Use Redis in Cloudflare Workers

This tutorial showcases using Redis with REST API in Cloudflare Workers. We will write a sample edge function (Cloudflare Workers) which will show a custom greeting depending on the location of the client. We will load the greeting message from Redis so you can update it without touching the code.

Why Upstash?

• Cloudflare Workers does not allow TCP connections. Upstash provides REST API on top of the Redis database.
• Upstash is a serverless offering with per-request pricing which fits for edge and serverless functions.
• Upstash Global database provides low latency all over the world.

Prerequisites

1. Install the Cloudflare Wrangler CLI with npm install wrangler --save-dev

Project Setup

Create a Cloudflare Worker with the following options:

➜  tutorials > ✗ npx wrangler init╭ Create an application with Cloudflare Step 1 of 3│├ In which directory do you want to create your application?│ dir ./greetings-cloudflare│├ What would you like to start with?│ category Hello World example│├ Which template would you like to use?│ type Hello World Worker│├ Which language do you want to use?│ lang TypeScript│├ Copying template files│ files copied to project directory│├ Updating name in `package.json`│ updated `package.json`│├ Installing dependencies│ installed via `npm install`│╰ Application created╭ Configuring your application for Cloudflare Step 2 of 3│├ Installing @cloudflare/workers-types│ installed via npm│├ Adding latest types to `tsconfig.json`│ added @cloudflare/workers-types/2023-07-01│├ Retrieving current workerd compatibility date│ compatibility date 2024-10-22│├ Do you want to use git for version control?│ no git│╰ Application configured

Install Upstash Redis:

cd greetings-cloudflarenpm install @upstash/redis

Database Setup

Create a Redis database using Upstash Console or Upstash CLI and copy the UPSTASH_REDIS_REST_URL and UPSTASH_REDIS_REST_TOKEN into your wrangler.toml file.

# existing config[vars]UPSTASH_REDIS_REST_URL = <YOUR_URL>UPSTASH_REDIS_REST_TOKEN = <YOUR_TOKEN>

Using CLI Tab in the Upstash Console, add some greetings to your database:

Greetings Function Setup

Update src/index.ts:

import { Redis } from '@upstash/redis/cloudflare';type RedisEnv = {	UPSTASH_REDIS_REST_URL: string;	UPSTASH_REDIS_REST_TOKEN: string;};export default {	async fetch(request: Request, env: RedisEnv) {		const redis = Redis.fromEnv(env);		const country = request.headers.get('cf-ipcountry');		if (country) {			const greeting = await redis.get<string>(country);			if (greeting) {				return new Response(greeting);			}		}		return new Response('Hello!');	},};

The code tries to find out the user's location checking the "cf-ipcountry" header. Then it loads the corresponding greeting for that location using the Redis REST API.

Run Locally

Run the following command to start your dev session:

npx wrangler dev

Visit localhost:8787

Build and Deploy

Build and deploy your app to Cloudflare:

npx wrangler deploy

Visit the output url.