StatifierOban

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Durable timers and async invoke execution for Statifier, backed by Oban.

Statifier's session runs delayed sends on Process.send_after/3, so every in-flight timer dies with the node: a deploy silently drops every pending delayed send. Charts with human-timescale delays - follow-ups, escalations, timeouts measured in hours or days - need the timers to outlive the process. This package consumes Statifier's effect vocabulary and schedules that work in Oban instead.

Installation

def deps do
  [
    {:statifier_oban, "~> 0.1"}
  ]
end

Status

Early, under active development. Delayed sends run through Oban end to end - schedule from the SendDelayed effect, cancel from the Cancel effect, deliver behind the run-liveness check - and use StatifierOban.Invoke.Handler is the Oban-backed invoke handler base on statifier's handler registry.

The contract this package implements

The host-facing pattern is already specified upstream, and this package is one implementation of it rather than the definition of it:

  • docs/durable-timers.md in statifier-ex is the recipe: consume the effect, schedule externally, feed the fired event back in.
  • ADR-0054 there records the rules a durable-timer host works to - consume the effect vocabulary rather than the instruction vocabulary, the re-entry door, how stored timers are keyed, and what replaces the SCXML 6.2 discard-on-termination guarantee. ADR-0055 records the routing limit below.

Read both before adding code here. One limit recorded upstream shapes what this package can promise:

  • The contract covers delayed sends that resolve to the session itself. A send routed to #_internal, #_parent, #_invokeid, or an external session is left to the library, because the resolved route does not travel on the effect.

(An earlier limit is gone: ADR-0059 in statifier-ex added a per-execution ordinal to the durable-timer effects, so a hand-written id on a <send delay="..."> inside a <foreach> is fully supported and the old leave-the-id-off guidance is retired.)

Scope

In scope: delayed sends into Oban jobs with cancellation, and an Oban-backed invoke-handler base built on Statifier's per-session handler registry.

Out of scope: storage of chart state, and the handler registry itself. Both belong to other packages.