PuduLangResilience.Hedging.Attempts

type: module path: "@root/src/PuduLangResilience/Hedging/Attempts.pudu" fidelity: Active grammar: "[[grammar/pudu]]" depth_score: 0.7 depth_status: DEEP tags: [module] aliases: [PuduLangResilience.Hedging.Attempts]

Purpose

Runs one hedged attempt on its own thread, stores its outcome, and signals completion; waits for the next finished attempt; ends all attempts.

Interface

Signatures

export type Attempt[T, E] = {
  index: Int,
  context: Context.Context,
  started: Int,
  outcome: Shared.Shared[Option[Resilience.Outcome[T, E]]],
  worker: Option[Concurrent.Task]
}

export const FOREVER: Int = -1

export fn launch[T, E](index: Int, context: Context.Context, callback: fn(Context.Context) -> Resilience.Outcome[T, E], finished: &Channel.Channel[Int], started: Int) -> Attempt[T, E]

export fn next(finished: &Channel.Channel[Int], clock: &Clock.Clock, wait: Int) -> Option[Int]

export fn outcomeOf[T, E](attempt: &Attempt[T, E]) -> Resilience.Outcome[T, E]

export fn settle[T, E](attempts: &Array[Attempt[T, E]], why: Str) -> ()

Linkage

• Requires: [[src/PuduLangResilience/Clock]], [[src/PuduLangResilience/Context]], [[src/PuduLangResilience]], [[src/PuduLangResilience/Utils/Shared]], Std.Channel, Std.Concurrent, Std.Concurrent.Cancel.
• Consumed by: [[src/PuduLangResilience/Hedging]].

Algorithm

1. An attempt runs inside Concurrent.contain on a thread; its outcome, or Crashed, is stored before its index is sent to the completion channel.
2. next waits for the channel with a bound, polling on the pipeline clock, or without one for FOREVER.
3. settle cancels every attempt's token and joins every thread.

Negative Logic (Prohibited Paths)

• Every attempt signals completion exactly once, even when it cannot start.

Edge Cases

• An attempt whose thread cannot start finishes at once as Crashed.

Depth

DEPTH 0.7 (DEEP). Tested by the suite mirroring this module under test/.

Grill Log

• Q: Why poll the channel for a bounded wait? A: Std.Channel has no timed receive; polling the pending count on the pipeline clock keeps the wait cancellable and testable. _Rejected:_ a timer thread per wait.

Referenced by

[[src/PuduLangResilience]] · [[src/PuduLangResilience/Clock]] · [[src/PuduLangResilience/Context]] · [[src/PuduLangResilience/Hedging]] · [[src/PuduLangResilience/Hedging/_MOC]] · [[src/PuduLangResilience/Utils/Shared]]