terraform-provider-restapi VS openapi-generator

Hi folks,

My company has an OpenAPI3 spec. We have a community supported Terraform provider that we are moving in-house soon.

I was wondering why there is no easy way to generate a Terraform provider from an OpenAPI spec?

There's no open issue in the generator project[0].

Some googling turned up a couple of projects[1],[2], but they only support Swagger; OpenAPI is the successor to Swagger. There is some progress on supporting OpenAPI[3]. I also found this provider, which is a thin wrapper around REST calls[4].

It's not discussed very much on the Terraform forum[5].

Either I'm missing the need for this or underestimating the difficulty.

0: https://github.com/OpenAPITools/openapi-generator/issues?q=is%3Aissue+is%3Aopen+terraform

1: https://www.logicmonitor.com/blog/how-to-write-a-custom-terraform-provider-automatically-with-openapi

2: https://github.com/dikhan/terraform-provider-openapi

3: https://github.com/dikhan/terraform-provider-openapi/pull/320

4: https://github.com/Mastercard/terraform-provider-restapi

5: https://discuss.hashicorp.com/t/sdk-provider-development-anyone-ever-used-code-generation-or-other-tools-to-simplify-their-provider-development/20301/2

Unless CloudFormation has some way to work with external systems? In my case I wasn't even using a built-in Terraform provider, but a REST API provider which calls our external service's API.

There is also Mastercard/Rest provider which IMHO results in a bit more natural HCL2 syntax.

I've used https://github.com/Mastercard/terraform-provider-restapi successfully with a cloud provider which provides a suitable HTTP API. There was a bit of fiddling with JSON formatting and their API docs, but it wasn't too hard all in all.

But like you say - now I've done that, I want to do it for every UI that I'm forced to log in to!

Disclaimer: We're an early adopter of Stainless at Mux.

I've spent more of my time than I'd like to admit managing both OpenAPi spec files [1] and fighting with openapi-generator [2] than any sane person should have to. While it's great having the freedom to change the templates an thus generated SDKs you get with using that sort of approach, it's also super time consuming, and when you have a lot of SDKs (we have 6 generated SDKs), in my experience it needs someone devoted to managing the process, staying up with template changes etc.

Excited to see more SDK languages come to Stainless!

[1] https://www.mux.com/blog/an-adventure-in-openapi-v3-api-code...

[2] https://github.com/OpenAPITools/openapi-generator

As a result, the following specification can be used to generate clients in a number of different languages via OpenAPI Generator.

Of course you can compile the server from source if you have Go and the OpenAPI generator JAR (https://github.com/OpenAPITools/openapi-generator?tab=readme...)

Follow these steps : https://github.com/c100k/rebootx-on-prem/blob/master/.github...

And then :

(cd ./impl/http-server-go && GOARCH=amd64 GOOS=openbsd go build -o /app/rebootx-on-prem-http-server-go-openbsd-amd64 -v)

By adapting the arch if needed. Not tested, but it should work.

TL;DR: Start generating your HTTP clients and all the DTOs of the requests and responses automatically from your API, using openapi-generator instead of writing your own.

As an alternative, you can also use the official OpenAPI Generator, which is a more generic tool supporting a wide range of languages and frameworks.

I trialed generating SDKs using the OpenAPI Generator package, which was largely unsatisfactory.

If Swagger/OpenAPI is available, save yourself a lot of trouble and generate the client using OpenAPI Generator. If not, use a library like RestEase to make it significantly easier to create the client.

For a run of the mill REST API you should generate OpenAPI (Swagger) info for the API using a library like NSwag or Swashbuckle. You'd want to do this no matter what because it's documentation for the API, but the bonus is that you can use it with tools like OpenAPI Generator to create API client code and models in a variety of languages. You certainly can create an API client library manually, it would entail having a nuget package with a class library that contains the models and client code for calling the endpoints (which I'd create using a lib such as RestEase unless you just enjoy writing boilerplate code by hand). However 95% of the time it simply isn't worth creating your own lib when OpenAPI is available because once you've done it a time or two it takes less than 5 min to run the generator and create (or update) a lib.

Then you can use oapi-codegen or openapi-generator to generate the Go (or other language) SDK for it.