Lesson 1: Bootstrap a Headless App

First, you need a new headless app created with AIO CLI. This app needs only a simple action to test the cron job, so all other components have been deselected. Follow this, from Creating your First App Builder Application

Now edit the action code at actions/generic/index.js to simplify it. We will make it print the current execution time to logs, and return it in the result:

const { Core } = require('@adobe/aio-sdk')

async function main (params) {
  const logger = Core.Logger('main', { level: 'info' })

  try {
    logger.info('Calling the main action')
    const currentTime = new Date()
    logger.info(`Current time is ${currentTime.toLocaleString()}.`)

    return {
      timeInMilliseconds: currentTime.getTime(),
      timeInString: currentTime.toLocaleString()
    }
  } catch (error) {
    logger.error(error)
    return { error }
  }
}

exports.main = main

Because the action is invoked only by internal alarms, it does not need to be exposed as a web action. This prevents the action from being accessed by unprivileged users. Your manifest file should look like this:

application:
  actions: actions
  web: web-src
  runtimeManifest:
    packages:
      my-app:
        license: Apache-2.0
        actions:
          generic:
            function: actions/generic/index.js
            web: 'yes'
            runtime: 'nodejs:14'

To test the action, you could execute aio app deploy in the VSCode terminal. Once the deployment is finished, run aio rt action invoke your-app-name/generic and verify its result and logs using aio rt activation get ID and aio rt activation logs ID (ID is available in the output of the invoke command earlier). This is an extract of the result from the activation information: