Add support for time based rotation

README.md

@@ -171,7 +171,7 @@ Available targets:
 | <a name="input_label_order"></a> [label\_order](#input\_label\_order) | The order in which the labels (ID elements) appear in the `id`.<br>Defaults to ["namespace", "environment", "stage", "name", "attributes"].<br>You can omit any of the 6 labels ("tenant" is the 6th), but at least one must be present. | `list(string)` | `null` | no |
 | <a name="input_label_value_case"></a> [label\_value\_case](#input\_label\_value\_case) | Controls the letter case of ID elements (labels) as included in `id`,<br>set as tag values, and output by this module individually.<br>Does not affect values of tags passed in via the `tags` input.<br>Possible values: `lower`, `title`, `upper` and `none` (no transformation).<br>Set this to `title` and set `delimiter` to `""` to yield Pascal Case IDs.<br>Default value: `lower`. | `string` | `null` | no |
 | <a name="input_labels_as_tags"></a> [labels\_as\_tags](#input\_labels\_as\_tags) | Set of labels (ID elements) to include as tags in the `tags` output.<br>Default is to include all labels.<br>Tags with empty values will not be included in the `tags` output.<br>Set to `[]` to suppress all generated tags.<br>**Notes:**<br>  The value of the `name` tag, if included, will be the `id`, not the `name`.<br>  Unlike other `null-label` inputs, the initial setting of `labels_as_tags` cannot be<br>  changed in later chained modules. Attempts to change it will be silently ignored. | `set(string)` | <pre>[<br>  "default"<br>]</pre> | no |
-| <a name="input_max_image_count"></a> [max\_image\_count](#input\_max\_image\_count) | How many Docker Image versions AWS ECR will store | `number` | `500` | no |
+| <a name="input_max_image_count"></a> [max\_image\_count](#input\_max\_image\_count) | How many Docker Image versions AWS ECR will store. Only used when [count\_based\_rotation](#count\_based\_rotation) is true | `number` | `500` | no |
 | <a name="input_name"></a> [name](#input\_name) | ID element. Usually the component or solution name, e.g. 'app' or 'jenkins'.<br>This is the only ID element not also included as a `tag`.<br>The "name" tag is set to the full `id` string. There is no tag with the value of the `name` input. | `string` | `null` | no |
 | <a name="input_namespace"></a> [namespace](#input\_namespace) | ID element. Usually an abbreviation of your organization name, e.g. 'eg' or 'cp', to help ensure generated IDs are globally unique | `string` | `null` | no |
 | <a name="input_organizations_full_access"></a> [organizations\_full\_access](#input\_organizations\_full\_access) | Organization IDs to provide with full access to the ECR. | `list(string)` | `[]` | no |
@@ -190,6 +190,7 @@ Available targets:
 | <a name="input_stage"></a> [stage](#input\_stage) | ID element. Usually used to indicate role, e.g. 'prod', 'staging', 'source', 'build', 'test', 'deploy', 'release' | `string` | `null` | no |
 | <a name="input_tags"></a> [tags](#input\_tags) | Additional tags (e.g. `{'BusinessUnit': 'XYZ'}`).<br>Neither the tag keys nor the tag values will be modified by this module. | `map(string)` | `{}` | no |
 | <a name="input_tenant"></a> [tenant](#input\_tenant) | ID element \_(Rarely used, not included by default)\_. A customer identifier, indicating who this instance of a resource is for | `string` | `null` | no |
+| <a name="input_time_based_rotation"></a> [time\_based\_rotation](#time\_based\_rotation) | Set to true to filter image based on the `sinceImagePushed` count type. [max\_image\_count](#input\_max\_image\_count) coresponds to number of days before expiration | `bool` | `false` | no |
 | <a name="input_use_fullname"></a> [use\_fullname](#input\_use\_fullname) | Set 'true' to use `namespace-stage-name` for ecr repository name, else `name` | `bool` | `true` | no |
 
