Comment by Too

3 years ago

Terraforms HCL is well designed.

I know a lot of people hate it but I find it to be the only configuration language that makes any sense for moderately large configs.

It’s short, readable, unambiguous, great IDE support. Got built in logic, variables, templates, functions and references to other resources - without being Turing complete imperative language, and without becoming a xml monstrosity.

Seriously there is nothing even close to it. Tell me one reasonable alternative in wide use that’s not just some preprocessor bolted onto yaml, like Helm charts or Ansible jinja templates.

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Too

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randomswede  3 years ago

There's a world of difference between "simple configuration needs" and "complex configuration needs".

I will take a kubernetes deployment manifest as an example that you would want to express in a hypothetically perfect configuration language. Now, eventueally, you end up in the "containers" bit of the pod template inside the deployment spec.

And in that, you can (and arguably should) set resources. But, in an ideal world, when you set a CPU request (or, possibly, limit, but I will go with request for now) for an image that has a Go binary in it, you probably also want to have a "GOMAXPROCS" environment variable added that is the ceiling of your CPU allocation. And if you add a memory limit, and the image has a Java binary in it, you probably want to add a few of the Java memory-tuning flags.

And it is actually REALLY important that you don't repeat yourself here. In the small, it's fine, but if you end up in a position where you need to provide more, or less, RAM or CPU, on short notice (because after all, configuration files drive what you have in production, and mutating configuration is how you solve problems at speed, when you have an outage), any "you have to carefully put the identical thing in multiple places" is exactly how you end up with shit not fixing themselves.

So, yeah, as much hate as it gets, BCL may genuinely be better than every other configuration language I have had the misfortune to work with. And one of the things I looked forward to, when I left the G, was to never ever in my life have to see or think about BCL ever again. And then I saw what the world at large are content with. It is bloody depressing is what it is.