dd-trace-rb VS contracts.ruby

This action starts two Ruby on Rails APIs, one instrumented with ddtrace and another with OpenTelemetry SDK, both connecting to an OpenTelemetry Collector that sends data to Jaeger:

Thing is, once you have 1) and 2), the added complexity of bringing in, integrating, and writing for a different tool to achieve 3) begins to make little sense, when you can just go along and do it just as well in rspec anyway... It's a matter of balance and heavily depends on the project.

> if you're still at Datadog

As a matter of fact I am. Feel free to shoot me an email.

    curl -s https://github.com/DataDog/dd-trace-rb/commit/176c642ca73679cabc5fa1a113bc9b600aa04dcd.patch | grep '^From:'

> For myself, I'm fine with the typing being in a separate .rbs file

We type[0] by having one separate .rbs file per .rb file. Works really well with an editor's vertical splits: type outline on one side, code on the other. That, or use something like vim-projectionist[1].

[0]: (WIP: there's a huge codebase to type, but we're progressively getting there) https://github.com/DataDog/dd-trace-rb/tree/master/sig

[1]: https://github.com/tpope/vim-projectionist

Thanks! I'll pass it on to the team :D

I've got to say, the folks at Intercom made it particularly fun. They were sending us traces and graphs from their internal systems when we trying to figure out some issues with them (e.g. we ran into this datadog context problem: https://github.com/DataDog/dd-trace-rb/issues/1389)

I had written a code contracts library for Ruby about 10 years ago [1]. I stopped working on it, mainly because it only provided runtime type checking, and I wanted static type checking. Nowadays my main language is typescript. I miss ruby, but can't give up the static typing that typescript provides. I really wish Ruby had a type system with the same level of support. VSCode has phenomenal TS support, and there's a community adding types to projects [2]. This is something I'd like for Ruby also.

> An integral part of this informality is relying on Matz’s taste and intuition for everything that affects the language’s core.

I think a more defined process would mean a better future for Ruby and Ruby developers.

- [1] https://github.com/egonschiele/contracts.ruby

- [2] https://github.com/DefinitelyTyped/DefinitelyTyped

Contracts gem can be a nice middle-ground. It has a fairly readably syntax and only checks method inputs and outputs at runtime. We use it to annotate important core methods, while leaving the rest type-free.

For example contracts gem needs to have a separate version/branch for ruby 3.x due to the breaking change above

This gives me access to input values as long as I defined them via attr_reader. Oh what's the Contract XXX above attr_reader? They are from contracts.ruby and completely optional and won't be explained in this post. You can safely ignore those and maybe study that gem later.