Setting Cron Triggers

JavaScript

export default {
  async scheduled(controller, env, ctx) {
    console.log("cron processed");
  },
};

TypeScript

interface Env {}
export default {
  async scheduled(
    controller: ScheduledController,
    env: Env,
    ctx: ExecutionContext,
  ) {
    console.log("cron processed");
  },
};

Python

from workers import handler

@handler
async def on_scheduled(controller, env, ctx):
  print("cron processed")

Hono

import { Hono } from 'hono';

interface Env {}

// Create Hono app
const app = new Hono<{ Bindings: Env }>();

// Regular routes for normal HTTP requests
app.get('/', (c) => c.text('Hello World!'));

// Export both the app and a scheduled function
export default {
  // The Hono app handles regular HTTP requests
  fetch: app.fetch,

  // The scheduled function handles Cron triggers
  async scheduled(
    controller: ScheduledController,
    env: Env,
    ctx: ExecutionContext,
  ) {
    console.log("cron processed");

    // You could also perform actions like:
    // - Fetching data from external APIs
    // - Updating KV or Durable Object storage
    // - Running maintenance tasks
    // - Sending notifications
  },
};

Set Cron Triggers in Wrangler

Refer to Cron Triggers for more information on how to add a Cron Trigger.

If you are deploying with Wrangler, set the cron syntax (once per hour as shown below) by adding this to your Wrangler file:

wrangler.jsonc

{
  "name": "worker",
  "triggers": {
    "crons": [
      "0 * * * *"
    ]
  }
}

wrangler.toml

name = "worker"

# ...

[triggers]
crons = ["0 * * * *"]

You also can set a different Cron Trigger for each environment in your Wrangler configuration file. You need to put the [triggers] table under your chosen environment. For example:

wrangler.jsonc

{
  "env": {
    "dev": {
      "triggers": {
        "crons": [
          "0 * * * *"
        ]
      }
    }
  }
}

wrangler.toml

[env.dev.triggers]
crons = ["0 * * * *"]

Test Cron Triggers using Wrangler

The recommended way of testing Cron Triggers is using Wrangler.

Cron Triggers can be tested using Wrangler by passing in the --test-scheduled flag to wrangler dev. This will expose a /__scheduled (or /cdn-cgi/handler/scheduled for Python Workers) route which can be used to test using a HTTP request. To simulate different cron patterns, a cron query parameter can be passed in.

npx wrangler dev --test-scheduled

curl "http://localhost:8787/__scheduled?cron=0+*+*+*+*"

curl "http://localhost:8787/cdn-cgi/handler/scheduled?cron=*+*+*+*+*" # Python Workers