Schedules and Intervals

Use a schedule for calendar time and an interval for a fixed-rate elapsed grid.

Calendar schedules

<schedule id="dailyReport" cron="0 8 * * *" timezone="Europe/Berlin" on-missed="run-once" />

Cron uses five fields: minute, hour, day of month, month, and day of week. WOML supports wildcards, lists, ranges, and steps. Timezone defaults to UTC and otherwise uses a canonical IANA name.

Fixed intervals

<interval id="refreshCache" every="5m" on-missed="skip" />

every accepts a duration from 1 second through 30 days. The schedule remains anchored, so a slow run does not shift future planned instants.

Missed occurrences

on-missed="skip" ignores missed instants. run-once admits one catch-up occurrence. Both trigger types provide { scheduledAt, triggeredAt } timestamps in context.payload.

Choose calendar time or elapsed time

Use a schedule when humans describe the requirement with a calendar: “every weekday at 08:00 in Berlin.” Use an interval when the requirement is elapsed repetition: “every five minutes from the runtime's anchored grid.”

A schedule is timezone-aware. An interval is not a replacement for a calendar promise because daylight-saving changes and wall-clock meaning are not part of its contract.

Build a scheduled report

<woml>
  <workflow id="daily-report" name="Daily report" version="1.0.0">
    <triggers>
      <schedule
        id="morningReport"
        cron="0 8 * * 1-5"
        timezone="Europe/Berlin"
        on-missed="run-once"
      />
    </triggers>
    <steps>
      <step id="report" name="Build report">
        <script>
          return {
            scheduledAt: context.payload.scheduledAt,
            startedAt: context.payload.triggeredAt
          };
        </script>
      </step>
    </steps>
  </workflow>
</woml>

WOML cron uses five numeric fields: minute, hour, day of month, month, and day of week. It supports wildcards, lists, inclusive ranges, and steps. It does not support seconds, names, macros, wrapping ranges, or Quartz-only tokens.

Build a fixed interval

<interval id="refreshCache" every="5m" on-missed="skip" />

Intervals accept durations from 1s through 30d. The planned schedule remains anchored, so a slow run does not permanently move every future occurrence later.

Understand missed runs

If the runtime is stopped during planned occurrences, skip ignores those missed instants. run-once admits one catch-up run after recovery rather than replaying every missed occurrence.

Choose deliberately. A monitoring refresh often uses skip; a once-daily business report may need run-once. Neither policy guarantees the external effects inside the workflow are safe to repeat.

Test time-based workflows

During development, temporarily add a manual trigger or use a short interval in a non-production copy. Do not change a production cron merely to test business logic. Keep the workflow steps trigger-independent by reading normalized payload fields only when they are relevant.