Defines a behavior for a FLAME backend.

A FLAME backend is responsible for booting remote compute resources, connecting them back to the parent node, and executing functions on them.

The default FLAME.LocalBackend simply runs your code locally, allowing you to develop and test your application using FLAME.call/3 without running an external backend.

Messaging

The FLAME.Terminator process runs on remote nodes automatically and is responsible for connecting back to the parent node, notifying the parent, and handling termination of remote processes started via FLAME.call/3, FLAME.cast/3, and FLAME.place_child/3. When the terminator starts on a newly booted remote node, it sends the following message to the parent runner process:

{ref, {:remote_up, remote_terminator_pid}}

Where ref is the reference generated by the backend and encoded into the FLAME.Parent.encode/1 string.

When the remote terminator is going away gracefully, it sends the following message:

{ref, {:remote_shutdown, :idle}}

Backend implementations can react to these messages to handle the remotely provisioned instance booting up or shutting down.

See FLAME.FlyBackend for an example implementation of this behavior.