I recently worked on a small TypeScript project which I wanted to deploy as a Lambda to AWS.
My project had multiple files and some npm dependencies.
I found some resources online, but none of them really hit the spot.
Some didn’t explain how to include the node_modules
, some didn’t explain how to do it with TypeScript and some just handled a single file.
In this post, I’ll describe how to prepare the project for deployment and show a detailed example of doing it using Github Actions.
Project Structure
Let’s assume our project structure looks like this:
├── package.json
├── tsconfig.json
├── node_modules
│ ├── module_1
│ ├── module_2
│ └── etc..
└── src
├── index.ts
└── utils.ts
This is our tsconfig.json
:
{
"compilerOptions": {
"module": "commonjs",
"target": "ES2017",
"lib": ["ES2019"],
"rootDir": "src",
"outDir": "dist",
"declaration": false,
"sourceMap": false,
"inlineSources": false,
"types": ["node"]
}
}
And index.ts
contains as the main handler
, and uses utils.ts
, something like this:
import { APIGatewayEvent, Context } from 'aws-lambda';
import { doSomething } from './utils';
export const handler = async (event: APIGatewayEvent, context: Context) => {
doSomething();
// Do some other stuff…
}
Problem
AWS Lamda can only run js files!
Also, AWS Lambda can’t install node_modules
for us.
With the default settings, AWS Lambda supports either:
- Deploying a single
index.js
file directly. - Upload a zip file containing all the project files, which has the
index.js
in the zip root.
So we need to zip the project correctly, without including the parent directory.
We also need to make sure the node_modules
are part of this zip file.
Prepare for deployment
1. Build the project
We will use TypeScript’s tsc
command to transpile the project into js files.
After building, this will be our project structure:
├── package.json
├── tsconfig.json
├── node_modules
├── dist
│ ├── index.js
│ └── utils.js
└── src
├── index.ts
└── utils.ts
2. Move node_modules to dist folder
As mentioned before, AWS Lambda can’t install the node_modules for us, so we need to assure they are located correctly before creating our zip file.
3. ZIP
The project needs to be zipped in the required structure, without the parent directory. The easiest way I found to do it, is to run the following command from the project root:
$ (cd dist && zip -r ../function.zip .)
The zip is now ready for deployment.
Deploy using Github Actions
The deployment part will be done using appleboy/lambda-action, and can be easily substituted with a corresponding AWS CLI command, which comes preinstalled on Github Actions CI machines.
Here’s a detailed example of a Github action:
name: Deploy
on:
push:
branches: [ master ]
jobs:
deploy:
runs-on: ubuntu-latest
steps:
- name: Checkout Code
uses: actions/checkout@v2
- name: Install Dependencies
run: yarn
# build command should be set in your package.json scripts as: "build": "tsc"
- name: Build
run: yarn build
- name: Move node_modules to dist
run: mv node_modules dist/node_modules
- name: Zip
run: (cd dist && zip -r ../function.zip .)
- name: Deploy to AWS
uses: appleboy/lambda-action@master
with:
aws_access_key_id: ${{ secrets.AWS_ACCESS_KEY_ID }}
aws_secret_access_key: ${{ secrets.AWS_SECRET_ACCESS_KEY }}
aws_region: ${{ secrets.AWS_REGION }}
function_name: my-cool-function
zip_file: function.zip
That’s it! Your Lambda is now ready for work.
We post tutorials like this weekly on Aspecto blog!
Check out one of our latest tutorials - How to Send Large SQS/SNS Messages with Node.js
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