Sanitize provided ARL templates

ARL templates are extracted from environment variable which can in
practice easily include some trailing whitespace characters. Unstripped
ARLs with trailing whitechars are not accepted by the FastPurge API
resulting in 4xx errors.

tests/test_cdn.py

@@ -105,7 +105,12 @@ def test_publisher_with_cache_purge(pulp, requests_mock):
             "clean": True,
         },
         "cdn_root": "https://cdn.example.com",
-        "arl_templates": ["/arl/1/test/{ttl}/{path}", "/arl/2/test/{ttl}/{path}"],
+        "arl_templates": [
+            "/arl/1/test/{ttl}/{path}",
+            "/arl/2/test/{ttl}/{path}",
+            # extra case with whitespace chars
+            "  /arl/3/test/{ttl}/{path} /extra// \n\n  \t  ",
+        ],
         "max_retry_sleep": 0.001,
     }
     setup_fastpurge_mock(requests_mock)
@@ -137,6 +142,7 @@ def test_publisher_with_cache_purge(pulp, requests_mock):
         "https://cdn.example.com/content/unit/1/client/repomd.xml",
         "/arl/1/test/33s/content/unit/1/client/repomd.xml",
         "/arl/2/test/33s/content/unit/1/client/repomd.xml",
+        "/arl/3/test/33s/content/unit/1/client/repomd.xml /extra//",
     ]
 
 

ubipop/_cdn.py

@@ -180,7 +180,7 @@ def __init__(self, url, arl_templates=None, max_retry_sleep=_MAX_SLEEP, **kwargs
                 used within this class (e.g. "verify", "cert").
         """
         self._url = url
-        self._arl_templates = arl_templates
+        self._arl_templates = [item.strip() for item in arl_templates if item]
         self._tls = threading.local()
 
         retry_args = {