Create a backup copy of the envs file.

quickstart/utils.py

Index: quickstart/utils.py
=== modified file 'quickstart/utils.py'
--- quickstart/utils.py	2014-01-09 11:22:54 +0000
+++ quickstart/utils.py	2014-01-10 15:30:49 +0000
@@ -24,6 +24,7 @@
 import collections
 import datetime
 import errno
+import functools
 import httplib
 import json
 import logging
@@ -326,6 +327,20 @@
     return parse_status_output(output, ['machines', '0', 'series'])
 
 
+def run_once(function):
+    """Return a decorated version of the given function which runs only once.
+
+    Subsequent runs are just ignored and return None.
+    """
+    @functools.wraps(function)
+    def decorated(*args, **kwargs):
+        if not decorated.called:
+            decorated.called = True
+            return function(*args, **kwargs)
+    decorated.called = False
+    return decorated
+
+
 def unit_changes(unit_name, changeset):
     """Parse the changeset and return the change related to the given unit.