Use reset to fix cmdline

Reset is an application provided via ncurses which is useful in
resetting a terminal when things go wrong. Since podman is eating some
of the terminal output, it can leave the cmdline in a broken state at
the end of the undercloud install. We tried to address it outselves but
let's reuse an existing application instead. -I being passed to reset
skips the initialization strings which can erase the output.

Change-Id: Id9aa7910032588605977f4725385503cf0a235bc
Closes-Bug: #1833302

tripleoclient/tests/v1/tripleo/test_tripleo_deploy.py

@@ -887,7 +887,7 @@ class TestDeployUndercloud(TestPluginV1):
             env
         )
 
-    @mock.patch('tripleoclient.utils.send_cmdline_erase_sequence')
+    @mock.patch('tripleoclient.utils.reset_cmdline')
     @mock.patch('tripleoclient.v1.tripleo_deploy.Deploy.'
                 '_download_stack_outputs')
     @mock.patch('tripleo_common.actions.ansible.'
@@ -974,7 +974,7 @@ class TestDeployUndercloud(TestPluginV1):
         self.assertEqual(mock_killheat.call_count, 2)
         mock_cmdline.assert_called_once()
 
-    @mock.patch('tripleoclient.utils.send_cmdline_erase_sequence')
+    @mock.patch('tripleoclient.utils.reset_cmdline')
     @mock.patch('tripleoclient.utils.ansible_symlink')
     def test_take_action(self, mock_slink, mock_cmdline):
         mock_slink.side_effect = 'fake-cmd'
@@ -987,7 +987,7 @@ class TestDeployUndercloud(TestPluginV1):
                           self.cmd.take_action, parsed_args)
         mock_cmdline.assert_called_once()
 
-    @mock.patch('tripleoclient.utils.send_cmdline_erase_sequence')
+    @mock.patch('tripleoclient.utils.reset_cmdline')
     @mock.patch('tripleoclient.v1.tripleo_deploy.Deploy._standalone_deploy',
                 return_value=1)
     @mock.patch('tripleoclient.utils.ansible_symlink')

tripleoclient/utils.py

@@ -1929,8 +1929,10 @@ def check_deprecated_service_is_enabled(environment_files):
         check_file_for_enabled_service(env_file)
 
 
-def send_cmdline_erase_sequence():
-    # Send's an erase in line sequence to the output
-    # https://www.vt100.net/docs/vt100-ug/chapter3.html#EL
-    sys.stdout.write(u'\u001b[0K')
+def reset_cmdline():
+    """Run reset to cleanup cmdline"""
+    # only try to reset if stdout is a terminal, skip if not (e.g. CI)
+    if not sys.stdout.isatty():
+        return
+    sys.stdout.write(run_command(['reset', '-I']))
     sys.stdout.flush()

tripleoclient/v1/tripleo_deploy.py

@@ -1420,4 +1420,4 @@ class Deploy(command.Command):
         finally:
             # send erase sequence to reset the cmdline if paunch/ansible
             # mangled some escape sequences
-            utils.send_cmdline_erase_sequence()
+            utils.reset_cmdline()