@garethgeorge I was able to add dynamic matrix capability. Unfortunately, I was not able to find GitHub Action support for plain string array on inputs. Had to resort on using a json string array .

Sorry for the confusion @kenneth-rosario, hope I'm not making you go back and forth. Will the value need to be overridden? If it does, I think I prefer your original solution (I think the operation can be run in a matrix in whatever workflow invokes it?). Otherwise, I'm wondering if we can just hard code it in a central place (i.e. here in the conformance test repo) and do away with the input all together.

Ah I see, apologies for misunderstanding will go back to last implementation. I am not sure if its possible to have them all centralized since some of the builders are runtime specific. (e.g. "gcr.io/gae-runtimes/buildpacks/go/builder:latest", "gcr.io/gae-runtimes/buildpacks/google-gae-22/go/builder:latest") We might end up spawning too many runners that do not run (Or might fail).

Nice, thanks Kenneth!