Environment Variables in Production

A cursory glance at the code changes in the last section reveals that we have removed references to https://<your-app>.herokuapp.com, but have yet to replace this value. When require('dotenv').config() is invoked, no values will be appended to process.env since there is no .env file in the filesystem pushed to Heroku.

Different deployment strategies have different requirements for how environment variables are set. Deployment onto a remote Linux machine may require accessing the server via SSH and manualy creating a .env file in the remote environment. Containerized deployment often uses platform-specific configuation files -- such as docker-compose.yml for organizing the environment.

Heroku's platform-as-a-service solves deployed environment variables quite elegantly. Each Heroku application comes with a Settings page within Heroku's web UI for configuring variables. As well, the heroku CLI utility provides a one-line command for setting environment variables remotely.

Heroku Configuration Variables: Graphic Interface

Heroku uses the term "Config Vars", short for "configuation variables," to refer to environment variables. Config vars can be found within an application's Settings page.

Click "Reveal Config Vars" button to show all variables and reveal input fields to edit them. If there are no Config Vars, a descriptive message will be shown. In both cases, a developer can add a new configuration variable directly in this interface by entering a new KEY/VALUE pair and clicking "Add".

Empty list of Config vars

Feel free to use the graphic interface to set environment variables. The smartsite walkthrough details using Heroku's CLI to accomplish this task.

Heroku Config Vars: Command-Line Interface

The Heroku CLI allows developers to manage Heroku apps directly from the terminal. An application's config vars are accessible via the subcommand config. Issuing the command heroku config --help displays options for the subcommand.

command line

$ heroku config --help
display the config vars for an app

USAGE
  $ heroku config

OPTIONS
  -a, --app=app        (required) app to run command against
  -j, --json           output config vars in json format
  -r, --remote=remote  git remote of app to use
  -s, --shell          output config vars in shell format

COMMANDS
  config:edit   interactively edit config vars
  config:get    display a single config value for an app
  config:set    set one or more config vars
  config:unset  unset one or more config vars

1. Set a config var

Issue the command heroku config:set to set the NODE_ENV configuration variable to production. Next, check that the variable is set by issuing the command heroku config with no options.

Note: Remember what Heroku calls "config vars" are more provided to the running application as environment variables.

command line

$ heroku config:set NODE_ENV=production
$ heroku config

2. Set the Auth0 configuration

Use the sme process to set a config var for each of the Auth0 environment variables. The one variable which must be different from local configuration is AUTH0_BASE_URL. The example commands cover two methods of setting the variables: one at a time and many at once.

command line

$ heroku config:set AUTH0_BASE_URL=https://<your-app>.herokuapp.com
$ heroku config:set AUTH0_CALLBACK_ROUTE=/auth0/callback
$ heroku config:set AUTH0_CLIENT_ID=<your-client-id> AUTH0_ISSUER_BASE_URL=<your-issuer-url> AUTH0_SECRET=<your-secret>

Check that the variables are set by issuing the command heroku config with no options.

3. Deploy to Heroku

Now that the Heroku is aware of the environment variables the Node.js application requires, it is safe to deploy to Heroku without causing an application crash.

command line

$ git push heroku master
$ heroku open

After the deployment process, run heroku open to open the Heroku app. Test that all changes are successful by traversing the authentication flow. Navigate to the /env-vars route to see the programmed display messages.

Resources

Heroku config CLI: https://devcenter.heroku.com/articles/config-vars