Correctly handle exceptions in Akka async continuations - akka.net

Question

To integrate async / task methods with akkling actor system I've written following method
let actorOfTask (t: 'a -> Task<'b>) =
(fun (ctx: Actor<_>) ->
let rec loop() =
actor {
let! data = ctx.Receive()
task {
try
let! t' = data |> t
return t'
with e ->
// TODO : Raise exception in order to supervisor can catch it
printf "Exception %O" e
return raise e
}
|> Async.AwaitTask
|!> ctx.Sender()
}
loop())
It is based on suggestion how to integrate actors with async workflows (example here https://github.com/Horusiath/Akkling/blob/0b5b0ffa4cd516407706ed230f81915452cdb183/tests/Akkling.Tests/Actors.fs#L124)
But issue here if async method throw exception it is not handled by parent supervisor
I'm expecting this code should work but it is not
let ss =
Strategy.OneForOne(fun error ->
printf "Error %O" error
Directive.Escalate)
let system = System.create "sys" <| Configuration.defaultConfig()
spawnAnonymous system { props (eventsHandler env) with SupervisionStrategy = Some ss }
Though if exception happens in regular actor flow (not integrated with async) this supervisor handle it.
Any suggestions how to fix it ?
Thanks

Answer 1

From Akka.Net documentation
https://getakka.net/articles/actors/receive-actor-api.html
WARNING
To complete the Task with an exception you need send a Failure message to the sender. This is not done automatically when an actor throws an exception while processing a message.
try
{
var result = operation();
Sender.Tell(result, Self);
}
catch (Exception e)
{
Sender.Tell(new Failure { Exception = e }, Self);
}
So actor should be implemented like this
let actorOfTask (sendTo: IActorRef<_>) (t: 'a -> Task<_>) =
(fun (ctx: Actor<_>) ->
let rec loop() =
actor {
let! data = ctx.Receive()
task {
try
let! t' = data |> t
return t' :> obj
with e ->
return Akka.Actor.Failure(Exception = e) :> obj
}
|> Async.AwaitTask
|!> (retype sendTo)
}
loop())