Fix HostnameMap lookup - replace str_replace with yaql

Using str_replace when looking up hostnames in
HostnameMap may return unpredictable results.
For example if the map contain:

HostnameMap:
  overcloud-compute-12: cmp-12-london
  overcloud-compute-123: cmp-123-berlin

When we do string replace for a hostname that is
not in the map (example: 'overcloud-compute-124')
it will match on the substring. The result would
be 'cmp-12-london4'.

This change replaces the str_replace with a yaql
expression that will return the value of they key
matching the hostname provided. If the key is not
in the map, the hostname is returned.

Closes-Bug: #1781560
Change-Id: Ia3a6a3539cd566131cd81b4d755190aa5b61a573

puppet/role.role.j2.yaml

@@ -360,9 +360,11 @@ resources:
       user_data_format: SOFTWARE_CONFIG
       user_data: {get_resource: UserData}
       name:
-        str_replace:
-            template: {get_param: Hostname}
-            params: {get_param: HostnameMap}
+        yaql:
+          expression: $.data.hostname_map.get($.data.hostname, $.data.hostname)
+          data:
+            hostname: {get_param: Hostname}
+            hostname_map: {get_param: HostnameMap}
       software_config_transport: {get_param: SoftwareConfigTransport}
       metadata:
         map_merge:

releasenotes/notes/fix-str-replace-hostname-issue-393fb6954f12f7e6.yaml

@@ -0,0 +1,10 @@
+---
+fixes:
+  - |
+    Fixes an issue where Custom Hostnames is in use. Previously it was possible
+    that the ``HostnameMap`` lookup lookup would return unexpected and
+    incorrect results if the hostname (the key) is not in the map. The string
+    replacement mechanism used previously was replaced by a yaql expression
+    that will do exact matching only. If no matching key is in the
+    HostnameMap, the default hostname is returned.
+    `bug 1781560  <https://review.openstack.org/#/c/582475/>`_.