feat: Immutability policy storage account [#IOPID-752] (#159)

Co-authored-by: Andrea Grillo <[email protected]>

postgres_flexible_server/tests/resources.tf

@@ -221,7 +221,10 @@ module "storage_account" {
   blob_delete_retention_days           = 7
   blob_change_feed_enabled             = true
   blob_change_feed_retention_in_days   = 10
-  blob_restore_policy_days             = 6
+  blob_storage_policy = {
+    blob_restore_policy_days   = 6
+    enable_immutability_policy = false
+  }
 
   tags = var.tags
 }

storage_account/README.md

@@ -90,6 +90,10 @@ resource "azurerm_private_dns_zone" "storage_account" {
 
 ```
 
+## Known Issues
+
+- Applying the immutability policy on an existing storage account fails due to a 404 NotFound error on the threat protection creation for the new storage. Solution, delete the resource and create the new one with the immutability policy.
+- Changing the `period_since_creation_in_days` will be updated in terraform state but not in the cloud provider resource. Solution, change the value using the Azure portal.
 
 ## Migration from v2
 
@@ -202,6 +206,7 @@ No modules.
 | [azurerm_advanced_threat_protection.this](https://registry.terraform.io/providers/hashicorp/azurerm/latest/docs/resources/advanced_threat_protection) | resource |
 | [azurerm_monitor_metric_alert.storage_account_low_availability](https://registry.terraform.io/providers/hashicorp/azurerm/latest/docs/resources/monitor_metric_alert) | resource |
 | [azurerm_storage_account.this](https://registry.terraform.io/providers/hashicorp/azurerm/latest/docs/resources/storage_account) | resource |
+| [null_resource.immutability](https://registry.terraform.io/providers/hashicorp/null/latest/docs/resources/resource) | resource |
 
 ## Inputs
 
@@ -218,14 +223,15 @@ No modules.
 | <a name="input_blob_change_feed_retention_in_days"></a> [blob\_change\_feed\_retention\_in\_days](#input\_blob\_change\_feed\_retention\_in\_days) | (Optional) The duration of change feed events retention in days. The possible values are between 1 and 146000 days (400 years). Setting this to null (or omit this in the configuration file) indicates an infinite retention of the change feed. | `number` | `null` | no |
 | <a name="input_blob_container_delete_retention_days"></a> [blob\_container\_delete\_retention\_days](#input\_blob\_container\_delete\_retention\_days) | Retention days for deleted container. Valid value is between 1 and 365 (set to 0 to disable). | `number` | `0` | no |
 | <a name="input_blob_delete_retention_days"></a> [blob\_delete\_retention\_days](#input\_blob\_delete\_retention\_days) | Retention days for deleted blob. Valid value is between 1 and 365 (set to 0 to disable). | `number` | `0` | no |
-| <a name="input_blob_restore_policy_days"></a> [blob\_restore\_policy\_days](#input\_blob\_restore\_policy\_days) | (Optional) Specifies the number of days that the blob can be restored, between 1 and 365 days. This must be less than the days specified for delete\_retention\_policy. | `number` | `0` | no |
+| <a name="input_blob_storage_policy"></a> [blob\_storage\_policy](#input\_blob\_storage\_policy) | Handle immutability policy for stored elements | <pre>object({<br>    enable_immutability_policy = bool<br>    blob_restore_policy_days   = number<br>  })</pre> | <pre>{<br>  "blob_restore_policy_days": 0,<br>  "enable_immutability_policy": false<br>}</pre> | no |
 | <a name="input_blob_versioning_enabled"></a> [blob\_versioning\_enabled](#input\_blob\_versioning\_enabled) | Controls whether blob object versioning is enabled. | `bool` | `false` | no |
 | <a name="input_cross_tenant_replication_enabled"></a> [cross\_tenant\_replication\_enabled](#input\_cross\_tenant\_replication\_enabled) | (Optional) Should cross Tenant replication be enabled? Defaults to false. | `bool` | `false` | no |
 | <a name="input_custom_domain"></a> [custom\_domain](#input\_custom\_domain) | Custom domain for accessing blob data | <pre>object({<br>    name          = string<br>    use_subdomain = bool<br>  })</pre> | <pre>{<br>  "name": null,<br>  "use_subdomain": false<br>}</pre> | no |
