Ensure we don't have any trailing "requires" for paunch units

It might happen people want to disable the health checks in an update.
This change will ensure paunch cleans things up before (re)creating the
main service unit file, in order to avoid failed dependencies in systemd
configuration.

Change-Id: Ia8ebe35a9edc41f3ec635cc05dde08783c5e2a44

paunch/tests/test_utils_systemd.py

@@ -23,9 +23,12 @@
 
 class TestUtilsSystemd(base.TestCase):
 
+    @mock.patch('shutil.rmtree', autospec=True)
+    @mock.patch('os.path.exists', autospec=True)
     @mock.patch('subprocess.check_call', autospec=True)
     @mock.patch('os.chmod')
-    def test_service_create(self, mock_chmod, mock_subprocess_check_call):
+    def test_service_create(self, mock_chmod, mock_subprocess_check_call,
+                            mock_exists, mock_rmtree):
         container = 'my_app'
         service = 'tripleo_' + container
         cconfig = {'depends_on': ['something'], 'restart': 'unless-stopped',
@@ -46,6 +49,10 @@ def test_service_create(self, mock_chmod, mock_subprocess_check_call):
             mock.call(['systemctl', 'enable', '--now', service]),
         ])
 
+        mock_rmtree.assert_has_calls([
+            mock.call(sysd_unit_f + '.requires')
+        ])
+
         os.rmdir(tempdir)
 
     @mock.patch('subprocess.check_call', autospec=True)

paunch/utils/systemd.py

@@ -72,6 +72,11 @@ def service_create(container, cconfig, sysdir=constants.SYSTEMD_DIR, log=None):
         'stop_grace_period': stop_grace_period,
         'sys_exec': '\n'.join(['%s=%s' % (x, y) for x, y in sys_exec.items()]),
     }
+    # Ensure we don't have some trailing .requires directory and content for
+    # this service
+    if os.path.exists(sysd_unit_f + '.requires'):
+        shutil.rmtree(sysd_unit_f + '.requires')
+
     with open(sysd_unit_f, 'w') as unit_file:
         os.chmod(unit_file.name, 0o644)
         unit_file.write("""[Unit]