Merge lp:~gnuoy/charm-helpers/os-release-no-cache into lp:charm-helpers

[Liam Young]

[lp:~gnuoy/charm-helpers/os-release-no-cache]

648. By Liam Young on 2016-10-10

Allow the module cached version of os_release to be bypassed. Useful when doing a charm upgrade and the os_release has changed since the module was imported

649. By Liam Young on 2016-10-10

Move reseting os_release cache out into a seperate function as per mp feedback

650. By Liam Young on 2016-10-10

Fix missing full stop from comment

[James Page (james-page)]

review: Approve

=== modified file 'charmhelpers/contrib/openstack/utils.py'
--- charmhelpers/contrib/openstack/utils.py	2016-10-07 15:20:20 +0000
+++ charmhelpers/contrib/openstack/utils.py	2016-10-10 12:03:38 +0000
@@ -410,14 +410,26 @@
 os_rel = None
 
 
-def os_release(package, base='essex'):
+def reset_os_release():
+    '''Unset the cached os_release version'''
+    global os_rel
+    os_rel = None
+
+
+def os_release(package, base='essex', reset_cache=False):
     '''
     Returns OpenStack release codename from a cached global.
+
+    If reset_cache then unset the cached os_release version and return the
+    freshly determined version.
+
     If the codename can not be determined from either an installed package or
     the installation source, the earliest release supported by the charm should
     be returned.
     '''
     global os_rel
+    if reset_cache:
+        reset_os_release()
     if os_rel:
         return os_rel
     os_rel = (git_os_codename_install_source(config('openstack-origin-git')) or

=== modified file 'tests/contrib/openstack/test_os_utils.py'
--- tests/contrib/openstack/test_os_utils.py	2015-11-03 12:19:54 +0000
+++ tests/contrib/openstack/test_os_utils.py	2016-10-10 12:03:38 +0000
@@ -110,3 +110,47 @@
             relation_id='neutron-plugin-api-subordinate:8',
             relation_settings={'restart-trigger': 'uuid4'}
         )
+
+    @mock.patch.object(utils, 'config')
+    @mock.patch('charmhelpers.contrib.openstack.utils.'
+                'git_os_codename_install_source')
+    @mock.patch('charmhelpers.contrib.openstack.utils.get_os_codename_package')
+    @mock.patch('charmhelpers.contrib.openstack.utils.'
+                'get_os_codename_install_source')
+    def test_os_release(self, mock_get_os_codename_install_source,
+                        mock_get_os_codename_package,
+                        mock_git_os_codename_install_source,
+                        mock_config):
+        # Wipe the modules cached os_rel
+        utils.os_rel = None
+        mock_get_os_codename_install_source.return_value = None
+        mock_get_os_codename_package.return_value = None
+        mock_git_os_codename_install_source.return_value = None
+        mock_config.return_value = 'cloud-pocket'
+        self.assertEqual(utils.os_release('my-pkg'), 'essex')
+        mock_get_os_codename_install_source.assert_called_once_with(
+            'cloud-pocket')
+        mock_get_os_codename_package.assert_called_once_with(
+            'my-pkg', fatal=False)
+        mock_git_os_codename_install_source.assert_called_once_with(
+            'cloud-pocket')
+        # Next call to os_release should pickup cached version
+        mock_get_os_codename_install_source.reset_mock()
+        mock_get_os_codename_package.reset_mock()
+        mock_git_os_codename_install_source.reset_mock()
+        self.assertEqual(utils.os_release('my-pkg'), 'essex')
+        self.assertFalse(mock_get_os_codename_install_source.called)
+        self.assertFalse(mock_get_os_codename_package.called)
+        self.assertFalse(mock_git_os_codename_install_source.called)
+        # Call os_release and bypass cache
+        mock_get_os_codename_install_source.reset_mock()
+        mock_get_os_codename_package.reset_mock()
+        mock_git_os_codename_install_source.reset_mock()
+        self.assertEqual(utils.os_release('my-pkg', reset_cache=True),
+                         'essex')
+        mock_get_os_codename_install_source.assert_called_once_with(
+            'cloud-pocket')
+        mock_get_os_codename_package.assert_called_once_with(
+            'my-pkg', fatal=False)
+        mock_git_os_codename_install_source.assert_called_once_with(
+            'cloud-pocket')