iii-cron-scheduling

Original：🇺🇸 English

Translated

Registers cron triggers with 7-field expressions to run functions on recurring schedules. Use when scheduling periodic jobs, timed automation, crontab replacements, cleanup routines, report generation, health checks, batch processing, or any task that should run every N seconds, minutes, hours, or on a weekly/monthly calendar.

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Sourceiii-hq/skills

Added on2026-04-21

NPX Install

npx skill4agent add iii-hq/skills iii-cron-scheduling

SKILL.md Content

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Cron Scheduling

Comparable to: node-cron, APScheduler, crontab

Key Concepts

Use the concepts below when they fit the task. Not every scheduled job needs all of them.

Cron expressions use a 7-field format:

second minute hour day month weekday year

CronModule evaluates expressions and fires triggers on schedule
Handlers should be fast — enqueue heavy work to a queue instead of blocking the cron handler
Each cron trigger binds one expression to one function
Overlapping schedules are fine; each trigger fires independently

Architecture

CronModule timer tick
  → registerTrigger type:'cron' expression match
    → registerFunction handler
      → (optional) TriggerAction.Enqueue for heavy work

iii Primitives Used

Primitive	Purpose
`registerFunction`	Define the handler for the scheduled job
`registerTrigger({ type: 'cron' })`	Bind a cron expression to a function
`config: { expression: '0 0 9 * * * *' }`	Cron schedule in 7-field format

Reference Implementation

See ../references/cron-scheduling.js for the full working example — a recurring scheduled task that fires on a cron expression and optionally enqueues heavy work.

Also available in Python: ../references/cron-scheduling.py

Also available in Rust: ../references/cron-scheduling.rs

Common Patterns

Code using this pattern commonly includes, when relevant:

```
registerWorker(url, { workerName })
```
— worker initialization
```
registerFunction(id, handler)
```
— define the scheduled handler

registerTrigger({ type: 'cron', config: { expression } })

— bind the schedule

trigger({ function_id, payload, action: TriggerAction.Enqueue({ queue }) })

— offload heavy work

```
const logger = new Logger()
```
— structured logging per job

Adapting This Pattern

Use the adaptations below when they apply to the task.

Adjust the 7-field expression to match your schedule (e.g.
```
0 0 */6 * * * *
```
for every 6 hours)
Keep the cron handler lightweight — use it to validate and enqueue, not to do the heavy lifting
For jobs that need state (e.g. last-run timestamp), combine with
```
iii-state-management
```
Multiple cron triggers can feed the same queue for fan-in processing

Engine Configuration

CronModule must be enabled in iii-config.yaml. See ../references/iii-config.yaml for the full annotated config reference.

Pattern Boundaries

If the task is about one-off async work rather than recurring schedules, prefer
```
iii-queue-processing
```
.
If the trigger should fire on state changes rather than time, prefer
```
iii-state-reactions
```
.
Stay with
```
iii-cron-scheduling
```
when the primary need is time-based periodic execution.

When to Use

Use this skill when the task is primarily about
```
iii-cron-scheduling
```
in the iii engine.
Triggers when the request directly asks for this pattern or an equivalent implementation.

Boundaries

Never use this skill as a generic fallback for unrelated tasks.
You must not apply this skill when a more specific iii skill is a better fit.
Always verify environment and safety constraints before applying examples from this skill.