Cron Container

To launch a container on a schedule, you can use a Workers Cron Trigger.

For a full example, see the Cron Container Template ↗.

Use a cron expression in your Wrangler config to specify the schedule:

{
	"name": "cron-container",
	"main": "src/index.ts",
	"triggers": {
		"crons": [
			"*/2 * * * *" // Run every 2 minutes
		]
	},
	"containers": [
		{
			"class_name": "CronContainer",
			"image": "./Dockerfile"
		}
	],
	"durable_objects": {
		"bindings": [
			{
				"class_name": "CronContainer",
				"name": "CRON_CONTAINER"
			}
		]
	},
	"migrations": [
		{
			"new_sqlite_classes": ["CronContainer"],
			"tag": "v1"
		}
	]
}

name = "cron-container"
main = "src/index.ts"

[triggers]
crons = [ "*/2 * * * *" ]

[[containers]]
class_name = "CronContainer"
image = "./Dockerfile"

[[durable_objects.bindings]]
class_name = "CronContainer"
name = "CRON_CONTAINER"

[[migrations]]
new_sqlite_classes = [ "CronContainer" ]
tag = "v1"

Then in your Worker, call your Container from the "scheduled" handler:

import { Container, getContainer } from '@cloudflare/containers';

export class CronContainer extends Container {
  sleepAfter = '10s';

  override onStart() {
    console.log('Starting container');
  }

  override onStop() {
    console.log('Container stopped');
  }
}

export default {
  async fetch(): Promise<Response> {
    return new Response("This Worker runs a cron job to execute a container on a schedule.");
  },

  async scheduled(_controller: any, env: { CRON_CONTAINER: DurableObjectNamespace<CronContainer> }) {
    let container = getContainer(env.CRON_CONTAINER);
    await container.start({
      envVars: {
				MESSAGE: "Start Time: " + new Date().toISOString(),
      }
    })
  },
};