feat: Add the Terraform module - apply Gulsum's changes (#355)

##Feature
Adding the Terraform module for the mongodb-operator charm.

---------

Co-authored-by: Mehdi-Bendriss <[email protected]>
Co-authored-by: Gulsum Atici <[email protected]>

.github/workflows/ci.yaml

@@ -39,6 +39,7 @@ jobs:
         run: python3 -m pip install tox
       - name: Run tests
         run: tox run -e unit
+
   lib-check:
     name: Check libraries
     runs-on: ubuntu-latest
@@ -54,6 +55,37 @@ jobs:
           credentials: "${{ secrets.CHARMHUB_TOKEN }}" # FIXME: current token will expire in 2023-07-04
           github-token: "${{ secrets.GITHUB_TOKEN }}"
 
+jobs:
+  check-terraform:
+    name: Check Terraform
+    runs-on: ubuntu-latest
+    defaults:
+      run:
+        working-directory: ./terraform
+
+    steps:
+      - name: Checkout Repository
+        uses: actions/checkout@v4
+
+      - name: Setup Terraform
+        uses: hashicorp/setup-terraform@v3
+
+      - name: Initialize Terraform Module
+        run: terraform init
+
+      - name: Validate Terraform Module
+        run: terraform validate -no-color
+
+      - name: Validate terraform fmt
+        run: |
+          set +e 
+          terraform fmt -recursive -check -diff
+          FMT_STATUS="$?"
+          if [[ "$FMT_STATUS" -ne 0 ]]; then
+            echo "❌ terraform fmt failed" >> "$GITHUB_STEP_SUMMARY"
+          fi
+          exit "$FMT_STATUS"
+
   build:
     strategy:
       matrix:

.gitignore

@@ -1,8 +1,54 @@
-venv/
-build/
-*.charm
-.tox/
+*.idea
 .vscode/
 .coverage
+.tox/
+venv/
+build/
+
+# Python
+**/venv/**
+*.pyc
+.python-version
+.mypy_cache/
 __pycache__/
 *.py[cod]
+
+# Charmcraft
+*.charm
+
+# Local .terraform directories
+**/.terraform/*
+
+# .tfstate files
+*.tfstate
+*.tfstate.*
+
+# Crash log files
+crash.log
+crash.*.log
+
+# Exclude all .tfvars files, which are likely to contain sensitive data, such as
+# password, private keys, and other secrets. These should not be part of version
+# control as they are data points which are potentially sensitive and subject
+# to change depending on the environment.
+*.tfvars
+*.tfvars.json
+
+# Ignore override files as they are usually used to override resources locally and so
+# are not checked in
+override.tf
+override.tf.json
+*_override.tf
+*_override.tf.json
+
+# Include override files you do wish to add to version control using negated pattern
+# !example_override.tf
+
+# Include tfplan files to ignore the plan output of command: terraform plan -out=tfplan
+# example: *tfplan*
+
+# Ignore CLI configuration files
+.terraformrc
+terraform.rc
+.terraform.lock.hcl
+

terraform/README.md

@@ -0,0 +1,58 @@
+# MongoDB Operator Terraform module
+
+This folder contains a base [Terraform][Terraform] module for the `mongodb` charm.
+
+The module uses the [Terraform Juju provider][Terraform Juju provider] to model the charm deployment onto any Kubernetes environment managed by [Juju][Juju].
+
+The base module is not intended to be deployed in separation (it is possible though), but should rather serve as a building block for higher level modules.
+
+## Module structure
+
+- **main.tf** - Defines the Juju application to be deployed.
+- **variables.tf** - Allows customization of the deployment such as Juju model name, channel or application name and charm configuration.
+- **output.tf** - Responsible for integrating the module with other Terraform modules, primarily by defining potential integration endpoints (charm integrations), but also by exposing the application name.
+- **terraform.tf** - Defines the Terraform provider.
+
+## Using mongodb base module in higher level modules
+
+If you want to use `mongodb-operator` base module as part of your Terraform module, import it like shown below.
+
+```text
+module "mongodb-operator" {
+  source = "git::https://github.com/canonical/mongodb-operator.git/terraform"
+  
+  model_name = "juju_model_name"
+  
+  (Customize configuration variables here if needed)
+}
+```
+
+Please see the link to customize the Grafana configuration variables if needed.
+
+- [MongoDB configuration options][MongoDB configuration options]
+
+Create the integrations, for instance:
+
+```text
+resource "juju_integration" "amf-db" {
+  model = var.model_name
+
+  application {
+    name     = module.amf.app_name
+    endpoint = module.amf.database_endpoint
+  }
+
+  application {
+    name     = module.mongodb.app_name
+    endpoint = module.mongodb.database_endpoint
+  }
+}
+```
+
+Please check the available [integration pairs][integration pairs].
+
+[Terraform]: https://www.terraform.io/
+[Juju]: https://juju.is
+[Terraform Juju provider]: https://registry.terraform.io/providers/juju/juju/latest
+[MongoDB configuration options]: https://charmhub.io/mongodb/configure?channel=6/edge
+[integration pairs]: https://charmhub.io/mongodb/integrations?channel=6/edge

