Why we created Taxi, and why we felt the need for another schema language

https://orbitalhq.com/blog/2023-05-12-why-we-created-taxi

by martypitt • 3 years ago

59 26 3 years ago

obi1kenobi• 3 years ago

I've had my eye on Taxi for a while, and it's neat! I agree that the problems it aims to solve are real and painful in real life.

In my experience, I'm not sure people care about schemas or schema languages — they are just implementation details best left under the hood. This is why in my own work, I started on the query end of the spectrum instead.

This is why I built Trustfall, a query engine able to query any data source: DBs, APIs, files like PDF, CSV, or JSON, or any combination of those.

GitHub: https://github.com/obi1kenobi/trustfall

Playground showing the query "which GitHub/Twitter users comment on HackerNews stories about OpenAI?": https://play.predr.ag/hackernews#?f=1&q=IyBDcm9zcyBBUEkgcXVl...

martypitt7• 3 years ago

I agree that querying is where the real value is at, and Trustfall looks like an elegant approach.

While Taxi is all about documenting & augmenting specs, Orbital is the query engine (which is a bit similar to Trustfall) that consumes those specs.

Orbital's goal is to allow consumers to be able to query for data, without having to be aware of the specifics of the data sets / APIs / DBs, etc they're composing together.

IMO GraphQL does a nice job on the query side of keeping consumers away from the wiring, but shifts the obligation to middleware resolvers.

How data is wired together is ultimately an implementation detail, and one that changes. If consumers need to know about how stuff is connected, they're subject to breakages when those details change.

gavinray• 3 years ago

  > GraphQL does a nice job on the query side of keeping consumers away from the wiring, but shifts the obligation to middleware resolvers.

I'm not sure that I understand how Orbital is different from tools that autogenerate GraphQL API's on top of data sources like databases and API's.

From the site, it reads:

  > "Orbital uses your existing API specs and Database schemas - enriched with Taxi metadata to describe links. Orbital turns this into rich API and data catalog, letting you explore all your data, and how it connects."

It sounds like the same concept, except using a new language instead of GraphQL?

The schema language looks very similar to something AWS has called Smithy by the way:

- https://aws.amazon.com/blogs/developer/introducing-smithy-id...

- https://smithy.io/2.0/index.html

nextaccountic• 3 years ago

Orbital is the query engine

So I searched and

https://github.com/orbitalapi/orbital says to use https://hub.docker.com/r/orbitalhq/orbital which has no README

It also says "This repository will contain our open source code, along with issues, discussions and roadmap.", is there an ETA for source code release?

Will the Java application in that docker container be open sourced?

sfvisser• 3 years ago

Couldn’t quickly find it, but does it support enums/sum types?

martypitt7• 3 years ago

Enums, yep: https://taxilang.org/language-reference/types-and-models/#en...

Sum types, no, not yet.

hurril• 3 years ago

The examples all look like something I can do today in any modern functional language. What if I told you that you do not have to stick with Java or C#?

hhthrowaway1230• 3 years ago

i love how graphql described its types in its dsl, thats one of things id love to see carried over in other schema formats. it looks like taxi tries to do this to some extend

martypitt7• 3 years ago

A descriptive type system is a big part of what makes Taxi work.

We took a lot of inspiration from GraphQL (because it's awesome), but I actually think we go further in the type system than GraphQL.

dang2• 3 years ago

I think there was a related thread about this in recent weeks but I can't find it. Anyone?

martypitt7• 3 years ago

Taxi was discussed 12 months ago here:

https://news.ycombinator.com/item?id=31524950

dang2• 3 years ago

That's the one I was looking for. Thanks!

Taxi: A language for documenting data models and the contracts of APIs - https://news.ycombinator.com/item?id=31524950 - May 2022 (36 comments)

philipodonnell• 3 years ago

Taxi shifts the obligation of describing how things stitch together from Consumers to Producers. Traditionally, it falls to consumers to work out how to do this. And, it’s an expensive question to answer… it involves tracking down API specs, reading docs, and building a mental model of how things hang together.

I work on enterprise data platforms and this project sounds very much like the "data mesh" concept where responsibility for defining metadata/usability of datasets is supposed to rest with the teams producing the datasets rather than the teams consuming datasets. The same criticism probably applies:

* Even though it is expensive/slow for a consumer to figure out how to use data, it is even more expensive/slow to have producers try to continuously anticipate the needs of all possible current and future consumers, rather than focus on their system and have actual consumers figure out how to use the subset of data they need as it changes.

