PuduLangResilience.Domain.Algorithms

type: module path: "@root/src/PuduLangResilience/Domain/Algorithms.pudu" fidelity: Active grammar: "[[grammar/pudu]]" depth_score: 0.75 depth_status: DEEP tags: [module, deep] aliases: [PuduLangResilience.Domain.Algorithms]

Purpose

How each limiter kind counts: concurrency, token bucket, fixed window, and sliding window.

Interface

Signatures

export type Bucket = { tokens: Int, stamp: Int }

export type Window = { used: Int, start: Int }

export type Segments = { counts: Array[Int], start: Int }

export fn concurrency(limit: Int) -> Permits.Algorithm[Int]

export fn tokenBucket(limit: Int, perPeriod: Int, period: Int, automatic: Bool) -> Permits.Algorithm[Bucket]

export fn fixedWindow(limit: Int, window: Int, automatic: Bool) -> Permits.Algorithm[Window]

export fn slidingWindow(limit: Int, window: Int, segments: Int, automatic: Bool) -> Permits.Algorithm[Segments]

export fn shifted(counts: &Array[Int], steps: Int) -> Array[Int]

Linkage

• Requires: [[src/PuduLangResilience/Domain/Permits]], [[src/PuduLangResilience/Utils/Numeric]], Std.Math.
• Consumed by: [[src/PuduLangResilience/Limiter/Concurrency]], [[src/PuduLangResilience/Limiter/FixedWindow]], [[src/PuduLangResilience/Limiter/SlidingWindow]], [[src/PuduLangResilience/Limiter/TokenBucket]].

Algorithm

1. Concurrency: permits leave on grant and return on release.
2. Token bucket: whole periods since the last refill add tokens up to the limit; the retry time is the periods needed less the time already passed.
3. Fixed window: whole windows since the start reset the count; the retry time is the rest of the window.
4. Sliding window: whole segments since the start shift out the oldest counts; the retry time is when enough old segments leave.

Negative Logic (Prohibited Paths)

• Manual replenishment kinds never refill with time and give no retry time.

Edge Cases

• Shifting past every segment empties them.

Depth

DEPTH 0.75 (DEEP). Tested by the suite mirroring this module under test/.

Grill Log

• Q: Why one module for four algorithms? A: Each is a handful of pure functions sharing the same record shape. _Rejected:_ four shallow modules.

Referenced by

[[src/PuduLangResilience/Domain/Permits]] · [[src/PuduLangResilience/Domain/_MOC]] · [[src/PuduLangResilience/Limiter/Concurrency]] · [[src/PuduLangResilience/Limiter/FixedWindow]] · [[src/PuduLangResilience/Limiter/SlidingWindow]] · [[src/PuduLangResilience/Limiter/TokenBucket]] · [[src/PuduLangResilience/Utils/Numeric]] · [[subsystems/Limiting]]