review: Use regex in rfc1123 helper

src/profiles_management/helpers/k8s.py

@@ -1,6 +1,7 @@
 """Generic helpers for manipulating K8s objects, via lightkube."""
 
 import logging
+import re
 
 import tenacity
 from lightkube import Client
@@ -68,21 +69,15 @@ def to_rfc1123_compliant(name: str) -> str:
     Returns:
         The RFC 1123-compliant string.
     """
-    compliant_str = name.lower()
-    compliant_str = "".join(char if char.isalnum() else "-" for char in compliant_str)
+    if len(name) == 0:
+        raise ValueError("Can't convert to valid RFC1123 an empty string.")
 
-    # remove starting non-alphanum chars
-    i = 0
-    while not compliant_str[i].isalnum():
-        i += 1
-    compliant_str = compliant_str[i:63]
+    compliant_str = name.lower()
+    compliant_str = re.sub(r"[^a-z0-9-]", "-", compliant_str)
 
-    # remove ending non-alphanum chars
-    j = len(compliant_str)
-    while not compliant_str[j - 1].isalnum():
-        j -= 1
+    compliant_str = compliant_str.lstrip("-").rstrip("-")
 
-    return compliant_str[:j]
+    return compliant_str[:63]
 
 
 @tenacity.retry(stop=tenacity.stop_after_delay(300), wait=tenacity.wait_fixed(5), reraise=True)

tests/unit/profiles-management/helpers/test_k8s.py

@@ -18,14 +18,20 @@ def test_no_annotations():
     assert get_annotations(resource) == {}
 
 
-def test_non_alphanum_to_hyphen():
+def test_rfc1123_non_alphanum_to_hyphen():
     name = "[email protected]"
 
     assert to_rfc1123_compliant(name) == "kimonas-canonical-com"
 
 
-def test_more_than_63_char_name():
+def test_rfc1123_more_than_63_char_name():
     name = "I-had-to-think-of-a-reeeally-long-string-to-use-for-the-test-which-was-tough"
 
     assert len(name) > 63
     assert len(to_rfc1123_compliant(name)) == 63
+
+
+def test_rfc1123_strip_starting_and_trailing_dashes():
+    name = "-=shouldn't have trailing dashes!"
+
+    assert to_rfc1123_compliant(name) == "shouldn-t-have-trailing-dashes"