Durable Trigger Cancel

Goal

Define one cooperative durable trigger, enqueue it, request cancellation, and observe the terminal cancellation fact.

What You Build

An app-owned trigger with acquire, commit, and commitCancelled, registered through the Cloudflare DO facade.

Prerequisites

• Durable triggers guide
• Cloudflare DO backend
• Durable truth

Steps

1. Define a cooperative trigger:

   const trigger = {
     kind: "tutorial.cancelable",
     intentEventKind: "tutorial.cancelable.requested",
     cancellation: "cooperative",
     parseIntent,
     acquire: (intent, ctx) => runExternalWork(intent, { signal: ctx.signal }),
     commit: (outcome, tx) => {
       tx.insertEvent({ kind: "tutorial.cancelable.done", payload: outcome });
     },
     commitCancelled: (intent, cancellation, tx) => {
       tx.insertEvent({
         kind: "tutorial.cancelable.cancelled",
         payload: { id: intent.id, reason: cancellation.reason ?? null },
       });
     },
   } satisfies DurableTrigger<TutorialIntent, TutorialOutcome>;

2. Register it:

   export const AgentDO = defineAgentDO<Env>({
     bindings: [],
     triggers: [trigger],
   });

3. Enqueue work and keep the returned intent id:

   const intent = await agent.enqueueTrigger({
     triggerKind: "tutorial.cancelable",
     payload: { id: "job-1" },
     at: Date.now(),
   });

4. Request cancellation:

   const cancel = await agent.cancelTrigger({
     triggerKind: "tutorial.cancelable",
     intentEventId: intent.id,
     reason: "user",
   });

5. Read ledger events or your app projection for tutorial.cancelable.cancelled.

Checkpoint

Interpret cancel.status as the request path:

cancelled          pending row was terminally cancelled now
requested          running row was marked and ctx.signal was aborted
ignored            trigger declared cancellation: "ignored"
not_found          no matching pending work exists
already_completed  terminal success won before cancellation

The terminal user-visible fact still comes from commit or commitCancelled. Cancellation is cooperative; it is not a hidden timeout or forced discard of an already completed provider call.

Next

Add live progress with output-only attached streams.