Let’s dive into Terraform provider creation

A presentation at CfgMgmtCamp in February 2023 in Ghent, Belgium by Horacio Gonzalez

Aurélie Vache @aurelievache DevRel at Conferences organizer Tech visual articles & books Sketchnoter … & ❤ Retrogaming https://www.youtube.com/c/AurelieVache https://dev.to/aurelievache/ Les Productions de MOA

Horacio Gonzalez @LostInBrittany Spaniard lost in Brittany, developer, dreamer and all-around geek

OVHcloud: A global leader Web Cloud & Telcom 30 Data Centers in 12 locations 1 Million+ Servers produced since 1999 Private Cloud 34 Points of Presence on a 20 TBPS Bandwidth Network 1.5 Million Customers across 132 countries Public Cloud 2200 Employees worldwide 3.8 Million Websites hosting Storage 115K Private Cloud VMS running 1.5 Billion Euros Invested since 2016 300K Public Cloud instances running P.U.E. 1.09 Energy efficiency indicator 380K Physical Servers running in our data centers 20+ Years in Business Disrupting since 1999 Network & Security

Credit where it is due All the gophers you will see are drawn by Aurélie and Horacio, and are based on the Go mascot designed by Renee French which is licensed under CC BY 3.0.

Terraform becoming the de facto standard

Writing Terraform providers Defining new Terraform resources

Provider SDK https://developer.hashicorp.com/terraform/plugin/sdkv2

Installing Terraform providers $ terraform init Initializing provider plugins… - Finding terraform.local/local/myprovider versions matching “0.0.1”… - Installing terraform.local/local/myprovider v0.0.1…

Installing providers from registry $ vi provider.tf terraform { required_providers { thenamespace = { source = “thenamespace/myprovider” } } } If your provider is on the official registry at https://registry.terraform.io/providers/thenamespace/myprovider

Installing providers locally $ go build -o terraform-provider-myprovider $ mkdir -p ~/.terraform.d/plugins/terraform.local/local/myprovider/0.0.1/darwin_amd64 $ mv terraform-provider-myprovider ~/.terraform.d/plugins/terraform.local/local/myprovider/0.0.1/darwin_amd64

Installing providers locally $ vi provider.tf terraform { required_providers { thenamespace = { source = “terraform.local/local/myprovider” version = “0.0.1” } } }

Do I need a Terraform provider? If you have an API, you should have a Terraform provider

What do we want? ● In a simple and easy Terraform provider ● Handle cute Gophers ● In Go, because providers are made in Go 😁

Everything begins with an API https://github.com/scraly/gophers-api

For the demos we will use Gitpod Automated, ephemeral developer environments in the web

Everything begins with an API $ task swagger.serve task: [swagger.serve] swagger serve -F swagger ./pkg/swagger/swagger.yml —no-open 2022/10/31 20:16:51 serving docs at http://localhost:38457/docs

Everything begins with an API $ task run task: [run] GOFLAGS=-mod=mod go run internal/main.go 2022/10/30 20:22:05 Serving gophers API at http://[::]:8080 $ curl localhost:8080/gophers [{“name”:”5th-element”,”displayname”:”5th Element.png”,”url”:”https://raw.githubusercontent.com/scraly/gophers/main/5th-ele ment.png”}]

Gophers deserve to be seen https://github.com/LostInBrittany/gophers-api-watcher

Everything begins with an API $ curl -X POST localhost:8080/gopher -H “Content-Type: application/json” -d \ ‘{“name”:”yoda-gopher”,”displayname”:”Yodada Gopher”,”url”:”https://raw.githubusercontent.com/scraly/gophers/main/yoda-gopher. png”}’ $ curl -X DELETE localhost:8080/gopher?name=5th-element $ curl -X PUT localhost:8080/gopher \ -H “Content-Type: application/json” -d \ ‘{“name”:”yoda-gopher”,”displayname”:”Yoda Gopher”,”url”:”https://raw.githubusercontent.com/scraly/gophers/main/yoda-gopher. png”}’

