Add the Terraform module

Signed-off-by: gatici <[email protected]>

.gitignore

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+*.idea
+.vscode/
+.coverage
+.tox/
 venv/
 build/
-*.charm
-.coverage
+tests/integration/*-tester/lib/
+
+# Python
+**/venv/**
+*.pyc
+.python-version
+.mypy_cache/
 __pycache__/
 *.py[cod]
-.tox
-.idea/
-tests/integration/*-tester/lib/
-.env
+
+# 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/CONTRIBUTING.md

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+# Contributing
+
+## Development environment
+
+### Prerequisites
+
+Make sure the following software and tools are installed in the development
+environment.
+
+- `microk8s`
+- `juju`
+- `terraform`
+
+### Prepare Development Environment
+
+Install Microk8s:
+
+```console
+sudo snap install microk8s --channel=1.27-strict/stable
+sudo usermod -a -G snap_microk8s $USER
+newgrp snap_microk8s
+```
+
+Enable `storage` plugin for Microk8s:
+
+```console
+sudo microk8s enable hostpath-storage
+```
+
+Install Juju:
+
+```console
+sudo snap install juju --channel=3.1/stable
+```
+
+Install Terraform:
+
+```console
+sudo snap install --classic terraform
+```
+
+Bootstrap the Juju Controller using Microk8s:
+
+```console
+juju bootstrap microk8s
+```
+
+Add a Juju model:
+
+```console
+juju add model <model-name>
+````
+
+### Terraform provider
+
+The Terraform module uses the Juju provider to provision Juju resources. Please refer to the [Juju provider documentation](https://registry.terraform.io/providers/juju/juju/latest/docs) for more information.
+
+A Terraform working directory needs to be initialized at the beginning.
+
+Initialise the provider:
+
+```console
+terraform init
+```
+
+## Testing
+
+Terraform CLI provides various ways to do formatting and validation.
+
+Formats to a canonical format and style:
+
+```console
+terraform fmt
+```
+
+Check the syntactical validation:
+
+```console
+terraform validate
+```
+
+Preview the changes:
+
+```console
+terraform plan
+```

terraform/README.md

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+# Grafana-agent-k8s Terraform Module
+
+This Grafana-agent-k8s Terraform module aims to deploy the [grafana-agent-k8s charm](https://charmhub.io/grafana-agent-k8s) via Terraform.
+
+## Getting Started
+
+### Prerequisites
+
+The following software and tools needs to be installed and should be running in the local environment.
+
+- `microk8s`
+- `juju 3.x`
+- `terrafom`
+
+### Deploy the grafana-agent-k8s charm using Terraform
+
+Make sure that `storage` plugin is enabled for Microk8s:
+
+```console
+sudo microk8s enable hostpath-storage
+```
+
+Add a Juju model:
+
+```console
+juju add model <model-name>
+```
+
+Initialise the provider:
+
+```console
+terraform init
+```
+
+Customize the configuration inputs under `terraform.tfvars` file according to requirement.
+
+Replace the values in the `terraform.tfvars` file:
+
+```yaml
+# Mandatory Config Options
+model_name = "put your model-name here"
+```
+
+Run Terraform Plan by providing var-file:
+
+```console
+terraform plan -var-file="terraform.tfvars" 
+```
+
+Deploy the resources, skip the approval:
+
+```console
+terraform apply -auto-approve 
+```
+
+### Check the Output
+
+Run `juju switch <juju model>` to switch to the target Juju model and observe the status of the application.
+
+```console
+juju status --relations
+```
+
+### Clean Up
+
+Remove the application:
+
+```console
+terraform destroy -auto-approve
+```

terraform/main.tf

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+resource "juju_application" "grafana-agent-k8s" {
+  name  = "grafana-agent-k8s"
+  model = var.model_name
+
+  charm {
+    name    = "grafana-agent-k8s"
+    channel = var.channel
+    base    = "[email protected]"
+  }
+  config = var.grafana-config
+  units  = 1
+  trust  = true
+}
+
+resource "juju_integration" "prometheus-remote-write" {
+  count = var.metrics_remote_write_offer_url != "" ? 1 : 0
+  model = var.model_name
+
+  application {
+    name     = juju_application.grafana-agent-k8s.name
+    endpoint = "send-remote-write"
+  }
+
+  application {
+    offer_url = var.metrics_remote_write_offer_url
+  }
+}
+
+resource "juju_integration" "loki-logging" {
+  count = var.logging_offer_url != "" ? 1 : 0
+  model = var.model_name
+
+  application {
+    name     = juju_application.grafana-agent-k8s.name
+    endpoint = "logging-consumer"
+  }
+
+  application {
+    offer_url = var.logging_offer_url
+  }
+}
+

terraform/outputs.tf

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+output "grafana_application_name" {
+  description = "Name of the deployed application."
+  value       = juju_application.grafana-agent-k8s.name
+}

terraform/terraform.tf

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+# Copyright 2023 Canonical Ltd.
+# See LICENSE file for licensing details.
+
+terraform {
+  required_providers {
+    juju = {
+      source  = "juju/juju"
+      version = "~> 0.10.1"
+    }
+  }
+}

terraform/terraform.tfvars

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+# Mandatory Config Options
+model_name = "put your model-name here"
+
+# Optional Configuration
+channel                        = "put the charm channel here"
+metrics_remote_write_offer_url = "Put the URL here"
+logging_offer_url              = "Put the URL here"
+grafana-config = {
+  tls_insecure_skip_verify = "put True not to skip the TLS verification"
+}

terraform/variables.tf

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+variable "model_name" {
+  description = "Name of Juju model to deploy application to"
+  type        = string
+  default     = ""
+}
+
+variable "channel" {
+  description = "The channel to use when deploying a charm "
+  type        = string
+  default     = "latest/stable"
+}
+
+variable "grafana-config" {
+  description = "Additional configuration for the Grafana"
+  default     = {}
+}
+
+variable "metrics_remote_write_offer_url" {
+  description = "Prometheus offer URL for `send-remote-write` endpoint"
+  type        = string
+  default     = ""
+}
+
+variable "logging_offer_url" {
+  description = "Loki offer URL for `logging-consumer` endpoint"
+  type        = string
+  default     = ""
+}