Adding mist server under supervisor

[steel karma]

I was trying to buld the scaffold of a web app built with mist and thought adding the resulting mist server as part of the supervision tree would be neat idea.

pub fn main() {
  let assert Ok(_) = supervisor()
  process.sleep_forever()
}

fn supervisor() {
  supervisor.start(fn(children) {
    children |> supervisor.add(server_childspec())
  })
}

fn server_childspec() {
  supervisor.supervisor(fn(_caller) { serve() })
}

fn serve() {
  mist.new(pipeline)
  |> mist.port(8088)
  |> mist.start_http()
}

The above doesn't quite work because the supervision spec is expecting an actor.StartError type but mist does have a glisten.StartError.

error: Type mismatch
   ┌─ /Users/chouzar/Bench/Playground/cochito/src/cochito.gleam:26:25
   │
26 │   supervisor.supervisor(fn(_caller) { serve() })
   │                         ^^^^^^^^^^^^^^^^^^^^^^^

Expected type:

    fn(Nil) -> Result(Subject(Message), StartError)

Found type:

    fn(Nil) -> Result(Subject(Message), glisten.StartError)

Does it make sense to add a mist server as part of the app supervision tree? Is it designed to be standalone?

@eager bronze would appreciate any guide if you're available 🙏

[terse cliff]

Just write the function to erode the info that glisten’s starterror type gives you back into a normal actor start error

Mist is gonna most typically be used outside of supervision so it makes sense for it to have a start error type with more precision so the developer can handle different errors

But if you dont need that then you should write the function to take that info away and get back a regular ol’ start error, nothing wrong with that!

[steel karma]

Ah of course 😅 that train of thought makes a lot of sense, thanks @terse cliff 🙂

[eager bronze]

lol damn, guess i'm not needed again

[terse cliff]

Im sorry 😭😭

[eager bronze]

it's helpful and appreciated ofc 🙂

[steel karma]

Thanks @eager bronze 💜