Let’s create our provider! 1. Create the skeleton of our provider thanks to scaffolding https://github.com/hashicorp/terraform-provider-scaffolding

Let’s create our provider! https://github.com/scraly/terraform-provider-gophers

Test it! the provider $ vi provider.tf terraform { required_providers { gophers = { source = “terraform.local/local/gophers” version = “0.0.1” } } } provider “gophers” { endpoint = “http://myawesomeurl.com” }

Adding the schema “Translating” the Swagger into a Go schema

Test it! $ vi gophers_data.tf # List of available gophers data “gophers” “my_gophers” { } output “return_gophers” { value = length(data.gophers.my_gophers.gophers) >= 1 }

Test it! $ vi gopher_data.tf # Display information about a Gopher data “gophers_gopher” “moultipass” { name = “5th-element” }

Test it! $ vi gopher_resource.tf resource “gophers_gopher” “x-files” { name = “x-files” displayname = “X Files” url } = “https://raw.githubusercontent.com/scraly/gophers/main/x-files.png”

Testing the provider locally $ go build -o terraform-provider-gophers $ mkdir -p ~/.terraform.d/plugins/terraform.local/local/gophers/0.0.1/darwin_arm64 $ mv terraform-provider-gophers ~/.terraform.d/plugins/terraform.local/local/gophers/0.0.1/darwin_arm64 $ make install

Testing the provider locally $ rm .terraform.lock.hcl && terraform init $ terraform apply

Testing the provider locally $ terraform destroy

OVHcloud Terraform Provider To easily manage OVHcloud products

OVHcloud Terraform Provider https://registry.terraform.io/providers/ovh/ovh/latest/docs

OVHcloud Terraform Provider https://github.com/ovh/terraform-provider-ovh

Best practices But we have learnt with our providers

Doc is not optional $ tfplugindocs generate Generate the doc of your provider. Based on the schema the provider exposes. https://github.com/hashicorp/terraform-plugin-docs

Write useful examples in your doc Examples in your documentation should be: ● Useful ● Up-to-date ● Working Users will copy paste your examples! 😉

And… test your doc! Use the doc preview tool https://registry.terraform.io/tools/doc-preview

Acceptance tests $ make testacc $ make testacc TESTARGS=”-run TestAccDataSourceGopher”

Provider is a reflection of your API client Think about API first design

Use the logs for debugging $ TF_LOG=INFO terraform plan

Set timeouts / retry Timeouts: &schema.ResourceTimeout{ Create: schema. DefaultTimeout (20 * time.Minute), Update: schema. DefaultTimeout (20 * time.Minute), Delete: schema. DefaultTimeout (20 * time.Minute), }, Timeout/retry par resource

Read the code See how other open source providers are written

The “3 P” rule Practice, practice, practice

A handy cheat sheet https://github.com/scraly/terraform-cheat-sheet/

Thank you! https://bit.ly/tf-provider-cfgmgtcamp

We ❤ feedbacks https://bit.ly/vote-tf-provider-cfgmgtcamp

Horacio Gonzalez
@lostinbrittany

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Currently when we think of Infrastructure as Code (IaC), one tool seems to stand out and has become a de-facto standard: Terraform.

With Terraform you can easily build, edit and version your whole infrastructure by using Terraform builtin providers or custom ones.

But sometimes there is no provider for the infrastructure you intend to use, not even the lone no-star repository in a lost corner of the internet, only a custom REST API. What can you do? Going back to manual operations? Create your own scripts?

In this talk Horacio and Aurélie will show you, step by step, how to go from an infrastructure API to a fully functional yet light Terraform provider. By taking as base a REST API, they will explain the basics of provider creation, give some pointers on how to do a simple yet efficient provider architecture and show you the code and the provider in action.

Will they succeed in this new mission?

Let’s dive into Terraform provider creation

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