 | <a name="input_domain"></a> [domain](#input\_domain) | (Optional) Specifies the domain of the Storage Account. | `string` | `null` | no |
 | <a name="input_enable_identity"></a> [enable\_identity](#input\_enable\_identity) | (Optional) If true, set the identity as SystemAssigned | `bool` | `false` | no |
 | <a name="input_enable_low_availability_alert"></a> [enable\_low\_availability\_alert](#input\_enable\_low\_availability\_alert) | Enable the Low Availability alert. Default is true | `bool` | `true` | no |
 | <a name="input_error_404_document"></a> [error\_404\_document](#input\_error\_404\_document) | The absolute path to a custom webpage that should be used when a request is made which does not correspond to an existing file. | `string` | `null` | no |
+| <a name="input_immutability_policy_props"></a> [immutability\_policy\_props](#input\_immutability\_policy\_props) | Properties to setup the immutability policy. The resource can be created only with "Disabled" and "Unlocked" state. Change to "Locked" state doens't update the resource for a bug of the current module. | <pre>object({<br>    allow_protected_append_writes = bool<br>    period_since_creation_in_days = number<br>  })</pre> | <pre>{<br>  "allow_protected_append_writes": false,<br>  "period_since_creation_in_days": 730<br>}</pre> | no |
 | <a name="input_index_document"></a> [index\_document](#input\_index\_document) | The webpage that Azure Storage serves for requests to the root of a website or any subfolder. For example, index.html. The value is case-sensitive. | `string` | `null` | no |
 | <a name="input_is_hns_enabled"></a> [is\_hns\_enabled](#input\_is\_hns\_enabled) | Enable Hierarchical Namespace enabled (Azure Data Lake Storage Gen 2). Changing this forces a new resource to be created. | `bool` | `false` | no |
 | <a name="input_is_sftp_enabled"></a> [is\_sftp\_enabled](#input\_is\_sftp\_enabled) | Enable SFTP | `bool` | `false` | no |

storage_account/main.tf

@@ -37,9 +37,9 @@ resource "azurerm_storage_account" "this" {
       }
 
       dynamic "restore_policy" {
-        for_each = (var.blob_restore_policy_days == 0 ? [] : [1])
+        for_each = (var.blob_storage_policy.blob_restore_policy_days == 0 ? [] : [1])
         content {
-          days = var.blob_restore_policy_days
+          days = var.blob_storage_policy.blob_restore_policy_days
         }
       }
     }
@@ -81,10 +81,22 @@ resource "azurerm_storage_account" "this" {
     }
   }
 
+  dynamic "immutability_policy" {
+    for_each = var.blob_storage_policy.enable_immutability_policy ? [1] : []
+
+    content {
+      allow_protected_append_writes = var.immutability_policy_props.allow_protected_append_writes
+      state                         = "Unlocked"
+      period_since_creation_in_days = var.immutability_policy_props.period_since_creation_in_days
+    }
+  }
+
   # the use of storage_account_customer_managed_key resource will cause a bug on the plan: this paramenter will always see as changed.
+  # the state property is ignored because is overridden from a null_resource.
   lifecycle {
     ignore_changes = [
-      customer_managed_key
+      customer_managed_key,
+      immutability_policy.0.state
     ]
   }
 
@@ -134,3 +146,28 @@ resource "azurerm_monitor_metric_alert" "storage_account_low_availability" {
 
   tags = var.tags
 }
+
+resource "null_resource" "immutability" {
+
+  triggers = {
+    immutability_policy : var.blob_storage_policy.enable_immutability_policy
+    resouce_group_name : var.resource_group_name
+    name : var.name
+  }
+
+  provisioner "local-exec" {
+    command = <<EOT
+      if ${self.triggers.immutability_policy}; then
+        az storage account update --immutability-state Locked \
+          --resource-group ${self.triggers.resouce_group_name} \
+          --name ${self.triggers.name} \
+          --query "id"
+        # query is used to hide other properties from logging
+      fi
+    EOT
+  }
+
+  depends_on = [
+    azurerm_storage_account.this
+  ]
+}

storage_account/tests/resources.tf

@@ -24,7 +24,44 @@ module "storage_account" {
   blob_delete_retention_days           = 7
