One post tagged with "state-machine"

A Player buys a tutorial plan. Somewhere out in GitHub Actions, a Terraform workflow spins up a Scaleway VM, wires up Cloudflare DNS, registers an acme-dns account, and reports back over HTTP. We don't poll it, and we don't hold a connection open for the eight minutes it takes — we wait for it to call us, and when it does, we have to decide in a few milliseconds whether to believe it.

That last part is the whole problem. The workflow is out of band, eventually consistent, and occasionally late. A deploy you kicked off ten minutes ago might still be running when you've given up and started a fresh one — and when that slow old workflow finally phones home, trusting it clobbers the newer environment with its stale view of the world. This post is about the machinery — generations, a drift guard, a two-confirmation null — that lets us listen to an untrusted, asynchronous system without getting burned.