I finally extracted https://github.com/mfojtik/controller-framework from OpenShift library-go for people who want to build Kubernetes controllers the hard way, without operator-sdk or controller-runtime ballast. Enjoy!
https://fly.io is probably the best SaaS hosting I used so far. Super intuitive, transparent billing, nifty UI/CLI, in fact, social.mfojtik.io run there smoothly for last year.
Kubernetes hacker, Gopher, Hiker, Dog Trainer