   blob_change_feed_enabled             = true
   blob_change_feed_retention_in_days   = 10
-  blob_restore_policy_days             = 6
+
+  blob_storage_policy = {
+    blob_restore_policy_days   = 6
+    enable_immutability_policy = false
+  }
+
+  tags = var.tags
+}
+
+module "storage_account_immutable" {
+  source = "../../storage_account"
+
+  name                            = replace("${local.project}-im-st", "-", "")
+  account_kind                    = "StorageV2"
+  account_tier                    = "Standard"
+  access_tier                     = "Hot"
+  account_replication_type        = "GRS"
+  resource_group_name             = azurerm_resource_group.rg.name
+  location                        = azurerm_resource_group.rg.location
+  advanced_threat_protection      = true
+  allow_nested_items_to_be_public = false
+  public_network_access_enabled   = true
+
+  blob_versioning_enabled              = true
+  blob_container_delete_retention_days = 7
+  blob_delete_retention_days           = 7
+  blob_change_feed_enabled             = true
+  blob_change_feed_retention_in_days   = 10
+
+  blob_storage_policy = {
+    blob_restore_policy_days   = 0
+    enable_immutability_policy = true
+  }
+
+  immutability_policy_props = {
+    allow_protected_append_writes = false
+    period_since_creation_in_days = 1
+  }
 
   tags = var.tags
 }

storage_account/variables.tf

@@ -97,12 +97,6 @@ variable "blob_change_feed_retention_in_days" {
   default     = null
 }
 
-variable "blob_restore_policy_days" {
-  description = "(Optional) Specifies the number of days that the blob can be restored, between 1 and 365 days. This must be less than the days specified for delete_retention_policy."
-  type        = number
-  default     = 0
-}
-
 variable "cross_tenant_replication_enabled" {
   description = "(Optional) Should cross Tenant replication be enabled? Defaults to false."
   type        = bool
@@ -163,6 +157,40 @@ variable "custom_domain" {
   }
 }
 
+# -------------------
+# Immutability Policy
+# -------------------
+
+variable "blob_storage_policy" {
+  type = object({
+    enable_immutability_policy = bool
+    blob_restore_policy_days   = number
+  })
+  description = "Handle immutability policy for stored elements"
+  default = {
+    enable_immutability_policy = false
+    blob_restore_policy_days   = 0
+  }
+
+  # https://learn.microsoft.com/en-us/azure/storage/blobs/point-in-time-restore-overview#limitations-and-known-issues
+  validation {
+    condition     = (var.blob_storage_policy.enable_immutability_policy == true && var.blob_storage_policy.blob_restore_policy_days == 0) || var.blob_storage_policy.enable_immutability_policy == false
+    error_message = "Immutability policy doesn't support Point-in-Time restore"
+  }
+}
+
+variable "immutability_policy_props" {
+  type = object({
+    allow_protected_append_writes = bool
+    period_since_creation_in_days = number
+  })
+  description = "Properties to setup the immutability policy. The resource can be created only with \"Disabled\" and \"Unlocked\" state. Change to \"Locked\" state doens't update the resource for a bug of the current module."
+  default = {
+    allow_protected_append_writes = false
+    period_since_creation_in_days = 730
+  }
+}
+
 
 # -------------------
 # Alerts variables

storage_account_customer_managed_key/tests/resources.tf

@@ -24,7 +24,10 @@ module "storage_account" {
   blob_delete_retention_days           = 7
   blob_change_feed_enabled             = true
   blob_change_feed_retention_in_days   = 10
-  blob_restore_policy_days             = 6
+  blob_storage_policy = {
+    blob_restore_policy_days   = 6
+    enable_immutability_policy = false
+  }
 
   enable_identity = true
 

storage_object_replication/tests/resources.tf

@@ -25,7 +25,10 @@ module "storage_account" {
   blob_delete_retention_days           = 7
   blob_change_feed_enabled             = true
   blob_change_feed_retention_in_days   = 10
-  blob_restore_policy_days             = 6
+  blob_storage_policy = {
+    blob_restore_policy_days   = 6
+    enable_immutability_policy = false
+  }
 
   tags = var.tags
 }