serverless-plugin-monorepo

A Serverless plugin design to make it possible to use Serverless in a Javascript mono repo with hoisted dependencies, e.g. when using Yarn Workspaces.

This plugin alleviates the need to use nohoist functionality by creating symlinks to all declared dependencies. Development dependencies are deliberately NOT linked so these will not be packaged into the resulting archive.

Butterwire uses Yarn workspaces and we created this plugin to improve our development experience. Not using nohoist saves wasting disk space and also accidentally including development dependencies in our packaged functions.

Note, this package will only work on operating systems that support symbolic links!

Installation

yarn add --dev serverless-plugin-monorepo
# or using NPM
npm install --dev serverless-plugin-monorepo

Currently this plugin requires Node V10+. If there is interest in support older versions then trans-compilation with Babel could be added.

Usage

Add the plugin to your serverless.yml file:

plugins:
  - serverless-plugin-monorepo

The plugin listens for package lifecycle events. Prior to Serverless packaging up the service, it will scan the package.json file for dependencies and ensure that all dependencies (including transitive dependencies) are symlinked in node_modules.

Hence when Serverless creates the archive, it will follow the symlinks and all dependencies will be added as expected. Development/peer dependencies are ignored.

The plugin will run when you do:

• A full deployment (sls deploy)
• Deployment of individual functions (sls deploy -f)
• Spinning up a local sandbox with serverless-offline (sls offline [start])

Settings

On Windows platforms only, the package will create junction links by default as these do not require administrative privileges on older versions of Windows. You can set the linkType setting to dir to create symbolic links instead. This setting is directly passed to the fs.symlink function. It is ignored on non Windows platforms.

Contributing

We welcome issue reports and pull requests!

There is a small run script which will launch Node V14 in a Docker container which you may find useful for development purposes.

Note we are using Prettier with Typescript ESLint and you can run the lint tool via yarn lint which will attempt to automatically issues like spacing etc.

Copyright

Copyright Butterwire Limited 2018 - 2020