How to read Heroku's nested process.env vars / object in nconf? - heroku

Question

I'm trying to deploy Ghost 1.2.0 to Heroku. With previous versions of Ghost (<= 0.11.x), they used a config.js file where you could just do:
database: {
client: 'postgres',
connection: {
host: process.env.POSTGRES_HOST,
user: process.env.POSTGRES_USER,
password: process.env.POSTGRES_PASSWORD,
database: process.env.POSTGRES_DATABASE,
port: process.env.POSTGRES_PORT
},
debug: false
}, …
But in this version they're using nconf that replaces this config.js for environment dependent JSON files like config.production.json.
JSON files unlike JS objects can't have vars as values. I could hardcode my credentials to the JSON file, but I don't want to do that because:
Looks like a bad practise to me, and
Heroku rotates credentials periodically and updates applications where this database is attached. (Quoted from Heroku)
After some digging into nconf README and issues I understood that it would be possible to imitate this expected database object just with:
nconf.env({
separator: '__' // Two dashes
});
and defining vars as:
heroku config:set DATABASE__CLIENT=postgres
heroku config:set DATABASE__CONNECTION__HOST=<value>
...
but, no matter what, I get undefined when I later call:
nconf.get('database');
nconf.get('DATABASE'); // In case it was case-sensitive...
Instead, if I call:
nconf.get('DATABASE__CLIENT'); // postgres
it works. I could try (and I will) to modify Ghost scripts to read all variables this way, but as long as it expects a database object it'll be so cool to get it working the right way.
So, has anybody figured out how to correctly recreate an object with Heroku's env vars?

Answer 1

I've finally found the solution.
Unless you want to modify nconf.env(settings) like:
nconf.env({
separator: '__', // Two dashes
lowerCase: true
});
This will make it possible to pass lowerCase: true to env() so that if an environment variable is called SOMETHING or SOMEthing, it will also be gettable using something [Source]
I recommend to use already lowercase env vars.
So,
heroku config:set database__client=postgres
will be readable using:
nconf.get('database:client');
Looks like nconf has a different character separator to define nested variables called separator and another one to read them called logicalSeparator (its default value is :)