@ SYNCHRONIZED_PREFIX = 'neutron-'
 
 DEFAULT_THROTTLER_VALUE = 2
 
+_SEPARATOR_REGEX = re.compile(r'[/\\]+')
+
 synchronized = lockutils.synchronized_with_prefix(SYNCHRONIZED_PREFIX)
 
 
@@ -871,6 +874,7 @@ def extract_exc_details(e):
 
 def import_modules_recursively(topdir):
     '''Import and return all modules below the topdir directory.'''
+    topdir = _SEPARATOR_REGEX.sub('/', topdir)
     modules = []
     for root, dirs, files in os.walk(topdir):
         for file_ in files:
@@ -881,7 +885,7 @@ def import_modules_recursively(topdir):
             if module == '__init__':
                 continue
 
-            import_base = root.replace('/', '.')
+            import_base = _SEPARATOR_REGEX.sub('.', root)
 
             # NOTE(ihrachys): in Python3, or when we are not located in the
             # directory containing neutron code, __file__ is absolute, so we

neutron/tests/unit/common/test_utils.py

@@ -14,8 +14,10 @@
 
 import os.path
 import random
+import re
 import sys
 
+import ddt
 import eventlet
 import mock
 import netaddr
@@ -804,17 +806,20 @@ class TestExcDetails(base.BaseTestCase):
             utils.extract_exc_details(Exception()), six.text_type)
 
 
+@ddt.ddt
 class ImportModulesRecursivelyTestCase(base.BaseTestCase):
 
-    def test_recursion(self):
+    @ddt.data('/', r'\\')
+    def test_recursion(self, separator):
         expected_modules = (
             'neutron.tests.unit.tests.example.dir.example_module',
             'neutron.tests.unit.tests.example.dir.subdir.example_module',
         )
         for module in expected_modules:
             sys.modules.pop(module, None)
-        modules = utils.import_modules_recursively(
-            os.path.dirname(tests.__file__))
+
+        topdir = re.sub(r'[/\\]+', separator, os.path.dirname(tests.__file__))
+        modules = utils.import_modules_recursively(topdir)
         for module in expected_modules:
             self.assertIn(module, modules)
             self.assertIn(module, sys.modules)