Run on Event

This example assumes we have a workflow registered on a running worker.

Run-on-event allows you to trigger one or more workflows when a specific event occurs. This is useful when you need to execute a workflow in response to an ephemeral event where the result is not important. A few common use cases for event-triggered workflow runs are:

1. Running a workflow when an ephemeral event is received, such as a webhook or a message from a queue.
2. When you want to run multiple independent workflows in response to a single event. For instance, if you wanted to run a send_welcome_email workflow, and you also wanted to run a grant_new_user_credits workflow, and a reward_referral workflow, all triggered by the signup. In this case, you might declare all three of those workflows with an event trigger for user:signup, and then have them all kick off when that event happens.

Declaring Event Triggers

To run a workflow on an event, you need to declare the event that will trigger the workflow. This is done by declaring the on_events property in the workflow declaration.

event_workflow = hatchet.workflow(name="EventWorkflow", on_events=["user:create"])

export const lower = hatchet.workflow<Input, LowerOutput>({
  name: 'lower',
  on: {
    event: SIMPLE_EVENT,
  },
});

w.RegisterWorkflow(
    &worker.WorkflowJob{
        Name: "post-user-create",
        On: worker.Event("user:created"),
        Description: "Cron workflow example.",
        Steps: []*worker.WorkflowStep{
            {
                Function: func(ctx context.Context) error {
                    fmt.Println("triggered at:", time.Now())
                    return nil
                },
            },
        },
    },
)

Pushing an Event

You can push an event to the event queue by calling the push method on the Hatchet event client and providing the event name and payload.

hatchet.event.push("user:create", {})

🚨 No snippet found for Pushing an Event 

import { hatchet } from '../hatchet-client';
import { Input, SIMPLE_EVENT } from './workflow';

async function main() {
  const res = await hatchet.events.push<Input>(SIMPLE_EVENT, {
    Message: 'hello',
  });
  // !!

  // eslint-disable-next-line no-console
  console.log(res.eventId);
}

if (require.main === module) {
  main();
}

c.Event().Push(
  context.Background(),
  "test-called",
  &events.TestEvent{
    Name: "testing",
  },
)