Added secrets-manager module

infrastructure/modules/secrets-manager/README.md

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+# AWS Secrets Manager Terraform module
+
+Thin NHS wrapper around [terraform-aws-modules/secrets-manager/aws](https://registry.terraform.io/modules/terraform-aws-modules/secrets-manager/aws) that enforces the screening platform's baseline controls.
+
+## Hardcoded controls
+
+| Setting | Value | Reason |
+|---|---|---|
+| `block_public_policy` | `true` | Public access to secrets is never permitted |
+
+## Usage
+
+### Basic secret
+
+```hcl
+module "db_credentials" {
+  source = "../../modules/secrets-manager"
+
+  context     = module.this.context
+  stack       = "database"
+  name        = "db-credentials"
+  label_order = ["service", "environment", "stack", "name"]
+
+  description             = "RDS database credentials"
+  kms_key_id              = module.rds_kms.key_arn
+  recovery_window_in_days = 14
+
+  secret_string = jsonencode({
+    username = "admin"
+    password = var.db_password
+  })
+}
+```
+
+### Secret with a resource policy
+
+```hcl
+module "api_key" {
+  source = "../../modules/secrets-manager"
+
+  context = module.this.context
+  stack   = "api"
+  name    = "third-party-api-key"
+
+  description   = "API key for third-party integration"
+  secret_string = var.api_key
+
+  create_policy = true
+  policy_statements = {
+    allow_app_role = {
+      sid    = "AllowAppRoleRead"
+      effect = "Allow"
+      principals = [{
+        type        = "AWS"
+        identifiers = ["arn:aws:iam::123456789012:role/my-app-role"]
+      }]
+      actions   = ["secretsmanager:GetSecretValue"]
+      resources = ["*"]
+    }
+  }
+}
+```
+
+### Secret with rotation
+
+```hcl
+module "rotated_password" {
+  source = "../../modules/secrets-manager"
+
+  context = module.this.context
+  stack   = "database"
+  name    = "rotated-db-password"
+
+  description           = "Auto-rotated database password"
+  ignore_secret_changes = true  # let the rotation Lambda manage the value
+
+  enable_rotation     = true
+  rotation_lambda_arn = "arn:aws:lambda:eu-west-2:123456789012:function:rotate-db-secret"
+  rotation_rules = {
+    automatically_after_days = 30
+  }
+}
+```
+
+<!-- vale off -->
+<!-- markdownlint-disable -->
+<!-- BEGIN_TF_DOCS -->
+## Requirements
+
+| Name | Version |
+| ---- | ------- |
+| <a name="requirement_terraform"></a> [terraform](#requirement\_terraform) | >= 1.13 |
+| <a name="requirement_aws"></a> [aws](#requirement\_aws) | >= 6.28 |
+| <a name="requirement_random"></a> [random](#requirement\_random) | >= 3.7 |
+
+## Providers
+
+No providers.
+
+## Modules
+
+| Name | Source | Version |
+| ---- | ------ | ------- |
+| <a name="module_secret"></a> [secret](#module\_secret) | terraform-aws-modules/secrets-manager/aws | 2.1.0 |
+| <a name="module_this"></a> [this](#module\_this) | git::https://github.com/NHSDigital/screening-terraform-modules-aws.git//infrastructure/modules/tags | v2.5.0 |
+
+## Resources
+
+No resources.
