Error logging is insufficient to track down cause of error

[robbavey]

When using the geoip filter with a custom database, the current error handling is insufficient to be able to track down the cause of the issue, as it masks the original cause of the error, and does not print a stack trace to determine where the original exception was thrown from:

[2025-04-28T15:50:26,757][DEBUG][org.logstash.filters.geoip.GeoIPFilter][main] GeoIP2 Exception. exception=org.logstash.filters.geoip.GeoIPFilter$GeoIp2InvalidCustomFieldException: invalid custom field, field=[source][ip], event=2025-04-25T14:41:00.000Z {hostname=Robs-MacBook-Pro.local} %{message}

This error message is insufficient in a number of different ways:

• The event is not logged correctly, only showing up as %{message}
• Invalid custom field can originate from a number of different areas in the code.
• The cause exception message is lost
• The cause exception stack trace is lost.