NullPointerException in the Profiling plugin (xpack.profiling.action.CO2Calculator.getKiloWattsPerCore)

[rockdaboot]

Elasticsearch Version

8.15 snapshot, 8.14

Installed Plugins

No response

Java Version

bundled

OS Version

any

Problem Description

The Kibana flamegraph and TopN functions view in Universal Profiling stay empty, even though data exists.
The reason for this is a Null Pointer Exception in the profiling plugin caused by incomplete host metadata.

Relevant part of the stacktrace:

[2024-06-19T18:37:03,104][WARN ][r.suppressed             ] [runTask-0] path: /_profiling/topn/functions, params: {}, status: 500 java.lang.NullPointerException: Cannot invoke "String.hashCode()" because "<local2>" is null
        at org.elasticsearch.xpack.profiling.action.CO2Calculator.getKiloWattsPerCore(CO2Calculator.java:59)
        at org.elasticsearch.xpack.profiling.action.CO2Calculator.getAnnualCO2Tons(CO2Calculator.java:54)
        at org.elasticsearch.xpack.profiling.action.TransportGetStackTracesAction$StackTraceHandler.calculateCO2AndCosts(TransportGetStackTracesAction.java:631)
        at org.elasticsearch.xpack.profiling.action.TransportGetStackTracesAction$StackTraceHandler.mayFinish(TransportGetStackTracesAction.java:645)
        at org.elasticsearch.xpack.profiling.action.TransportGetStackTracesAction$StackTraceHandler.onHostsResponse(TransportGetStackTracesAction.java:601)

Steps to Reproduce

Use Universal Profiling in Kibana with incomplete entries in profiling-hosts.

Logs (if relevant)

No response

[elasticsearchmachine]

Pinging @elastic/obs-knowledge-team (Team:obs-knowledge)

[rockdaboot]

An example record from profiling-hosts that triggers this NPE:

    "_source": {
      "profiling.project.id": "",
      "host.id": "",
      "@timestamp": 0,
      "ecs.version": "1.12.0"
    }