Improve piggyback processing performance

A call to get_piggybacked_hosts_time_settings with a given piggybacked_hostname
processed all piggyback data needlessly, leading to a huge performance
impact.

This change propagates the piggybacked_hostname further to reduce the
overhead in the called helpers.

We'll have to see if this is enough. If not, we will need to make more
drastic changes ;).

CMK-21777

Change-Id: I78d72f13518c65acdba72b99cab0c7ec38d3cb23

cmk/base/config.py

@@ -3951,7 +3951,9 @@ def get_clustered_service_configuration(
     def get_piggybacked_hosts_time_settings(
         self, piggybacked_hostname: HostName | None = None
     ) -> Sequence[tuple[str | None, str, int]]:
-        all_sources = piggyback_backend.get_piggybacked_host_with_sources(cmk.utils.paths.omd_root)
+        all_sources = piggyback_backend.get_piggybacked_host_with_sources(
+            cmk.utils.paths.omd_root, piggybacked_hostname
+        )
         used_sources = (
             {m.source for sources in all_sources.values() for m in sources}
             if piggybacked_hostname is None

cmk/piggyback/backend/_storage.py

@@ -152,12 +152,16 @@ def get_messages_for(
 
 
 def get_piggybacked_host_with_sources(
-    omd_root: Path,
+    omd_root: Path, piggybacked_hostname: HostName | None = None
 ) -> Mapping[HostAddress, Sequence[PiggybackMetaData]]:
     """Generates all piggyback pig/piggybacked host pairs"""
     return {
         piggybacked_host: _get_payload_meta_data(piggybacked_host, omd_root)
-        for piggybacked_host_folder in _get_piggybacked_host_folders(omd_root)
+        for piggybacked_host_folder in (
+            [d for d in [payload_dir(omd_root) / piggybacked_hostname] if d.exists()]
+            if piggybacked_hostname
+            else _get_piggybacked_host_folders(omd_root)
+        )
         if (piggybacked_host := HostAddress(piggybacked_host_folder.name))
     }