+
+## Inputs
+
+| Name | Description | Type | Default | Required |
+| ---- | ----------- | ---- | ------- | :------: |
+| <a name="input_additional_tag_map"></a> [additional\_tag\_map](#input\_additional\_tag\_map) | Additional key-value pairs to add to each map in `tags_as_list_of_maps`. Not added to `tags` or `id`.<br/>This is for some rare cases where resources want additional configuration of tags<br/>and therefore take a list of maps with tag key, value, and additional configuration. | `map(string)` | `{}` | no |
+| <a name="input_application_role"></a> [application\_role](#input\_application\_role) | The role the application is performing | `string` | `"General"` | no |
+| <a name="input_attributes"></a> [attributes](#input\_attributes) | ID element. Additional attributes (e.g. `workers` or `cluster`) to add to `id`,<br/>in the order they appear in the list. New attributes are appended to the<br/>end of the list. The elements of the list are joined by the `delimiter`<br/>and treated as a single ID element. | `list(string)` | `[]` | no |
+| <a name="input_aws_region"></a> [aws\_region](#input\_aws\_region) | The AWS region | `string` | `"eu-west-2"` | no |
+| <a name="input_context"></a> [context](#input\_context) | Single object for setting entire context at once.<br/>See description of individual variables for details.<br/>Leave string and numeric variables as `null` to use default value.<br/>Individual variable settings (non-null) override settings in context object,<br/>except for attributes, tags, and additional\_tag\_map, which are merged. | `any` | <pre>{<br/>  "additional_tag_map": {},<br/>  "attributes": [],<br/>  "delimiter": null,<br/>  "descriptor_formats": {},<br/>  "enabled": true,<br/>  "environment": null,<br/>  "id_length_limit": null,<br/>  "label_key_case": null,<br/>  "label_order": [],<br/>  "label_value_case": null,<br/>  "labels_as_tags": [<br/>    "unset"<br/>  ],<br/>  "name": null,<br/>  "project": null,<br/>  "regex_replace_chars": null,<br/>  "region": null,<br/>  "service": null,<br/>  "stack": null,<br/>  "tags": {},<br/>  "terraform_source": null,<br/>  "workspace": null<br/>}</pre> | no |
+| <a name="input_create_policy"></a> [create\_policy](#input\_create\_policy) | Whether to attach a resource-based policy to the secret. | `bool` | `false` | no |
+| <a name="input_data_classification"></a> [data\_classification](#input\_data\_classification) | Used to identify the data classification of the resource, e.g 1-5 | `string` | `"n/a"` | no |
+| <a name="input_data_type"></a> [data\_type](#input\_data\_type) | The tag data\_type | `string` | `"None"` | no |
+| <a name="input_delimiter"></a> [delimiter](#input\_delimiter) | Delimiter to be used between ID elements.<br/>Defaults to `-` (hyphen). Set to `""` to use no delimiter at all. | `string` | `null` | no |
+| <a name="input_description"></a> [description](#input\_description) | A description of the secret as viewed in the AWS console. | `string` | `null` | no |
+| <a name="input_descriptor_formats"></a> [descriptor\_formats](#input\_descriptor\_formats) | Describe additional descriptors to be output in the `descriptors` output map.<br/>Map of maps. Keys are names of descriptors. Values are maps of the form<br/>`{<br/>   format = string<br/>   labels = list(string)<br/>}`<br/>(Type is `any` so the map values can later be enhanced to provide additional options.)<br/>`format` is a Terraform format string to be passed to the `format()` function.<br/>`labels` is a list of labels, in order, to pass to `format()` function.<br/>Label values will be normalized before being passed to `format()` so they will be<br/>identical to how they appear in `id`.<br/>Default is `{}` (`descriptors` output will be empty). | `any` | `{}` | no |
+| <a name="input_enable_rotation"></a> [enable\_rotation](#input\_enable\_rotation) | Whether to enable automatic secret rotation via a Lambda function. | `bool` | `false` | no |
+| <a name="input_enabled"></a> [enabled](#input\_enabled) | Set to false to prevent the module from creating any resources | `bool` | `null` | no |
+| <a name="input_environment"></a> [environment](#input\_environment) | ID element. Usually used to indicate role, e.g. 'prd', 'dev', 'test', 'preprod', 'prod', 'uat' | `string` | `null` | no |
