Add variable to manage repo lifecycle within TF

The new variable `manage_repo` will manage Helm repository lifecycle
automatically, adding, updating and deleting it from Helm repo list.

Useful for use on CI/CD pipelines.

Author: Samuel Crespo

README.md

@@ -88,18 +88,21 @@ module jenkins {
 |------|---------|
 | terraform | >= 0.13 |
 | helm | >= 2.0 |
+| null | >= 3.0 |
 
 ## Providers
 
 | Name | Version |
 |------|---------|
 | helm | >= 2.0 |
+| null | >= 3.0 |
 
 ## Inputs
 
 | Name | Description | Type | Default | Required |
 |------|-------------|------|---------|:--------:|
 | app | an application to deploy | `map(any)` | n/a | yes |
+| manage\_repo | Whether Helm repo should be added, updated and removed during Terraform execution | `bool` | `false` | no |
 | namespace | namespace where to deploy an application | `string` | n/a | yes |
 | repository | Helm repository | `string` | n/a | yes |
 | set | Value block with custom STRING values to be merged with the values yaml. | <pre>list(object({<br>    name  = string<br>    value = string<br>  }))</pre> | `null` | no |

main.tf

@@ -1,3 +1,31 @@
+resource "null_resource" "repo_add" {
+  count = var.manage_repo ? 1 : 0
+
+  triggers = {
+    always_run = "${timestamp()}"
+  }
+
+  provisioner "local-exec" {
+    command = "helm repo add ${var.app["chart"]} ${var.repository}"
+  }
+}
+
+resource "null_resource" "repo_update" {
+  count = var.manage_repo ? 1 : 0
+
+  triggers = {
+    always_run = "${timestamp()}"
+  }
+
+  provisioner "local-exec" {
+    command = "helm repo update ${var.app["chart"]}"
+  }
+
+  depends_on = [
+    resource.null_resource.repo_add[0]
+  ]
+}
+
 resource "helm_release" "this" {
   count                      = var.app["deploy"] ? 1 : 0
   namespace                  = var.namespace
@@ -44,4 +72,25 @@ resource "helm_release" "this" {
       value = item.value.value
     }
   }
+
+  depends_on = [
+    resource.null_resource.repo_update
+  ]
+}
+
+resource "null_resource" "repo_delete" {
+  count = var.manage_repo ? 1 : 0
+
+  triggers = {
+    always_run = "${timestamp()}"
+  }
+
+  provisioner "local-exec" {
+    command = "helm repo remove ${var.app["chart"]}"
+  }
+
+  depends_on = [
+    resource.null_resource.repo_add[0],
+    resource.helm_release.this
+  ]
 }

variables.tf

@@ -36,3 +36,9 @@ variable "repository" {
   description = "Helm repository"
   type        = string
 }
+
+variable "manage_repo" {
+  description = "Whether Helm repo should be added, updated and removed during Terraform execution"
+  default     = false
+  type        = bool
+}

versions.tf

@@ -3,5 +3,6 @@ terraform {
 
   required_providers {
     helm = ">= 2.0"
+    null = ">= 3.0"
   }
 }