Deploying a TypeScript Express application to Fly

In this tutorial you will learn how to deploy a containerized TypeScript Express application to Fly.

The final code of this article can be found here.

#Prerequisites

• A Fly account
• A computer with Node.js, NPM, Docker, and Flyctl (the Fly CLI)

#Creating the application

npm init -y

npm install typescript ts-node @types/node --save-dev

npm install express
npm install @types/express --save-dev

tsconfig.json

{
  "compilerOptions": {
    "esModuleInterop": true,
    "outDir": "./dist"
  }
}

./src/application.ts

import express from "express";

const application = express();

const port = 8080;

application
  .get("/", (req, res) => {
    res.send({
      message: "Hello, World!",
    });
  })
  .get("/random", (req, res) => {
    res.send({
      number: Math.floor(Math.random() * 100),
    });
  });

application.listen(port, () => {
  console.log(`Application listening on port ${port}`);
});

To run the application locally:

npx ts-node ./src/application.ts

#Containerizing the application

Dockerfile

FROM node:17-alpine as build-image
WORKDIR /usr/src/app
COPY package*.json ./
COPY tsconfig.json ./
COPY ./src ./src
RUN npm ci
RUN npx tsc

FROM node:17-alpine
WORKDIR /usr/src/app
COPY package*.json ./
COPY --from=build-image ./usr/src/app/dist ./dist
RUN npm ci --production
COPY . .
EXPOSE 8080
CMD [ "node", "dist/application.js" ]

To build and run the container locally:

docker build . -t hello-world
docker run -dp 8080:8080 hello-world

#Deploying the application

1. fly launch to prepare your fly.toml file, containing your project settings. Inside the fly.toml file, ensure the service's internal_port (8080 by default) matches the port exposed by your container.
2. fly deploy to deploy your application.
3. fly open to open the deployed application in your browser.

#Cleaning up

fly destroy your-unique-app-id -y removes your application from the Fly platform.

That's all! Don't forget to delete the application once you're done testing.

The final code of this article can be found here.