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Discussion on: 7 Hardest Node.js Interview Questions & Answers

lietux profile image
Janne "Lietu" Enberg

You quote the "12 factors" as if it is your holy book, that alone is something to worry about.

Also the only real point that page has is:

A litmus test for whether an app has all config correctly factored out of the code is whether the codebase could be made open source at any moment, without compromising any credentials.

That doesn't mean or even hint at the need for environment variables, simply that your secrets and similar configuration isn't committed to your source in a human readable format. You CAN even commit your secrets and still pass that check, if you encrypt them so they can only be decrypted in the environment they're deployed to (often employed strategy e.g. when working with Salt Stack).

There is no reason secrets "must" be passed by environment variables. That might be a necessary strategy for the way you make your deployment, but not for everyone.

but then it means you will have to maintain it, like all of your code. I don't see what makes that a problem.

What I do often is commit a config that works for dev environment with a filename like config.example.*, and then simply deliver another config file for other deployments.

Additional concern is making sure your devs will have to spend minimal effort on fixing their environment, so it's even regularly worth symlinking or otherwise automating the use of your dev config in dev envs in a way that it doesn't accidentally get used on other environments if the config isn't properly created there.

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lietux profile image
Janne "Lietu" Enberg

One fun thing is when you specifically work with languages such as Python. If you have a file called settings.py which contains your settings coding against it is super easy from settings import PAYPAL_USER, and reconfiguring your app during unit testing is super convenient as you can just monkey patch the module.

This file can additionally of course have logic that reads environment variables into it, something like:

# settings.py
import sys
import os

PAYPAL_USER = "foo"
# ...

_l = dir(sys.modules[__name__])
for _key in os.environ:
    if _key in _l:
        setattr(sys.modules[__name__], _key, os.environ[_key])
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pawda profile image
Memoria

Regarding the config.example issue.

It is recognized as a bad practice because you're creating a file that is not requested anywhere and waiting to rot.

It falls as the same category as bad comments hinted by Robert C. Martin, Martin Fowler as well as others that have written on clean architecture and code.

Your devs will use their config.dev which is not committed so any time a new config need to be added or removed, there is no strong obligation to change the config.example file because everything will still work the way it is.

If you've ever work on projects with a big team either enterprise or open source. Many of projects using config.example simply doesn't work out of the box because of the config.example being just a piece of lies.

As for 12factors, well the 3rd point, says explicitly:

III. Config

Store config in the environment

I've mentioned the 12factors since the OP already mentioned it in another of his post.

Now without it being the holy grail or anything, it's a set of "best" practices that most if not nearly all recent IT books are derived from when they're talking about production ready code. Not having heard of it in 2018 is something to worry about.

@acostalima was asking if env was a best practice and you cannot deny him that.

You surely could do another way, a best practice doesn't mean the "one and only".

As you say is depends on your way of deployment. For example, if you're running on cloud providers like AWS, then use of secret manager makes a lot of sense for any secrets config.

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lietux profile image
Janne "Lietu" Enberg

Your devs will use their config.dev which is not committed

Um no, don't do that. Use a config that IS committed as the developer environment config, so when you add something to it you automatically set the correct value for all other devs.

Anyway, there is little point in continuing this.

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acostalima profile image
André Costa Lima

Thanks you both for your insights. 🙂