Calculate a suitable column width for positional arguments

Overwrite the method add_arguments in the class
OpenStackHelpFormatter to calculate a suitable columnt width
(max_help_position) for the positional arguments.

example output before this patch:

    alarm-threshold-create
                        Create a new alarm based on computed statistics.
    alarm-threshold-update
                        Update an existing alarm based on computed statistics.
    alarm-update        Update an existing alarm (Deprecated).

example output after this patch:

    alarm-threshold-create    Create a new alarm based on computed statistics.
    alarm-threshold-update    Update an existing alarm based on computed
                              statistics.
    alarm-update              Update an existing alarm (Deprecated).

Change-Id: I945e46bb9e0309b960e3322261d9d6ff9fa35b52
Closes-Bug: #1326471

1 files changed, 12 insertions, 0 deletions

diff --git a/ceilometerclient/shell.py b/ceilometerclient/shell.py
index 46a460c..baf31a1 100644
--- a/ceilometerclient/shell.py
+++ b/ceilometerclient/shell.py
@@ -396,6 +396,18 @@ class CeilometerShell(object):
 
 
 class HelpFormatter(argparse.HelpFormatter):
+    INDENT_BEFORE_ARGUMENTS = 6
+    MAX_WIDTH_ARGUMENTS = 32
+
+    def add_arguments(self, actions):
+        for action in filter(lambda x: not x.option_strings, actions):
+            for choice in action.choices:
+                length = len(choice) + self.INDENT_BEFORE_ARGUMENTS
+                if(length > self._max_help_position and
+                   length <= self.MAX_WIDTH_ARGUMENTS):
+                    self._max_help_position = length
+        super(HelpFormatter, self).add_arguments(actions)
+
     def start_section(self, heading):
         # Title-case the headings
         heading = '%s%s' % (heading[0].upper(), heading[1:])