Why are we templating YAML? (2019) • Hacker News Board

Re: Why are we templating YAML? (2019)

#381

Post by _ea1k » Tue, Jan 23, 2024, 4:28 PM UTC

dygd wrote: post #52

ManBeardPc wrote: post #4

Worse yet, in some places (CI/CD) YAML becomes nearly a programming language. A very verbose, unintuitive, badly specified and vendor-specific one as well.

Spot on. We use ytt[0], "a slightly modified version of the Starlark programming language which is a dialect of Python". Burying logic somewhere in a yaml template is one thing I dislike with passion. [0] https://tanzu.vmware.com/developer/guides/ytt-gs/

TBH, ytt is the only yaml templating approach that I actually like.

The downside is that it is easy to do dumb things and put a lot of loops in your yaml.

The positive is that it is pretty easy to use it like an actual templating language with business logic in starlark files that look almost just like Python. In practice this works pretty well.

The syntax is still fairly clumsy, but I like it more than helm.

Re: Why are we templating YAML? (2019)

#382

Post by layer8 » Tue, Jan 23, 2024, 4:29 PM UTC

magicalhippo wrote: post #227

Redoubts wrote: post #202

Earlier quoted context omitted.

> And forbidding it makes a one-keystroke action a two or four one. You can’t be serious

For code I'd agree. However for configuration files, I find that I often need to edit them in places or environments where I don't have anything but the most bare-bones editor.

When this happens, I copy four spaces and then use Ctrl+V for Tab.

Yes, it’s not exactly the same due to alignment, and yes you have to repeat it after using the clipboard for other purposes, but it’s good enough for that occasional use.

Re: Why are we templating YAML? (2019)

#383

Post by _ea1k » Tue, Jan 23, 2024, 4:29 PM UTC

torginus wrote: post #109

armchairhacker wrote: post #38

To me YAML seems like the CoffeeScript of JSON, and unlike CoffeeScript I don’t understand why people are still using it. I guess XML and JSON are too verbose. But YAML is so far in the opposite direction, we get the same surprise conversions we’ve had in Excel ( https://ruudvanasseldonk.com/2023/01/11/the-yaml-document-fr... ). Why is “on” a boolean literal (of course so are “true”, “false”, as well as “yes”, “no”,…

Dunno, to me YAML is the python of markup languages. YAML is decent at handling things like nesting and arrays, while TOML sucks at it. I don't dislike YAML that much. That being said, we knew since the dawn of C macros that templating languages which are not aware of syntax, are AWFUL. Likewise, writing Helm charts (the place I encountered YAML templating) is just horrible, but would be so much nicer is templates re…

Yeah, that's why I prefer ytt over helm syntax. It isn't great syntax, but at least it is aware of what it is doing.

Having said that, yaml has some pretty obvious mistakes. It should have been a lot more prescriptive about data types. Not doing that creates a lot of unneeded confusion and weird bugs.

Re: Why are we templating YAML? (2019)

#384

Post by sspiff » Tue, Jan 23, 2024, 4:29 PM UTC

switch007 wrote: post #179

donalhunt wrote: post #106

Earlier quoted context omitted.

I've seen memes where SREs complain they have just become YAML engineers. :(

I mean...building a data centre / PaaS with YAML is pretty cool We used to have to shove servers in to racks ! Kids these days :D

I *loved* shoving servers in racks!

Re: Why are we templating YAML? (2019)

#385

Post by cyanydeez » Tue, Jan 23, 2024, 4:29 PM UTC

drybjed wrote: post #379

YAML, TOML and JSON can be ingested to represent the same data structures internally, it's just a few lines of code to decide which load() function should we use for a particular file. Why not support all three formats in your applications for configuration and just let users decide, which one they want to use? Put a 'config.json' in '/etc/app/conf.d/' and you get the same data, as with 'config.yml' or 'config.toml'.…

clarification: YAML and TOML can represent JSON, but the opposite isn't true.

Re: Why are we templating YAML? (2019)

#386

Post by deathanatos » Tue, Jan 23, 2024, 4:30 PM UTC

ManBeardPc wrote: post #4

Worse yet, in some places (CI/CD) YAML becomes nearly a programming language. A very verbose, unintuitive, badly specified and vendor-specific one as well.

Yeah … for CI files (like Github workflows & such), one of the best things I think I've done is just to immediately exec out to a script or program. That is, most of our CI steps look like this:

  run: 'exec ci/some-program'

… and that's it. It really aids being able to run the (failing) CI step offline, too, since it's a single script.

Stuff like Ansible is another matter altogether. That really is programming in YAML, and it hurts.

Re: Why are we templating YAML? (2019)

#387

Post by hosh » Tue, Jan 23, 2024, 4:30 PM UTC

This article is not convincing me about yaml or json templating.

The only thing I can think of is that generating these files requires picking a language platform. I chose Ruby to generate the k8s manifests I need.

If you are picking something that is meant to be language-agnostic, or to have very little ramp-up time, then sure, templating. It just comes at a cost where the templating language itself approaches that of a full blown, Turing-complete language as more features gets added, often with shaky foundations (such as HCL).

Re: Why are we templating YAML? (2019)

#388

Post by MrDarcy » Tue, Jan 23, 2024, 4:30 PM UTC

drybjed wrote: post #379

YAML, TOML and JSON can be ingested to represent the same data structures internally, it's just a few lines of code to decide which load() function should we use for a particular file. Why not support all three formats in your applications for configuration and just let users decide, which one they want to use? Put a 'config.json' in '/etc/app/conf.d/' and you get the same data, as with 'config.yml' or 'config.toml'.…

I tried this, it significantly complicated documentation and support after release. Lots more logic handling conflicting cases in two otherwise identical files, etc.

Re: Why are we templating YAML? (2019)

#389

Post by hosh » Tue, Jan 23, 2024, 4:31 PM UTC

armchairhacker wrote: post #38

To me YAML seems like the CoffeeScript of JSON, and unlike CoffeeScript I don’t understand why people are still using it. I guess XML and JSON are too verbose. But YAML is so far in the opposite direction, we get the same surprise conversions we’ve had in Excel ( https://ruudvanasseldonk.com/2023/01/11/the-yaml-document-fr... ). Why is “on” a boolean literal (of course so are “true”, “false”, as well as “yes”, “no”,…

YAML, or TOML or Json, I think the more problematic issue is using templating at all instead of generating them.

Re: Why are we templating YAML? (2019)

#390

Post by gtirloni » Tue, Jan 23, 2024, 4:31 PM UTC

I think we're barking at the wrong tree here (speaking about Kubernetes workloads).

This ugly mess of low-ish level details will never go away. Developers that are trying to focus on developing apps will never enjoy these things and that's fine.

Something like score.dev which abstracts things even further seems to be the way to go as the interface that is exposed to developers.