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The Dhall Configuration Language

dhall-lang.org

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Re: The Dhall Configuration Language

#61

Post by eru »

doliveira wrote: post #37
svnpenn wrote: post #5

{ home = "/home/bill" , privateKey = "/home/bill/.ssh/id_ed25519" , publicKey = "/home/blil/.ssh/id_ed25519.pub" } This is the most awkward abuse of formatting I've seen in a long time. Just allow/require a final trailing comma, and this nonsense goes away

Yeah, I also really dislike this mixing up of indentation levels because of a language limitation. The "{" denotes a container, and the "," a separation between items of said container, for me it makes sense for them to be nested a level deeper

That's one way to interpret things, but not the only way.

In practice, this style reads just fine once you get used to it. Indentation is mostly there as a human convenience, so just has to work well with human brains (and be understood by a computer, if it's significant), but doesn't have to necessarily follow some abstract unified theory of syntax trees.

Re: The Dhall Configuration Language

#62

Post by chrisjharris »

fridental wrote: post #46

Why wouldn't you use Python as your configuration language?

Most of the time with configuration files, you want to be able to do at least basic validation on the config without having to run the whole piece of software. Python has no native typing, so there's nothing to stop the user from creating a configuration file where, for example, they have set a field that is intended to specify a port number, as a string. This error will become obvious when you run the software (and it presumably fails some way in) but for some use cases this is too late. With dhall you can specify that the field for the port number needs to not just be an integer, but be a natural number, so you're able to catch plenty of config errors nice and early, and can go some way to validating the config in isolation from the software it's intended to be used for.

Re: The Dhall Configuration Language

#64

Post by corrral »

cbb330 wrote: post #17
junon wrote: post #10

> Can you spot the mistake? Nope, so now I have no incentive to use your config format because it's established something is wrong and it's completely non-obvious. Thanks for not wasting my time, I guess.

This opinion is ironic because this is exactly what the author intended to describe -- the typo IS hard to find. The "Hello, World" example is nothing more than JSON, showing a string repeated 3 times. On the third time, "bill" is misspelled with "blil". The next tab shows how Dhall uses a variable definition to prevent this type of error.

I mean... from context, it's probably a mistake, but on the other hand we don't actually know the structure of that filesystem or the author's intentions.

Re: The Dhall Configuration Language

#65

Post by mihaitodor »

leetrout wrote: post #53
CameronNemo wrote: post #43

Earlier quoted context omitted.

I use tanka/jsonnet and cringe everytime I read a helm chart. Type safety would be nice, but the k8s api can verify the validity on the server. https://tanka.dev/

Tanka is what I want to use when the time comes. Are there any pitfalls you have learned to avoid?

I think it might still have issues figuring out that it needs to apply CRDs first: https://github.com/grafana/tanka/issues/246 Besides that, I found it super-handy for deploying https://github.com/prometheus-operator/prometheus-operator and https://github.com/kubernetes-monitoring/kubernetes-mixin

LE: The "garbage collection" feature is very interesting, but I didn't get to experiment with it enough yet: https://tanka.dev/garbage-collection

Re: The Dhall Configuration Language

#66

Post by mihaitodor »

dcchambers wrote: post #41

I work on a deployment tooling team. In 2019/2020 we did a deep dive into Dhall vs. Jsonnet^1 for standardizing config and kubernetes templating across my company (Zendesk). We ended up going with Jsonnet (although some Dhall evangelists in the company have kept the dream alive!), which I think is a more approachable language for many, but Dhall has a lot of cool features and good things going for it. Jsonnet is far…

> using a more traditional language like Go to solve some of our configuration/deployment and data templating problems.

Have you looked at https://github.com/kris-nova/naml ? :)

Re: The Dhall Configuration Language

#67

Post by aendruk »

lilyball wrote: post #44
aendruk wrote: post #27

Earlier quoted context omitted.

I too spent the whole time scrutinizing the syntax and ignoring the values, since this is an intro to the language and not to Bill’s dotfiles. I was ultimately unable to deduce the presumed syntax error and independently came to the same misconclusion.

It can't be a syntax error though as it evaluates successfully as demonstrated by the right-hand side.

In general, if you think that someone’s claimed experience doesn’t make sense, you’re probably just missing information.

On small viewports, the “right-hand side” is down page and off screen, and the instructions I’m following reference only tabs visible above.

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