Switch to oslo_utils.importutils to load module

The imp module is deprecated since a while and the load_source
method has been removed from docs because broken [1][2].
Switch to oslo_utils.importutils for the same.

[1] https://bugs.python.org/issue14551
[2] https://mail.python.org/pipermail/python-ideas/2014-December/030265.html

Change-Id: Ic567e48b925befe2c196a5d46de8e504f273387e

tacker/api/extensions.py

@@ -15,11 +15,11 @@
 #    under the License.
 
 import abc
-import imp
 import os
 
 from oslo_config import cfg
 from oslo_log import log as logging
+from oslo_utils import importutils
 import routes
 import six
 import webob.dec
@@ -540,7 +540,8 @@ class ExtensionManager(object):
                 mod_name, file_ext = os.path.splitext(os.path.split(f)[-1])
                 ext_path = os.path.join(path, f)
                 if file_ext.lower() == '.py' and not mod_name.startswith('_'):
-                    mod = imp.load_source(mod_name, ext_path)
+                    mod = importutils.import_module(
+                        'tacker.extensions.' + mod_name)
                     ext_name = mod_name[0].upper() + mod_name[1:]
                     new_ext_class = getattr(mod, ext_name, None)
                     if not new_ext_class:

tools/check_i18n.py

@@ -15,10 +15,11 @@
 from __future__ import print_function
 
 import compiler
-import imp
 import os.path
 import sys
 
+from olso_utils import importutils
+
 
 def is_localized(node):
     """Check message wrapped by _()"""
@@ -116,9 +117,8 @@ def check_i18n(input_file, i18n_msg_predicates, msg_format_checkers, debug):
 
 if __name__ == '__main__':
     input_path = sys.argv[1]
-    cfg_path = sys.argv[2]
     try:
-        cfg_mod = imp.load_source('', cfg_path)
+        cfg_mod = importutils.import_module(tools.check_i18n)
     except Exception:
         print("Load cfg module failed", file=sys.stderr)
         sys.exit(1)
@@ -128,8 +128,8 @@ if __name__ == '__main__':
     black_list = cfg_mod.file_black_list
 
     debug = False
-    if len(sys.argv) > 3:
-        if sys.argv[3] == '-d':
+    if len(sys.argv) > 2:
+        if sys.argv[2] == '-d':
             debug = True
 
     if os.path.isfile(input_path):

tox.ini

@@ -54,7 +54,7 @@ commands =
 whitelist_externals = bash
 
 [testenv:i18n]
-commands = python ./tools/check_i18n.py ./tacker ./tools/i18n_cfg.py
+commands = python ./tools/check_i18n.py ./tacker
 
 [testenv:docs]
 deps = -r{toxinidir}/doc/requirements.txt