The plugin sets the [`source_host`](https://github.com/logstash-plugins/logstash-filter-metrics/issues/60) field name, which should be updated to `[host][name]` in ECS mode. Also, the plugin does not use the codec for decoding, [the JSON codec](https://github.com/logstash-plugins/logstash-input-gelf/blob/v3.3.0/lib/logstash/inputs/gelf.rb#L248-L254) might be a good fit to gain `event.original` as well as `target` support.
The plugin sets the
source_hostfield name, which should be updated to[host][name]in ECS mode.Also, the plugin does not use the codec for decoding, the JSON codec might be a good fit to gain
event.originalas well astargetsupport.