Express on AWS with SST
Create and deploy an Express app to AWS with SST.
We are going to build an app with Express, add an S3 Bucket for file uploads, and deploy it to AWS in a container with SST.
Before you get started, make sure to configure your AWS credentials.
Examples
We also have a few other Express examples that you can refer to.
1. Create a project
Let’s start by creating our Express app.
mkdir aws-express && cd aws-expressnpm init -ynpm install express
Init Express
Create your app by adding an index.mjs
to the root.
import express from "express";
const PORT = 80;
const app = express();
app.get("/", (req, res) => { res.send("Hello World!")});
app.listen(PORT, () => { console.log(`Server is running on http://localhost:${PORT}`);});
Init SST
Now let’s initialize SST in our app.
npx sst@latest initnpm install
This’ll create a sst.config.ts
file in your project root.
2. Add a Service
To deploy our Express app, let’s add an AWS Fargate container with Amazon ECS. Update your sst.config.ts
.
async run() { const vpc = new sst.aws.Vpc("MyVpc"); const cluster = new sst.aws.Cluster("MyCluster", { vpc });
new sst.aws.Service("MyService", { cluster, loadBalancer: { ports: [{ listen: "80/http" }], }, dev: { command: "node --watch index.mjs", }, });}
This creates a VPC with an ECS Cluster, and adds a Fargate service to it.
The dev.command
tells SST to instead run our Express app locally in dev mode.
Start dev mode
Run the following to start dev mode. This’ll start SST and your Express app.
npx sst dev
Once complete, click on MyService in the sidebar and open your Express app in your browser.
3. Add an S3 Bucket
Let’s add an S3 Bucket for file uploads. Add this to your sst.config.ts
below the Vpc
component.
const bucket = new sst.aws.Bucket("MyBucket");
Link the bucket
Now, link the bucket to the container.
new sst.aws.Service("MyService", { // ... link: [bucket],});
This will allow us to reference the bucket in our Express app.
4. Upload a file
We want a POST
request made to the /
route to upload a file to our S3 bucket. Let’s add this below our Hello World route in our index.mjs
.
app.post("/", upload.single("file"), async (req, res) => { const file = req.file; const params = { Bucket: Resource.MyBucket.name, ContentType: file.mimetype, Key: file.originalname, Body: file.buffer, };
const upload = new Upload({ params, client: s3, });
await upload.done();
res.status(200).send("File uploaded successfully.");});
Add the imports. We’ll use the extra ones below.
import multer from "multer";import { Resource } from "sst";import { Upload } from "@aws-sdk/lib-storage";import { getSignedUrl } from "@aws-sdk/s3-request-presigner";import { S3Client, GetObjectCommand, ListObjectsV2Command,} from "@aws-sdk/client-s3";
const s3 = new S3Client({});const upload = multer({ storage: multer.memoryStorage() });
And install the npm packages.
npm install multer @aws-sdk/client-s3 @aws-sdk/lib-storage @aws-sdk/s3-request-presigner
5. Download the file
We’ll add a /latest
route that’ll download the latest file in our S3 bucket. Let’s add this below our upload route in index.mjs
.
app.get("/latest", async (req, res) => { const objects = await s3.send( new ListObjectsV2Command({ Bucket: Resource.MyBucket.name, }), );
const latestFile = objects.Contents.sort( (a, b) => b.LastModified - a.LastModified, )[0];
const command = new GetObjectCommand({ Key: latestFile.Key, Bucket: Resource.MyBucket.name, }); const url = await getSignedUrl(s3, command);
res.redirect(url);});
Test your app
To upload a file run the following from your project root.
curl -F file=@package.json http://localhost:80/
This should upload the package.json
. Now head over to http://localhost:80/latest
in your browser and it’ll show you what you just uploaded.
5. Deploy your app
To deploy our app we’ll first add a Dockerfile
.
FROM node:lts-alpine
WORKDIR /app/
COPY package.json /appRUN npm install
COPY index.mjs /app
ENTRYPOINT ["node", "index.mjs"]
This just builds our Express app in a Docker image.
Let’s also add a .dockerignore
file in the root.
node_modules
Now to build our Docker image and deploy we run:
npx sst deploy --stage production
You can use any stage name here but it’s good to create a new stage for production. This’ll give the URL of your Express app deployed as a Fargate service.
✓ Complete MyService: http://jayair-MyServiceLoadBala-592628062.us-east-1.elb.amazonaws.com
Connect the console
As a next step, you can setup the SST Console to git push to deploy your app and monitor it for any issues.
You can create a free account and connect it to your AWS account.