Processor scripting language support

[sandervandegeijn]

Is your feature request related to a problem? Please describe.
Some other logforwarders support flexible scripting, i.e. Fluent-bit supports Lua as an option to perform more complex operations than the pipeline might support. This would enable the user to build complex handling and extend the processing capabilities. We have used this to do more complex conditional logic.

Describe the solution you'd like
Lua/Javascript/whatever language would be really nice to be able to use. It needs to be performant and needs to fit the data prepper architecture.

Describe alternatives you've considered (Optional)
Using fluent-bit itself - but I have found it less reliable than data prepper or logstash in some circumstances.

Additional context
None