create-cloudflare/templates/hello-world-workflows/js/src/index.js

A CLI for creating and deploying new applications to Cloudflare.

import { WorkflowEntrypoint } from "cloudflare:workers";

/**
 * Welcome to Cloudflare Workers! This is your first Workflows application.
 *
 * - Run `npm run dev` in your terminal to start a development server
 * - Open a browser tab at http://localhost:8787/ to see your Workflow in action
 * - Run `npm run deploy` to publish your application
 *
 * Learn more at https://developers.cloudflare.com/workflows
 */
 
/**
 * @typedef {Object} Env
 * @property {Workflow} MY_WORKFLOW
 */

/**
 * @typedef {Object} Params
 * @property {string} email
 * @property {Record<string, string>} metadata
 */

export class MyWorkflow extends WorkflowEntrypoint {
	/**
	 * @param {Env} env
	 */
	constructor(env) {
		this.env = env;
	}

	/**
	 * @param {WorkflowEvent<Params>} event
	 * @param {WorkflowStep} step
	 */
	async run(event, step) {
		// Can access bindings on `this.env`
		// Can access params on `event.payload`
		
		const files = await step.do("my first step", async () => {
			// Fetch a list of files from $SOME_SERVICE
			return {
				inputParams: event,
				files: [
					"doc_7392_rev3.pdf",
					"report_x29_final.pdf",
					"memo_2024_05_12.pdf",
					"file_089_update.pdf",
					"proj_alpha_v2.pdf",
					"data_analysis_q2.pdf",
					"notes_meeting_52.pdf",
					"summary_fy24_draft.pdf",
				],
			};
		});

		// You can optionally have a Workflow wait for additional data,
		// human approval or an external webhook or HTTP request before progressing.
		// You can submit data via HTTP POST to /accounts/{account_id}/workflows/{workflow_name}/instances/{instance_id}/events/{eventName}
		const waitForApproval = await step.waitForEvent("request-approval", {
			type: "approval", // define an optional key to switch on
			timeout: "1 minute", // keep it short for the example!
		});

		const apiResponse = await step.do("some other step", async () => {
			let resp = await fetch("https://api.cloudflare.com/client/v4/ips");
			return await resp.json();
		});

		await step.sleep("wait on something", "1 minute");

		await step.do(
			"make a call to write that could maybe, just might, fail",
      // Define a retry strategy
			/** @type {Object} */ ({
				retries: {
					limit: 5,
					delay: "5 second",
					backoff: "exponential",
				},
				timeout: "15 minutes",
			}),
			async () => {
				// Do stuff here, with access to the state from our previous steps
				if (Math.random() > 0.5) {
					throw new Error("API call to $STORAGE_SYSTEM failed");
				}
			},
		);
	}
}

export default {
	/**
	 * @param {Request} req
	 * @param {Env} env
	 * @returns {Promise<Response>}
	 */
	async fetch(req, env) {
		let url = new URL(req.url);

		if (url.pathname.startsWith("/favicon")) {
			return Response.json({}, { status: 404 });
		}

		// Get the status of an existing instance, if provided
		// GET /?instanceId=<id here>
		let id = url.searchParams.get("instanceId");
		if (id) {
			let instance = await env.MY_WORKFLOW.get(id);
			return Response.json({
				status: await instance.status(),
			});
		}

		// Spawn a new instance and return the ID and status
		let instance = await env.MY_WORKFLOW.create();
		// You can also set the ID to match an ID in your own system
		// and pass an optional payload to the Workflow
		// let instance = await env.MY_WORKFLOW.create({
		// 	id: 'id-from-your-system',
		// 	params: { payload: 'to send' },
		// });
		return Response.json({
			id: instance.id,
			details: await instance.status(),
		});
	},
};