* Above a Dunbar-esque-sized organization you can no longer rely on empathy to encourage producers to expend extra effort on consumer's needs, so either monetary or disciplinary encouragement is needed, both of which raise costs even further.

Is there a name for this kind of paradox? When an approach will work only in a company below a certain size/complexity/age, but that kind of company probably doesn't feel the pain enough to need the approach?

martypitt7• 3 years ago

it is even more expensive/slow to have producers try to continuously anticipate the needs of all possible current and future consumers

I agree, but I don't think Taxi encourages that. (I sure hope it doesn't).

All that's really happening is defining a system-agnostic set of terms, embedding those in producer schemas, and then letting consumers using those same terms to ask for data.

Those terms can be used to automate integration, and in many (but not all) cases, alleviate the need for low-value plumbing code.

Semantic Metadata is a growing trend in the data ecosystem (cube.dev is doing a nice job here too). The Agile folks have had Ubiquitous Language as a first class concept since day dot.

an approach will work only in a company below a certain size/complexity/age I think that GraphQL federation is an example of mid-to-large companies trying to solve the federation problem, suggesting they both feel the pain, and are looking for solutions.

mst• 3 years ago

The goals of Taxi feel at least somewhat like 'creating a domain driven design style Ubiquitous Language to describe data and relationships' and the deliberate not-forcing-a-single-global-thing seems like it'll at least make it harder for enterprise dysfunction to bend it into having the failure modes the grandparent describes.

cgio• 3 years ago

What happens when a consumer does not understand the producer’s domain and misuses the data? As we load metadata with semantics of their own, we just kick the can down the road. Metadata is itself semantics about data. In many regulated environments, as producer you are responsible for downstream aggregations etc. I think the idea works great in prototyping, but similar to data mesh, ownership is poorly defined in the presence of aggregate domains and it’s more tuned to operational point to point interfaces.

seanhunter• 3 years ago

   > Even though it is expensive/slow for a consumer to figure out how to use data, it is even more expensive/slow to have producers try to continuously anticipate the needs of all possible current and future consumers, rather than focus on their system and have actual consumers figure out how to use the subset of data they need as it changes.

I agree completely on the speed impact but I would go further and say this is basically impossible. I have worked on data everywhere from small to massive enterprises and the only model I have ever see work at a large enterprise is for source systems to just produce data in a raw-ish format that comes out of their system and leave it to the people who need to consume that data to figure out how to massage it into whatever format they need.

The reasons I think it's not possible for upstream to anticipate are:

1) Analytic usecases multiply as systems do and as users start consuming data. As soon as you start using data to address problems in the org, you see more and more questions you would like to use data to address. There is no way for a producer system to forsee all the possible analytic questions people would like to answer using their data, especially as data analysis is a creative endeavour and peoples' imagination is pretty amazing (especially taken collectively).

2) As data sources multiply, the analytical possibilities of combining these data sources explode quadratically. There is no way for any single upstream system to anticipate how this will go.

What upstream systems need to do is produce all the data they can from their system and let users do what they do when combining. You can make some sensible guidelines available (eg "document what the columns mean", "keep up to date estimates of volumes to expect", "have a data sample/staging system/test instance for people to integrate against", "put your goddam timestamps into UTC wherever possible" etc) that aren't too onerous for upstream maintainers to follow if they want to be good citizens.

AlexITC• 3 years ago

Not sure if others are aware, there is an Esoteric language called Taxi (https://esolangs.org/wiki/Taxi).

swalsh• 3 years ago

This is super interesting, it's like a single spec for your entire enterprise architecture.

davidy123• 3 years ago

It's a shame they didn't mention Hydra. https://www.hydra-cg.com/spec/latest/core/

This is designed to let data be exchanged richly between sites, and comes from the earliest ideas of the web, it is the HATEOAS part of REST.

speedbird• 3 years ago

ASN.1 anybody?

RideAndWave• 3 years ago

Yeah, it's a common problem with non deterministic api schemas, e.g. openapi and swagger (https://swagger.io/specification/), but Taxi looks similar in some aspects to protoforce (https://www.protoforce.io/) except that the types subset is substantially narrower.

nimrody• 3 years ago

Can you explain what's non-deterministic about swagger/open-api?

malkia• 3 years ago

How do you extend this later, when you need getReviews(id: FilmId, somethingElse) : FilmReview[], andSomethingElse[] ?

   service ReviewsApi {
       @HttpOperation(method = "GET", url = "https://reviews/{id}")
       operation getReviews(id: FilmId): FilmReview[]
   }

Why we created Taxi, and why we felt the need for another schema language

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