I really like approach of buildkite CI -- they use yaml, but this yaml can be produced by an executable script. So you write yaml by hand for trivial cases, bu

I really like approach of buildkite CI -- they use yaml, but this yaml can be produced by an executable script. So you write yaml by hand for trivial cases, but once it get complex, you can just drop back to shell/python/ruby/node/whatever, implement any complex logic, and serialize results to plain yaml.