Heroku hacker here. Buildpacks are definitely designed with composability in mind. Here are a couple already existing higher-order buildpacks: https://github.co

Heroku hacker here. Buildpacks are definitely designed with composability in mind. Here are a couple already existing higher-order buildpacks: https://github.com/ddollar/heroku-buildpack-multi https://github.com/ddollar/heroku-buildpack-multi and https://github.com/kr/heroku-buildpack-inline https://github.com/kr/heroku-buildpack-inline