 ## Outputs

docs/terraform.md

@@ -59,7 +59,7 @@
 | <a name="input_label_order"></a> [label\_order](#input\_label\_order) | The order in which the labels (ID elements) appear in the `id`.<br>Defaults to ["namespace", "environment", "stage", "name", "attributes"].<br>You can omit any of the 6 labels ("tenant" is the 6th), but at least one must be present. | `list(string)` | `null` | no |
 | <a name="input_label_value_case"></a> [label\_value\_case](#input\_label\_value\_case) | Controls the letter case of ID elements (labels) as included in `id`,<br>set as tag values, and output by this module individually.<br>Does not affect values of tags passed in via the `tags` input.<br>Possible values: `lower`, `title`, `upper` and `none` (no transformation).<br>Set this to `title` and set `delimiter` to `""` to yield Pascal Case IDs.<br>Default value: `lower`. | `string` | `null` | no |
 | <a name="input_labels_as_tags"></a> [labels\_as\_tags](#input\_labels\_as\_tags) | Set of labels (ID elements) to include as tags in the `tags` output.<br>Default is to include all labels.<br>Tags with empty values will not be included in the `tags` output.<br>Set to `[]` to suppress all generated tags.<br>**Notes:**<br>  The value of the `name` tag, if included, will be the `id`, not the `name`.<br>  Unlike other `null-label` inputs, the initial setting of `labels_as_tags` cannot be<br>  changed in later chained modules. Attempts to change it will be silently ignored. | `set(string)` | <pre>[<br>  "default"<br>]</pre> | no |
-| <a name="input_max_image_count"></a> [max\_image\_count](#input\_max\_image\_count) | How many Docker Image versions AWS ECR will store | `number` | `500` | no |
+| <a name="input_max_image_count"></a> [max\_image\_count](#input\_max\_image\_count) | How many Docker Image versions AWS ECR will store. Only used when [count\_based\_rotation](#count\_based\_rotation) is true | `number` | `500` | no |
 | <a name="input_name"></a> [name](#input\_name) | ID element. Usually the component or solution name, e.g. 'app' or 'jenkins'.<br>This is the only ID element not also included as a `tag`.<br>The "name" tag is set to the full `id` string. There is no tag with the value of the `name` input. | `string` | `null` | no |
 | <a name="input_namespace"></a> [namespace](#input\_namespace) | ID element. Usually an abbreviation of your organization name, e.g. 'eg' or 'cp', to help ensure generated IDs are globally unique | `string` | `null` | no |
 | <a name="input_organizations_full_access"></a> [organizations\_full\_access](#input\_organizations\_full\_access) | Organization IDs to provide with full access to the ECR. | `list(string)` | `[]` | no |
@@ -78,6 +78,7 @@
 | <a name="input_stage"></a> [stage](#input\_stage) | ID element. Usually used to indicate role, e.g. 'prod', 'staging', 'source', 'build', 'test', 'deploy', 'release' | `string` | `null` | no |
 | <a name="input_tags"></a> [tags](#input\_tags) | Additional tags (e.g. `{'BusinessUnit': 'XYZ'}`).<br>Neither the tag keys nor the tag values will be modified by this module. | `map(string)` | `{}` | no |
 | <a name="input_tenant"></a> [tenant](#input\_tenant) | ID element \_(Rarely used, not included by default)\_. A customer identifier, indicating who this instance of a resource is for | `string` | `null` | no |
+| <a name="input_time_based_rotation"></a> [time\_based\_rotation](#time\_based\_rotation) | Set to true to filter image based on the `sinceImagePushed` count type. [max\_image\_count](#input\_max\_image\_count) coresponds to number of days before expiration | `bool` | `false` | no |
 | <a name="input_use_fullname"></a> [use\_fullname](#input\_use\_fullname) | Set 'true' to use `namespace-stage-name` for ecr repository name, else `name` | `bool` | `true` | no |
 
 ## Outputs

examples/complete/variables.tf

@@ -1,5 +1,6 @@
 variable "region" {
-  type = string
+  type        = string
+  description = "AWS region"
 }
 
 variable "encryption_configuration" {

main.tf

@@ -65,12 +65,23 @@ locals {
   remove_old_image_rule = [
     {
       rulePriority = length(var.protected_tags) + 2
-      description  = "Rotate images when reach ${var.max_image_count} images stored",
-      selection = {
-        tagStatus   = "any"
-        countType   = "imageCountMoreThan"
-        countNumber = var.max_image_count
-      }
+      description = (
+        var.time_based_rotation ?
+        "Rotate images older than ${var.max_image_count} days old" :
+        "Rotate images when reach ${var.max_image_count} images stored"
+      )
+      selection = merge(
+        {
+          tagStatus = "any"
+          countType = (
+            var.time_based_rotation ?
+            "sinceImagePushed" :
+            "imageCountMoreThan"
+          )
+          countNumber = var.max_image_count
+        },
+        var.time_based_rotation ? { countUnit = "days" } : {}
+      )
       action = {
         type = "expire"
       }

variables.tf

@@ -46,6 +46,12 @@ variable "max_image_count" {
   default     = 500
 }
 
+variable "time_based_rotation" {
+  type        = bool
+  description = "Set to true to filter image based on the `sinceImagePushed` count type."
+  default     = false
+}
+
 variable "image_names" {
   type        = list(string)
   default     = []