[DPE-7796] Tweak Terraform modules

.github/workflows/ci.yaml

@@ -24,7 +24,22 @@ on:
 jobs:
   lint:
     name: Lint
-    uses: canonical/data-platform-workflows/.github/workflows/[email protected]
+    runs-on: ubuntu-latest
+    timeout-minutes: 5
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v5
+      - name: Install terraform
+        run: |
+          sudo snap install terraform --classic
+      - name: Install tox & poetry
+        run: |
+          pipx install tox
+          pipx install poetry
+      - name: Run linters
+        run: |
+          tox run -e lint
+          tox run -e lint-terraform
 
   unit-test:
     name: Unit test charm

.gitignore

@@ -145,4 +145,8 @@ build
 # local pyright settings
 pyrightconfig.json
 
+# Terraform
+.terraform
+.terraform.lock.hcl
+
 wt*/

docs/how-to/deploy/terraform.md

@@ -1,32 +1,30 @@
-# How to deploy using Terraform
 
-[Terraform](https://www.terraform.io/) is an infrastructure automation tool to provision and manage resources in clouds or data centers. To deploy Charmed MySQL K8s using Terraform and Juju, you can use the [Juju Terraform Provider](https://registry.terraform.io/providers/juju/juju/latest). 
+# How to deploy using Terraform
 
-The easiest way is to start from [these examples of terraform modules](https://github.com/canonical/terraform-modules) prepared by Canonical. This page will guide you through a deployment using an example module for MySQL on Kubernetes.
+[Terraform](https://www.terraform.io/) is an infrastructure automation tool to provision and manage resources in clouds or data centers.
+To deploy Charmed MySQL using Terraform and Juju, you can use the [Juju Terraform Provider](https://registry.terraform.io/providers/juju/juju/latest). 
 
 For an in-depth introduction to the Juju Terraform Provider, read [this Discourse post](https://discourse.charmhub.io/t/6939).
 
-```{note}
-**Note**: Storage support was added in [Juju Terraform Provider version 0.13+](https://github.com/juju/terraform-provider-juju/releases/tag/v0.13.0).
-```
-
 ## Install Terraform tooling
 
-This guide assumes Juju is installed and you have a K8s controller already bootstrapped. For more information, check the [Charmed MySQL K8s tutorial](/tutorial/index).
+This guide assumes Juju is installed, and you have a K8s controller already bootstrapped. For more information, check the [Charmed MySQL K8s tutorial](/tutorial/index).
 
 Let's install Terraform Provider and example modules:
 ```shell
 sudo snap install terraform --classic
 ```
+
 Switch to the K8s provider and create a new model:
 ```shell
 juju switch microk8s
 juju add-model my-model
 ```
-Clone examples and navigate to the MySQL machine module:
+
+Clone the MySQL K8s operator repository and navigate to the terraform module:
 ```shell
-git clone https://github.com/canonical/terraform-modules.git
-cd terraform-modules/modules/k8s/mysql
+git clone https://github.com/canonical/mysql-k8s-operator.git
+cd terraform
 ```
 
 Initialise the Juju Terraform Provider:
@@ -36,35 +34,18 @@ terraform init
 
 ## Verify the deployment
 
-Open the `main.tf` file to see the brief contents of the Terraform module:
-
-```tf
-resource "juju_application" "k8s_mysql" {
-  name  = var.mysql_application_name
-  model = var.juju_model_name
-  trust = true
-
-  charm {
-    name    = "mysql-k8s"
-    channel = var.mysql_charm_channel
-  }
-
-  units = 1
-}
-```
-
-Run `terraform plan` to get a preview of the changes that will be made:
+Open the `main.tf` file to see the brief contents of the Terraform module, and run `terraform plan` to get a preview of the changes that will be made:
 
 ```shell
-terraform plan -var "juju_model_name=my-model"
+terraform plan -var "model_name=my-model"
 ```
 
 ## Apply the deployment
 
 If everything looks correct, deploy the resources (skip the approval):
 
 ```shell
-terraform apply -auto-approve -var "juju_model_name=my-model"
+terraform apply -auto-approve -var "model_name=my-model"
 ```
 