terraform/main.tf

@@ -0,0 +1,16 @@
+# Copyright 2024 Canonical Ltd.
+# See LICENSE file for licensing details.
+
+resource "juju_application" "mongodb" {
+  name  = var.app_name
+  model = var.model_name
+
+  charm {
+    name    = "mongodb"
+    channel = var.channel
+    base    = "[email protected]"
+  }
+  config = var.config
+  units  = 1
+  trust  = true
+}

terraform/outputs.tf

@@ -0,0 +1,67 @@
+# Copyright 2024 Canonical Ltd.
+# See LICENSE file for licensing details.
+
+output "app_name" {
+  description = "Name of the deployed application."
+  value       = juju_application.mongodb.name
+}
+
+# Provided integration endpoints
+
+output "database_endpoint" {
+  description = "Name of the endpoint to provide the mongodb_client interface."
+  value       = "database"
+}
+
+output "obsolete_endpoint" {
+  description = "Name of the endpoint to provide the mongodb interface."
+  value       = "obsolete"
+}
+
+output "cos_agent_endpoint" {
+  description = "Name of the endpoint to provide the cos_agent interface."
+  value       = "cos-agent"
+}
+
+output "config_server_endpoint" {
+  description = "Name of the endpoint to provide the shards interface."
+  value       = "config-server"
+}
+
+output "cluster_endpoint" {
+  description = "Name of the endpoint to provide the config-server interface."
+  value       = "cluster"
+}
+
+output "metrics_endpoint" {
+  description = "Name of the endpoint to provide the prometheus_scrape interface."
+  value       = "metrics-endpoint"
+}
+
+output "grafana_dashboard_endpoint" {
+  description = "Name of the endpoint to provide the grafana_dashboard interface."
+  value       = "grafana-dashboard"
+}
+
+output "logging_endpoint" {
+  description = "Name of the endpoint to provide the loki_push_api relation interface."
+  value       = "logging"
+}
+
+
+# Required integration endpoints
+
+output "certificates_endpoint" {
+  description = "Name of the endpoint to provide the tls-certificates interface."
+  value       = "certificates"
+}
+
+output "s3_credentials_endpoint" {
+  description = "Name of the endpoint to provide the s3 interface."
+  value       = "s3-credentials"
+}
+
+output "sharding_endpoint" {
+  description = "Name of the endpoint to provide the shards interface."
+  value       = "sharding"
+}

terraform/terraform.tf

@@ -0,0 +1,11 @@
+# Copyright 2024 Canonical Ltd.
+# See LICENSE file for licensing details.
+
+terraform {
+  required_providers {
+    juju = {
+      source  = "juju/juju"
+      version = "~> 0.10.1"
+    }
+  }
+}

terraform/variables.tf

@@ -0,0 +1,26 @@
+# Copyright 2024 Canonical Ltd.
+# See LICENSE file for licensing details.
+
+variable "model_name" {
+  description = "Name of Juju model to deploy application to"
+  type        = string
+  default     = ""
+}
+
+variable "app_name" {
+  description = "Name of the application in the Juju model"
+  type        = string
+  default     = "mongodb"
+}
+
+variable "channel" {
+  description = "The channel to use when deploying a charm"
+  type        = string
+  default     = "6/beta"
+}
+
+variable "config" {
+  description = "Additional configuration for the MongoDB. Details about available options can be found at https://charmhub.io/mongodb/configure?channel=6/beta."
+  type        = map(string)
+  default     = {}
+}