in_systemd support lowercase option for field names #1543
Description
The fluentd-systemd plugin has an option for fields_lowercase to make all the fields from systemd lowercase, instead of the default where everything is uppercase. It would be nice if fluent-bit supported this option as well, where the fields would get mapped to the lowercase equivalent (i.e. _PID => _pid, MESSAGE => message).
I've tried several options on the fluentd side, and none of them have worked.
https://github.com/JonathanSerafini/fluent-plugin-mutate_filter
- Only allows mutating the value to lowercase, not the key
https://github.com/shunwen/fluent-plugin-rename-key
- Only allows re/moving the matched group, not any mutations such as \L
https://docs.fluentd.org/filter/record_transformer
- Would require creating a new record with the same contents and key, but lower case key, then have a separate plugin to remove the old key.
This issue could likely be fixed with modifications to the first two plugins, but it would be nice if this was supported as a built-in option to the systemd plugin in fluent-bit.