Dynamic interpolation of variables

[dotansimha]

Not sure where this needs to be implemented. As we might want to allow users to easily do mapping of headers, and other request parameters.

I was thinking of a plugin like this maybe?

plugins:
  - type: mapping_transform
     config:
        - from: {request.headers['X-Request-ID']}
          to: {upstreamRequest.headers['X-Request-ID']}

[dotansimha]

Maybe we should consider to use VRL? https://vector.dev/docs/reference/vrl/