Pairs with https://github.com/clutterstack/where_machines.
The Useless Machine portion of https://where.fly.dev, a toy web application that exercises some standout features of the Fly.io platform: the Machines API for on-demand VMs, private networking, Anycast routing, and quasi-programmable request routing with fly-proxy and the fly-replay header.
A visitor to https://where.fly.dev pushes a button, which spawns a Fly Machine VM running this little Phoenix/LiveView server, which plays a short animation before shutting itself down. The Machine is configured such that the platform destroys it on shutdown.
I wrote about how this app uses fly-replay to enforce the one-to-one mapping between visitors and their very own ephemeral VMs: Machine Affinity with LiveView and fly-replay.
(More in the README for https://github.com/clutterstack/where_machines)
- sticky sessions (distinct from auth, because it's not a matter of providing the info appropriate to a user who has a particular cookie, but of potentially redirecting every connection)
- animation is a bunch of text files that originated as hand-drawn art, just because
- local health check endpoint and API client to tell
where_machinesthat the Machine is ready to serve requests - disconnects WebSocket and heads to a regular Phoenix view before shutting down, so local LiveView JS doesn't keep trying to reconnect