Added utils.py that contains a normalize_dnsname function good for sorting dns names to a human readable list.

bin/ohi

@@ -12,12 +12,15 @@ import subprocess
 import ConfigParser
 
 from openshift_ansible import awsutil
+from openshift_ansible import utils
 from openshift_ansible.awsutil import ArgumentError
 
 CONFIG_MAIN_SECTION = 'main'
 CONFIG_HOST_TYPE_ALIAS_SECTION = 'host_type_aliases'
 CONFIG_INVENTORY_OPTION = 'inventory'
 
+
+
 class Ohi(object):
     def __init__(self):
         self.inventory = None
@@ -60,7 +63,7 @@ class Ohi(object):
             # We weren't able to determine what they wanted to do
             raise ArgumentError("Invalid combination of arguments")
 
-        for host in hosts:
+        for host in sorted(hosts, key=utils.normalize_dnsname):
             print host
         return 0
 

bin/openshift_ansible/utils.py

@@ -0,0 +1,30 @@
+#!/usr/bin/env python
+# vim: expandtab:tabstop=4:shiftwidth=4
+
+''' The purpose of this module is to contain small utility functions.
+'''
+
+import re
+
+def normalize_dnsname(name, padding=10):
+    ''' The purpose of this function is to return a dns name with zero padding,
+        so that it sorts properly (as a human would expect).
+
+        Example: name=ex-lrg-node10.prod.rhcloud.com
+        Returns: ex-lrg-node0000000010.prod.rhcloud.com
+
+        Example Usage:
+            sorted(['a3.example.com', 'a10.example.com', 'a1.example.com'],
+                   key=normalize_dnsname)
+
+        Returns: ['a1.example.com', 'a3.example.com', 'a10.example.com']
+    '''
+    parts = re.split(r'(\d+)', name)
+    retval = []
+    for part in parts:
+        if re.match(r'^\d+$', part):
+            retval.append(part.zfill(padding))
+        else:
+            retval.append(part)
+
+    return ''.join(retval)