use constants for startswith in handlers. add strip_prefix_suffix.

Just cleans up some repeated strings into module constants + a util function to
do the boothook prefix cleanup (before writing).

1 files changed, 8 insertions, 0 deletions

diff --git a/cloudinit/util.py b/cloudinit/util.py
index c45aae06..47d71ef4 100644
--- a/cloudinit/util.py
+++ b/cloudinit/util.py
@@ -1530,6 +1530,14 @@ def shellify(cmdlist, add_header=True):
     return content
 
 
+def strip_prefix_suffix(line, prefix=None, suffix=None):
+    if prefix and line.startswith(prefix):
+        line = line[len(prefix):]
+    if suffix and line.endswith(suffix):
+        line = line[:-len(suffix)]
+    return line
+
+
 def is_container():
     """
     Checks to see if this code running in a container of some sort