 ## Check deployment status
@@ -78,48 +59,47 @@ juju status --model k8s:my-model --watch 1s
 Sample output:
 
 ```shell
-Model      Controller      Cloud/Region        Version  SLA          Timestamp
-my-model   k8s-controller  microk8s/localhost  3.5.3    unsupported  12:37:25Z
+Model     Controller      Cloud/Region         Version  SLA          Timestamp
+my-model  k8s-controller  microk8s/localhost   3.5.3    unsupported  12:37:25Z
 
 App        Version                  Status  Scale  Charm      Channel     Rev  Address         Exposed  Message
-mysql-k8s  8.0.36-0ubuntu0.22.04.1  active      1  mysql-k8s  8.0/stable  153  10.152.183.112  no
+mysql-k8s  8.0.41-0ubuntu0.22.04.1  active      1  mysql-k8s  8.0/stable  255  10.152.183.112  no
 
 Unit          Workload  Agent  Address     Ports  Message
 mysql-k8s/0*  active    idle   10.1.77.76         Primary
-
 ```
 
 Continue to operate the charm as usual from here or apply further Terraform changes.
 
 ## Clean up
 
-To keep the house clean, remove the newly deployed Charmed MySQL K8s by running
+To keep the house clean, remove the newly deployed MySQL K8s charm by running
 ```shell
-terraform destroy -var "juju_model_name=my-model"
+terraform destroy -var "model_name=my-model"
 ```
 
 Sample output:
 ```shell
-juju_application.k8s_mysql: Refreshing state... [id=terra-k8s:mysql-k8s]
+juju_application.mysql_server: Refreshing state... [id=my-model:mysql-k8s]
 
 Terraform used the selected providers to generate the following execution plan. Resource actions are indicated with the following symbols:
   - destroy
 
 Terraform will perform the following actions:
 
-  # juju_application.k8s_mysql will be destroyed
-  - resource "juju_application" "k8s_mysql" {
+  # juju_application.mysql_server will be destroyed
+  - resource "juju_application" "mysql_server" {
       - constraints = "arch=amd64" -> null
-      - id          = "terra-k8s:mysql-k8s" -> null
-      - model       = "terra-k8s" -> null
+      - id          = "my-model:mysql-k8s" -> null
+      - model       = "my-model" -> null
       - name        = "mysql-k8s" -> null
       - placement   = "" -> null
       - storage     = [
           - {
               - count = 1 -> null
-              - label = "database-1" -> null
+              - label = "database" -> null
               - pool  = "kubernetes" -> null
-              - size  = "1G" -> null
+              - size  = "10G" -> null
             },
         ] -> null
       - trust       = true -> null
@@ -129,32 +109,28 @@ Terraform will perform the following actions:
           - base     = "[email protected]" -> null
           - channel  = "8.0/stable" -> null
           - name     = "mysql-k8s" -> null
-          - revision = 153 -> null
+          - revision = 255 -> null
           - series   = "jammy" -> null
         }
     }
 
 Plan: 0 to add, 0 to change, 1 to destroy.
 
 Changes to Outputs:
-  - application_name = "mysql-k8s" -> null
+  - application_name = "mysql" -> null
 
 Do you really want to destroy all resources?
   Terraform will destroy all your managed infrastructure, as shown above.
   There is no undo. Only 'yes' will be accepted to confirm.
 
   Enter a value: yes
 
-juju_application.k8s_mysql: Destroying... [id=terra-k8s:mysql-k8s]
-juju_application.k8s_mysql: Destruction complete after 0s
+juju_application.mysql_server: Destroying... [id=my-model:mysql-k8s]
+juju_application.mysql_server: Destruction complete after 0s
 
 Destroy complete! Resources: 1 destroyed.
 ```
----
-
-```{note}
-For more examples of Terraform modules for K8s, see the other directories in the [`terraform-modules` repository](https://github.com/canonical/terraform-modules/tree/main/modules/k8s).
-```
 
-Feel free to [contact us](/reference/contacts) if you have any question and [collaborate with us on GitHub](https://github.com/canonical/terraform-modules)!
+---
 
+Feel free to [contact us](/reference/contacts) if you have any question and collaborate with us on GitHub!

