As I was looking into the environment variables documentation for App Platform, I could not understand what is meant by ${my-service.BINDABLE_NAME}. I’m using a nodejs server and trying to connect to the database on deploy. I tried process.env["database.HOSTNAME"] as a format but without success. I can’t for the life of me find these variables which are needed at deploy time (After starting the run command).

Thanks for your help

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1 answer

@gabrielbottari 👋

The bindable variables are meant to be used directly in the values of environment variables that you define for your app components.

For example, you may just want to define your own environment variable called DATABASE_URL with value of ${db.DATABASE_URL}. The bindable reference of ${db.DATABASE_URL} will be replaced with the actual values when your app is deployed. The db prefix here is the name of my database component, so this would reference one of your own components.

You can input these bindable references directly in the UI where you enter environment variables, or if you’re working with a raw app spec YAML, you can include them directly in there. This is an example from our sample-golang-notes repo:

name: sample-golang-notes
- name: web
    repo: digitalocean/sample-golang-notes
    branch: main
    value: ${db.DATABASE_URL}
- name: db
  engine: PG
  version: "12"

If your application code is in nodejs, then you would then access your environment variables as usual, depending on what name you’ve given them, with process.env.DATABASE_URL.

  • Hi @snormoredo,

    I am trying to set an env variable for my node.js/ app and I am trying to pass APP_URL to my client with the following:

    let socket = io.connect(process.env.APP_URL, {
        reconnection: false,
        transports: ['websocket'],
        upgrade: false

    I also tried with ${process.env.APP_URL} but I am receiving the following error:
    process is not defined

    Could you help me out?



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