Use dotenvx with Fly
Use dotenvx with Fly
Find code examples for this guide on GitHub.
Initial setup
Install the necessary web server libraries in the language of your choice.
npm install express --save
Create a simple Hello World program.
// index.js
const express = require('express')
const app = express()
const PORT = process.env.PORT || 3000
app.get('/', (req, res) => {
res.send(`Hello ${process.env.HELLO || ''}`)
})
app.listen(PORT, () => {
console.log(`Server running on port:${PORT}`)
})
Create Dockerfile.
# Dockerfile
FROM node:20
WORKDIR /app
COPY package*.json ./
RUN npm install
COPY . .
EXPOSE 3000
CMD ["node", "index.js"]
Create .dockerignore.
.dockerignore
# .dockerignore
.env.keys
Create fly.toml.
[http_service]
internal_port = 3000
Commit that to code and deploy it to Fly.
flyctl launch
flyctl deploy
Once deployed, your app will say 'Hello [blank]' as it doesn't have a way to access the environment variable yet. Let's do that next.
Run dotenvx
Install dotenvx in your Dockerfile and prepend your app command with dotenvx run --.
# Dockerfile
FROM node:20
WORKDIR /app
# Install dotenvx
RUN curl -sfS https://dotenvx.sh/install.sh | sh
COPY package*.json ./
RUN npm install
COPY . .
EXPOSE 3000
# Prepend dotenvx run
CMD ["dotenvx", "run", "--", "node", "index.js"]
If you prefer, install directly form GitHub Releases or view the install.sh file before executing.
Add production environment
Create .env.production in the root of your project.
# .env.production
HELLO="production"
Encrypt production
dotenvx encrypt -f .env.production
Your .env.production file is now encrypted, and you have a .env.keys file.
.env.production
#/-------------------[DOTENV_PUBLIC_KEY]--------------------/
#/ public-key encryption for .env files /
#/ [how it works](https://dotenvx.com/encryption) /
#/----------------------------------------------------------/
DOTENV_PUBLIC_KEY_PRODUCTION="025a54defaeff32caa2bbe60537b88b5b89716eade6df08418d7a68f5c4f742be6"
# .env.production
HELLO="encrypted:BD+uttK9iBuXnfx6HukDK06IGk0pQARwivtxM+ZiePvhRxHyQL3UD0sf0ayLw/P5Y/BED//zRiTlUf6nENuu7QhNJ24g3uADfrDfhvYi/MOHjmfKyRiu+yOxSw6e+c0yRNukS+n8SxONnec="
.env.keys
#/------------------!DOTENV_PRIVATE_KEYS!-------------------/
#/ private decryption keys. DO NOT commit to source control /
#/ [how it works](https://dotenvx.com/encryption) /
#/----------------------------------------------------------/
# .env.production
DOTENV_PRIVATE_KEY_PRODUCTION="424d0ea072eb17c6bee9b4b42ff6333513cf128ea3d5d60ccf79246ca7c3f786"
You SHOULD commit .env.production to code. It is now encrypted, safe, and recommended to do so. But DO NOT commit .env.keys to code. Keep them somewhere safe like 1password or dotenvx ops.
We're ready to inject the encrypted .env.production secrets into the app on boot.
Set decryption key
Set DOTENV_PRIVATE_KEY_PRODUCTION on Fly using the production key in your .env.keys file. We'll use the fly cli, but you can also use their dashboard.
flyctl secrets set DOTENV_PRIVATE_KEY_PRODUCTION='424d0ea072eb17c6bee9b4b42ff6333513cf128ea3d5d60ccf79246ca7c3f786'
Redeploy.
flyctl deploy
Your app restarts and env is successfully injected using the encrypted contents of .env.production.
$ flyctl logs
[info] INFO Preparing to run: `docker-entrypoint.sh dotenvx run -- node index.js` as root
[info][[email protected]] injecting env (2) from .env.production
[info]Server running on port:3000
Visit your url and it says Hello production.
You succesfully add encryption to your .env files. This is safer than scattering your secrets across third-party platforms and tools. When you need to update a secret, run dotenvx set KEY value and redeploy.
Great job! That's pretty much it. See the bonus section(s) below to go a little deeper.
Bonus
Try changing the value of .env.production to your name.
npm run dotenvx -- set HELLO Mot -f .env.production
Commit .env.production safely to code and redeploy.
