Use dotenvx with Render

Use dotenvx with Render

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 a 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

Build and run it with Docker.

docker build -t app . && docker run -it --init --rm -p 3000:3000 app
docker container

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 to 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"]

Add production environment

Create a .env.production file 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="0354d5293e40f78b8b44d6b5ded92719ef99d119a79093d6babd0ef9e80a9a7667"

# .env.production
HELLO="encrypted:BGo+chylmSbkHeDsn9gPy5LYvYUUpTstaUr8hDU0lgp4ssyH2MXav43ww+B3WNaYLZQpJdJdJ2F8qLbV4vDolF42ETQFu/xxhKA2/MRxiC/Vd1s/DMDjm9RSHOCQ5YHywLrUY9UySesbn58="

.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="3c54363a4a678042d298660e2038df68aaa4a9383048d913d0e6db15e137020d"

We're ready to inject the encrypted .env.production secrets into Docker run.

Set decryption key

Set DOTENV_PRIVATE_KEY_PRODUCTION on Docker using the production key in your .env.keys file.

docker build -t app . && docker run -e "DOTENV_PRIVATE_KEY_PRODUCTION=3c54363a4a678042d298660e2038df68aaa4a9383048d913d0e6db15e137020d" -it --init --rm -p 3000:3000 app

Your docker instance starts and env is successfully injected using the encrypted contents of .env.production.

[[email protected]] injecting env (2) from .env.production
Server running on port:3000

For Render, do the same. Set your DOTENV_PRIVATE_KEY_PRODUCTION in the environment variable manager.

render.com

Visit your url and it says Hello production.

docker container

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.

dotenvx set HELLO Mot

Commit .env.production safely to code and re-run your Docker container.