Part of the 3scale documentation:
https://access.redhat.com/documentation/en-us/red_hat_3scale_api_management/2.13/html/administering_the_api_gateway/transform-with-policy-extension_3scale
explains how to call Camel from 3scale. And according to the 3scale docs such integration was tested using Fuse 7.10 on OpenShift. 

Fuse 7.10 is an old version, in addition the code samples may not be current.

This should be updated and tested with with Camel 4.