Add pfn2lfn function to the policy package

src/policy/CMSRucioPolicy/__init__.py

@@ -2,7 +2,7 @@
 #
 # Eric Vaandering <ewv@fnal.gov>, 2022
 
-from CMSRucioPolicy.algorithms import lfn2pfn, auto_approve
+from CMSRucioPolicy.algorithms import lfn2pfn, auto_approve, pfn2lfn
 
 SUPPORTED_VERSION = ["32", "33", "34"]
 
@@ -17,5 +17,8 @@ def get_algorithms():
         },
         'auto_approve': {
             'global': auto_approve.global_approval,
+        },
+        'pfn2lfn': {
+            'cms_pfn2lfn': pfn2lfn.cms_pfn2lfn,
         }
     }

src/policy/CMSRucioPolicy/algorithms/pfn2lfn.py

@@ -0,0 +1,14 @@
+"""
+PFN to scope:name translation algorithm for CMS Rucio policy
+"""
+from collections.abc import Mapping
+
+def cms_pfn2lfn(parsed_pfn: Mapping[str, str]) -> tuple[str, str]:
+    """
+    This function converts a PFN into scope:name pair.
+    It ignores user scopes and sets all scopes to cms.
+    """
+    # Ignore user scopes for now
+    scope = "cms"
+    name = parsed_pfn['path'] + parsed_pfn['name']
+    return name, scope