Managing multiple Workers projects with Lerna
Before you start
All of the tutorials assume you have already completed the Get started guide, which gets you set up with a Cloudflare Workers account, and the Workers CLI tool, Wrangler.
Overview
Using lerna
, a tool for managing multiple JavaScript codebases inside a single monorepo, developers can work with multiple Wrangler projects and share dependencies between them. If your codebase is already managed with lerna
, you can also add a new Wrangler project into your existing monorepo without disrupting your workflow.
Begin by installing lerna
, and creating a new project in the folder workers-monorepo
:
Install lerna and init a new project$ npm install -g lerna
$ mkdir workers-monorepo && cd workers-monorepo
$ lerna init
Inside of packages
, where lerna
will look for your projects, you can create multiple new Wrangler codebases, or even git clone
your existing Workers codebase to migrate it into a lerna
monorepo:
Create projects using Wrangler$ cd packages
$ wrangler init my-api
# If you have existing projects, you can clone them into the directory:
$ git clone https://github.com/cloudflare/worker-template.git
This approach to managing your Workers projects can become incredibly powerful when you begin to share dependencies between projects. Imagine that your codebase has a pre-defined set of API handlers that you want to reuse between your public and private APIs, in the packages public-api
and private-api
:
Create projects using Wrangler$ cd packages
$ wrangler init public-api
$ wrangler init private-api
Next to your API projects, create a new package handlers
, which can be imported into each project:
Create a new lerna package$ lerna create handlers
packages/public-api/package.json{ "dependencies": { "handlers": "1.0.0" }
}
Link the packages together using the bootstrap
command and use them inside of your code:
Link packages using lerna bootstrap$ lerna bootstrap
packages/public-api/index.js// Omitting addEventListener and boilerplate code
import { json } from 'handlers';
const handler = request => { return json({ status: 200 });
};
After adding an identical dependency
to private-api/package.json
, run lerna bootstrap
again, and begin sharing code between your projects.
When you are ready to deploy your codebases, define a script in each package’s package.json
file (for example, publish
), so that you can later deploy both codebases in a coordinated manner using the command lerna run <SCRIPT_NAME>
:
packages/public-api/package.json{ "name": "public-api", "scripts": { "publish": "wrangler publish" }
}
packages/private-api/package.json{ "name": "private-api", "scripts": { "publish": "wrangler publish" }
}
lerna run publish
will look for the publish
script defined in each package’s project.json
, and if the project defines it, it will run the script inside of that project’s directory:
Publish packages using lerna run~/workers-monorepo $ lerna run publish
lerna info Executing command in 2 packages: "npm run publish"lerna info run Ran npm script "publish" in "public-api" in 4.8s:
> public-api@1.0.0 publish /workers-monorepo/packages/public-api> wrangler publish
lerna info run Ran npm script "publish" in "private-api" in 6.5s:
> private-api@1.0.0 publish /workers-monorepo/packages/private-api> wrangler publish
lerna success run Ran npm script "publish" in 2 packages in 6.5s:lerna success - public-apilerna success - private-api
Related resources
If you would like to review an example repository, refer to the accompanying open-source codebase on GitHub for this tutorial.