hp_proliant_da_cntlr: do not discover phantom controllers

The controller table (cpqDaCntlrTable) on HPE ProLiant Gen11 / iLO 6 contains a
placeholder row -- typically index 0 -- whose condition, role, board status and
board condition cells are all '0', a value the vendor MIB does not define.
parse_hp_proliant_da_cntlr already parses such rows to None, but discovery
iterated over all section keys and still created a service for the phantom row,
which was then permanently UNKNOWN ('Controller not found in SNMP data').
Discovery now skips None entries.

Author: Bastian-Kuhn

cmk/plugins/hp_proliant/agent_based/hp_proliant_da_cntlr.py

@@ -187,8 +187,9 @@ def parse_hp_proliant_da_cntlr(string_table: StringTable) -> ParsedSection:
 
 
 def discovery_hp_proliant_da_cntlr(section: ParsedSection) -> DiscoveryResult:
-    if section:
-        yield from (Service(item=item) for item in section)
+    # Skip phantom placeholder rows (all-zero cells, parsed to ``None``): they
+    # are not real controllers and would produce a permanently UNKNOWN service.
+    yield from (Service(item=item) for item, data in section.items() if data is not None)
 
 
 def check_hp_proliant_da_cntlr(item: ControllerID, section: ParsedSection) -> CheckResult:

tests/unit/cmk/plugins/hp_proliant/agent_based/test_hp_proliant_da_cntlr.py

@@ -21,13 +21,14 @@
 
 
 def test_discovery() -> None:
+    # The all-zero placeholder row ("9") is a phantom controller and must not be
+    # discovered, otherwise its service is permanently UNKNOWN.
     assert list(
         discovery_hp_proliant_da_cntlr(section=parse_hp_proliant_da_cntlr(STRING_TABLE))
     ) == [
         Service(item="0"),
         Service(item="3"),
         Service(item="6"),
-        Service(item="9"),
     ]