@petriflow/engine

Petri net workflow engine with guards, executors, timeouts, persistence, and scheduling. Extends petri-ts with runtime capabilities for building stateful workflows.

Used by @petriflow/gate (tool access control) and @petriflow/rules (declarative DSL).

Install

npm install @petriflow/engine

Usage

import { defineWorkflow, toNet, analyse } from "@petriflow/engine";

const workflow = defineWorkflow({
  name: "order",
  places: ["pending", "approved", "shipped"] as const,
  initialMarking: { pending: 1, approved: 0, shipped: 0 },
  transitions: [
    {
      name: "approve",
      inputs: ["pending"],
      outputs: ["approved"],
      guard: (marking) => marking.pending > 0,
    },
    {
      name: "ship",
      inputs: ["approved"],
      outputs: ["shipped"],
    },
  ],
});

// Analyse reachable states, deadlocks, invariants
const result = analyse(workflow);
console.log(result.reachableStates); // 3
console.log(result.deadlockFree);   // false (shipped is terminal)

// Strip extensions for pure petri-ts analysis
const net = toNet(workflow);

Exports

| Export path | Description | |---|---| | @petriflow/engine | Core engine: workflow definition, guards, executors, scheduling, persistence | | @petriflow/engine/analyse | analyse() — reachable states, deadlock detection, invariant checking | | @petriflow/engine/workflow | defineWorkflow(), toNet() | | @petriflow/engine/types | TypeScript types only | | @petriflow/engine/decision | Decision provider types for human-in-the-loop |

All petri-ts functions and types are re-exported from the main entry point (canFire, fire, reachableStates, Marking, Transition, etc.).

Key concepts

WorkflowTransition — extends petri-ts Transition with optional guard, execute, timeout, and config fields. The intersection type (Transition & { ... }) ensures structural compatibility with all petri-ts functions — no adapters needed.

toNet() — strips guard/execute/timeout extensions, returning a plain PetriNet for pure analysis with petri-ts functions like reachableStates() and isDeadlockFree().

Persistence — SQLite adapter via bun:sqlite for saving/loading workflow instances, transition history, and timeout entries.

Scheduler — tick-based execution loop with re-entrancy protection, timeout handling, and event hooks.

Tests

bun test packages/engine