Make lockutils main() a console entry point

This is more lib-ish than calling python -m on the module.

As part of this change, I also improved the unit tests for this code.
Before we weren't unsetting OSLO_LOCK_PATH before calling the main
function, so we had no way of knowing if it was being set correctly.

I also added a test case to verify return value propagation and
removed a private method that was never called.

Change-Id: I6c35b5409bf567767c5c71b9041dd7f7a012255d

oslo/concurrency/lockutils.py

@@ -332,11 +332,14 @@ def synchronized_with_prefix(lock_file_prefix):
     return functools.partial(synchronized, lock_file_prefix=lock_file_prefix)
 
 
-def main(argv):
+def lock_wrapper(argv):
     """Create a dir for locks and pass it to command from arguments
 
+    This is exposed as a console script entry point named
+    oslo-concurrency-lock-wrapper
+
     If you run this:
-    python -m openstack.common.lockutils python setup.py testr <etc>
+        oslo-concurrency-lock-wrapper python setup.py testr <etc>
 
     a temporary directory will be created for all your locks and passed to all
     your tests in an environment variable. The temporary dir will be deleted
@@ -352,5 +355,5 @@ def main(argv):
     return ret_val
 
 
-if __name__ == '__main__':
+def main():
-    sys.exit(main(sys.argv))
+    sys.exit(lock_wrapper(sys.argv))

setup.cfg

@@ -29,6 +29,8 @@ namespace_packages =
 [entry_points]
 oslo.config.opts =
     oslo.concurrency = oslo.concurrency.opts:list_opts
+console_scripts =
+    lockutils-wrapper = oslo.concurrency.lockutils:main
 
 [build_sphinx]
 source-dir = doc/source

tests/unit/test_lockutils.py

@@ -22,10 +22,8 @@ import tempfile
 import threading
 import time
 
-from oslo.config import cfg
 from oslotest import base as test_base
 import six
-from six import moves
 
 from oslo.concurrency.fixture import lockutils as fixtures
 from oslo.concurrency import lockutils
@@ -454,23 +452,14 @@ class LockutilsModuleTestCase(test_base.BaseTestCase):
     def setUp(self):
         super(LockutilsModuleTestCase, self).setUp()
         self.old_env = os.environ.get('OSLO_LOCK_PATH')
+        if self.old_env is not None:
+            del os.environ['OSLO_LOCK_PATH']
 
     def tearDown(self):
-        if self.old_env is None:
+        if self.old_env is not None:
-            del os.environ['OSLO_LOCK_PATH']
-        else:
             os.environ['OSLO_LOCK_PATH'] = self.old_env
         super(LockutilsModuleTestCase, self).tearDown()
 
-    def _lock_path_conf_test(self, lock_dir):
-        cfg.CONF.unregister_opts(lockutils.util_opts)
-        lockutils_ = moves.reload_module(lockutils)
-        with lockutils_.lock('test-lock', external=True):
-            if not os.path.exists(lock_dir):
-                os._exit(2)
-            if not os.path.exists(os.path.join(lock_dir, 'test-lock')):
-                os._exit(3)
-
     def test_main(self):
         script = '\n'.join([
             'import os',
@@ -479,9 +468,18 @@ class LockutilsModuleTestCase(test_base.BaseTestCase):
             'assert os.path.isdir(lock_path)',
         ])
         argv = ['', sys.executable, '-c', script]
-        retval = lockutils.main(argv)
+        retval = lockutils.lock_wrapper(argv)
         self.assertEqual(retval, 0, "Bad OSLO_LOCK_PATH has been set")
 
+    def test_return_value_maintained(self):
+        script = '\n'.join([
+            'import sys',
+            'sys.exit(1)',
+        ])
+        argv = ['', sys.executable, '-c', script]
+        retval = lockutils.lock_wrapper(argv)
+        self.assertEqual(retval, 1)
+
 
 class TestLockFixture(test_base.BaseTestCase):
 

tox.ini

@@ -15,19 +15,19 @@ setenv =
 deps = -r{toxinidir}/requirements.txt
        -r{toxinidir}/test-requirements.txt
 commands =
-    python -m oslo.concurrency.lockutils python setup.py testr --slowest --testr-args='{posargs}'
+    lockutils-wrapper python setup.py testr --slowest --testr-args='{posargs}'
 
 [testenv:py33]
 deps = -r{toxinidir}/requirements-py3.txt
        -r{toxinidir}/test-requirements.txt
 commands =
-    python -m oslo.concurrency.lockutils python -m testtools.run tests.unit.test_lockutils
+    lockutils-wrapper python -m testtools.run tests.unit.test_lockutils
 
 [testenv:py34]
 deps = -r{toxinidir}/requirements-py3.txt
        -r{toxinidir}/test-requirements.txt
 commands =
-    python -m oslo.concurrency.lockutils python -m testtools.run tests.unit.test_lockutils
+    lockutils-wrapper python -m testtools.run tests.unit.test_lockutils
 
 [testenv:pep8]
 commands = flake8