The serverless computing paradigm introduced a lot of opportunities to create more scalable and cost-efficient software, but it also came with its own challenges, some of which we harshly experienced.

After more than two years spent building multiple real-world applications, ranging from small startups to large groups, we decided to share our learnings and help other teams build awesome products.

This is why we would like to introduce Swarmion, an open-source framework, dedicated to Serverless microservices. A great emphasis has been done on developer experience, since working with a Typescript monorepo is a challenge.

What is Swarmion?

Swarmion is an open-source framework for building type-safe Serverless microservices at scale. It takes full advantage of theServerless Frameworkto handle provisioning and deployment of resources, while adding support for microservices and end-to-end type-safety.

It is composed of two parts:

• a template for starting state-of-the-art projects
• a set of tools and plugins, to ease the communication between microservices and secure their deployment

Today, we are going to focus on the first part, stay tuned for more articles...

TL:DR: try it out! Head to the end of this article for a quick tutorial!

Our core beliefs

Your codebase should adapt to your team organization

Changes in the way you organize your teams should not have an impact on the speed at which you can develop and deploy new features. Therefore, Swarmion uses a flexible microservices approach in a monorepo.

DRY (Don't Repeat Yourself)

Having several teams working in the same environment requires efficient collaboration. Swarmion allows to clearly separate the shared logic and interfaces from the service-specific logic for better decoupling.

Developer experience is key for code quality

As your codebase grows, testing and deployment times are likely to skyrocket. Swarmion uses optimized low-level software (esbuild, vitejs) to reduce testing and building times and a smart monorepo management tool (Nx) to provide a top-level developer experience and reduce CI/CD delays.

Template features

The template comes with state of the art tooling for a Typescript monorepo. The main philosophy is to allow easy customization of the different tools used in the packages, without having to write too many code; every tool can be configured at the root level and extended through composition at the package level.

Yarn 3 with workspaces

Yarn 3 and workspaces allows to create a monorepo with multiple packages, each with their own dependencies. Every package in the monorepo is considered as an npm package inside the monorepo. Every modification to its source code is instantly available to the other packages.

Nx

A powerful and extensible build system, Nx, is used to manage dependencies between packages, provide visualization of the monorepo dependencies through the yarn nx graph command and gain access to powerful custom generators. Our nx plugin already has two generators, for libraries and serverless services (more are coming).

Nx also avoids unnecessary computation when running commands inside the monorepo, using local caching and changes detection for an smooth developer experience and an optimized CI/CD.

Typescript

Since every package inside the monorepo is using Typescript, every line of code can be statically checked. A strict and strong Typescript configuration is located at the root level, extended throughout the packages using composition.

ESLint

A comprehensive set of formatting (through eslint-plugin-prettier) and linting rules, generated with Clinter. Once again, each package can easily extend the root configuration.

Shared Typescript libraries

One of the main challenges of a Typescript monorepo is to build shared Typescript libraries. Packages are transpiled in cjs, esm (thanks to Babel) and .d.ts Typescript declaration file, to enable any usage across the monorepo.

Jest

Every package has testing configured through jest, with a default configuration that can easily be extended, thanks to the jest.config.ts file at the package level.

VS Code support

Each package in the monorepo is defined as a workspace in the multi-root workspaces. It enables easier browsing and searching features, bringing the same navigation than in a standard codebase.

Using multi-root workspaces makes it possible to use the great vs-code extension, which makes it possible to run and debug tests directly inside VS Code.

Generate a project with Swarmion

To create a Swarmion project, head to https://github.com/swarmion/template.

Click the "use this template" button

And you're all set! Follow the install docs.

Quick overview

The generated repo will have the following structure.

 backend/|    core/                       # core service|    users/                      # users service|    ...                         # other deployed services| frontend/|    app/|    cloudfront/|    ...                         # other deployed services| commonConfiguration/            # configuration files such as jest, babel...|    babel.config.js|    lintstaged-base-config.js| contracts/                      # JSONSchema-based binding contracts|    core-contracts/|    users-contracts/|    ...                         # other contracts, used between deployed services| packages/|    configuration/              # common constants used in all services|    serverless-configuration/   # common constants used in all serverless deployed services|    serverless-helpers/         # a set of shared helpers|    ...                         # other internal shared packages| package.json                   # shared dependencies and global scripts yarn.lock                      # unique lock file, using yarn workspaces

To learn more about this structure, head to the documentation!

Wrapping up

Be sure to check out https://www.swarmion.dev/ for docs about Swarmion, the template repo and the tools repo. Any feedback is welcome!

Upcoming features

Swarmion is being maintained by a core team of several people, we are striving to deliver more and more features:

• a create-swarmion-app script to create an app even more easily
• more contracts in our library to define type-safe and runtime interactions between services
• frontend generators for apps and libraries

Acknowledgments

Swarmion was created by Adrien Cacciaguerra and Franois Farge.

• @adriencaccia - adriencaccia

• @farge_francois - fargito

Thanks to the swarmion team: Guillaume Duboc, Maxime Vivier, Axel Fournier and Stanislas Hannebelle.

Thanks to all the contributors!

Thanks to Theodo for sponsoring this project!