AWS Lambda: how to share code in a monorepo

A while back, a client asked me “how can I share business logic between services in a Node.js monorepo?”. The TL;DR of it is:

• Encapsulate the shared business logic into modules, and put them in a separate folder.
• In the Lambda handler functions, reference the shared modules using relative paths.

• Use webpack to resolve and bundle them into the deployment package. If you use the Serverless framework, then check out the plugin. For example:

• Deploy every service on every commit. You can do this with a simple script like the following.

To see how everything fits together, check out . It has CI/CD set up already through and you can see a recent deployment of all the services in the monorepo . But wait! How do I choose between having a monorepo vs a repo per service? Don’t worry, I’ve got you covered for that too ;-) You can read about my thoughts on the two approaches .

Hi, my name is Yan Cui. I’m an and the author of . I have run production workload at scale in AWS for nearly 10 years and I have been an architect or principal engineer with a variety of industries ranging from banking, e-commerce, sports streaming to mobile gaming. I currently work as an independent consultant focused on AWS and serverless.

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Originally published at on June 29, 2019.