terraform/main.tf

@@ -1,21 +1,19 @@
-resource "juju_application" "k8s_mysql" {
+resource "juju_application" "mysql_server" {
   name  = var.app_name
-  model = var.juju_model_name
-  trust = true
+  model = var.model_name
 
   charm {
     name     = "mysql-k8s"
+    base     = var.base
     channel  = var.channel
     revision = var.revision
-    base     = var.base
   }
 
   storage_directives = {
     database = var.storage_size
   }
 
-  units       = var.units
-  constraints = var.constraints
   config      = var.config
-  resources   = var.resources
+  constraints = var.constraints
+  units       = var.units
 }

terraform/outputs.tf

@@ -1,20 +1,23 @@
-output "application_name" {
-  value = juju_application.k8s_mysql.name
+output "app_name" {
+  description = "Name of the MySQL Server K8s application"
+  value       = juju_application.mysql_server.name
 }
 
-
 output "provides" {
+  description = "Map of all the provided endpoints"
   value = {
-    database          = "database",
-    metrics_endpoint  = "metrics-endpoint",
+    database          = "database"
     grafana_dashboard = "grafana-dashboard"
+    metrics_endpoint  = "metrics-endpoint"
   }
 }
 
 output "requires" {
+  description = "Map of all the required endpoints"
   value = {
-    logging       = "logging"
     certificates  = "certificates"
     s3_parameters = "s3-parameters"
+    logging       = "logging"
+    tracing       = "tracing"
   }
 }

terraform/variables.tf

@@ -1,58 +1,52 @@
-variable "juju_model_name" {
-  description = "Juju model name"
+variable "model_name" {
+  description = "Juju model to deploy to"
   type        = string
 }
 
 variable "app_name" {
-  description = "Name of the application in the Juju model."
+  description = "Name of the juju application"
   type        = string
   default     = "mysql-k8s"
 }
 
+variable "base" {
+  description = "Application base"
+  type        = string
+  default     = "[email protected]"
+}
+
+variable "config" {
+  description = "Application configuration. Details at https://charmhub.io/mysql-k8s/configurations"
+  type        = map(string)
+  default     = {}
+}
+
+variable "constraints" {
+  description = "Juju constraints for the application"
+  type        = string
+  default     = "arch=amd64"
+}
+
 variable "channel" {
-  description = "Charm channel to use when deploying"
+  description = "Charm channel to deploy from"
   type        = string
   default     = "8.0/stable"
 }
 
 variable "revision" {
-  description = "Revision number to deploy charm"
+  description = "Charm revision to deploy"
   type        = number
   default     = null
 }
 
-variable "base" {
-  description = "Application base"
-  type        = string
-  default     = "[email protected]"
-}
-
 variable "units" {
   description = "Number of units to deploy"
   type        = number
-  default     = 1
-}
-
-variable "constraints" {
-  description = "Juju constraints to apply for this application."
-  type        = string
-  default     = "arch=amd64"
+  default     = 3
 }
 
 variable "storage_size" {
   description = "Storage size"
   type        = string
   default     = "10G"
 }
-
-variable "config" {
-  description = "Application configuration. Details at https://charmhub.io/mysql-k8s/configurations"
-  type        = map(string)
-  default     = {}
-}
-
-variable "resources" {
-  description = "Resources to use with the application"
-  type        = map(string)
-  default     = {}
-}

terraform/versions.tf

@@ -1,9 +1,10 @@
 terraform {
   required_version = ">= 1.6.6"
+
   required_providers {
     juju = {
       source  = "juju/juju"
-      version = ">= 0.14.0"
+      version = ">= 0.20.0, < 1.0.0"
     }
   }
 }

tox.ini

@@ -9,6 +9,7 @@ env_list = lint, unit
 src_path = "{tox_root}/src"
 tests_path = "{tox_root}/tests"
 scripts_path = "{tox_root}/scripts"
+terraform_path = "{tox_root}/terraform"
 all_path = {[vars]src_path} {[vars]tests_path} {[vars]scripts_path}
 
 [testenv]
@@ -41,6 +42,16 @@ commands =
     poetry run ruff format --check --diff {[vars]all_path}
     find {[vars]all_path} -type f \( -name "*.sh" -o -name "*.bash" \) -exec poetry run shellcheck --color=always \{\} +
 
+[testenv:lint-terraform]
+description = Check code against Terraform style standards
+allowlist_externals =
+    {[testenv]allowlist_externals}
+    terraform
+commands =
+    terraform fmt -check -diff -recursive {[vars]terraform_path}
+    terraform -chdir={[vars]terraform_path} init -backend=false
+    terraform -chdir={[vars]terraform_path} validate
+
 [testenv:unit]
 description = Run unit tests
 commands_pre =