+| <a name="input_id_length_limit"></a> [id\_length\_limit](#input\_id\_length\_limit) | Limit `id` to this many characters (minimum 6).<br/>Set to `0` for unlimited length.<br/>Set to `null` for keep the existing setting, which defaults to `0`.<br/>Does not affect `id_full`. | `number` | `null` | no |
+| <a name="input_ignore_secret_changes"></a> [ignore\_secret\_changes](#input\_ignore\_secret\_changes) | When true, Terraform will ignore any changes made to the secret value outside of Terraform (e.g. by a rotation Lambda). Set to true when rotation is enabled. | `bool` | `false` | no |
+| <a name="input_kms_key_id"></a> [kms\_key\_id](#input\_kms\_key\_id) | ARN or ID of the KMS key used to encrypt the secret. Defaults to the AWS-managed key (aws/secretsmanager) when not set. | `string` | `null` | no |
+| <a name="input_label_key_case"></a> [label\_key\_case](#input\_label\_key\_case) | Controls the letter case of the `tags` keys (label names) for tags generated by this module.<br/>Does not affect keys of tags passed in via the `tags` input.<br/>Possible values: `lower`, `title`, `upper`.<br/>Default value: `title`. | `string` | `null` | no |
+| <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_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_on_off_pattern"></a> [on\_off\_pattern](#input\_on\_off\_pattern) | Used to turn resources on and off based on a time pattern | `string` | `"n/a"` | no |
+| <a name="input_owner"></a> [owner](#input\_owner) | The name and or NHS.net email address of the service owner | `string` | `"None"` | no |
+| <a name="input_policy_statements"></a> [policy\_statements](#input\_policy\_statements) | A map of IAM policy statements to attach to the secret policy. Only used when create\_policy is true. | <pre>map(object({<br/>    sid           = optional(string)<br/>    actions       = optional(list(string))<br/>    not_actions   = optional(list(string))<br/>    effect        = optional(string)<br/>    resources     = optional(list(string))<br/>    not_resources = optional(list(string))<br/>    principals = optional(list(object({<br/>      type        = string<br/>      identifiers = list(string)<br/>    })))<br/>    not_principals = optional(list(object({<br/>      type        = string<br/>      identifiers = list(string)<br/>    })))<br/>    condition = optional(list(object({<br/>      test     = string<br/>      values   = list(string)<br/>      variable = string<br/>    })))<br/>  }))</pre> | `{}` | no |
+| <a name="input_project"></a> [project](#input\_project) | ID element. A project identifier, indicating the name or role of the project the resource is for, such as `website` or `api` | `string` | `null` | no |
+| <a name="input_public_facing"></a> [public\_facing](#input\_public\_facing) | Whether this resource is public facing | `bool` | `false` | no |
+| <a name="input_recovery_window_in_days"></a> [recovery\_window\_in\_days](#input\_recovery\_window\_in\_days) | Number of days AWS Secrets Manager waits before permanently deleting the secret. Valid values: 0 (immediate deletion) or 7-30. | `number` | `30` | no |
+| <a name="input_regex_replace_chars"></a> [regex\_replace\_chars](#input\_regex\_replace\_chars) | Terraform regular expression (regex) string.<br/>Characters matching the regex will be removed from the ID elements.<br/>If not set, `"/[^a-zA-Z0-9-]/"` is used to remove all characters other than hyphens, letters and digits. | `string` | `null` | no |
+| <a name="input_region"></a> [region](#input\_region) | ID element \_(Rarely used, not included by default)\_.  Usually an abbreviation of the selected AWS region e.g. 'uw2', 'ew2' or 'gbl' for resources like IAM roles that have no region | `string` | `null` | no |
+| <a name="input_rotation_lambda_arn"></a> [rotation\_lambda\_arn](#input\_rotation\_lambda\_arn) | ARN of the Lambda function that rotates the secret. Required when enable\_rotation is true. | `string` | `""` | no |
+| <a name="input_rotation_rules"></a> [rotation\_rules](#input\_rotation\_rules) | Rotation schedule for the secret. Provide either automatically\_after\_days or a schedule\_expression (cron/rate). Required when enable\_rotation is true. | <pre>object({<br/>    automatically_after_days = optional(number)<br/>    duration                 = optional(string)<br/>    schedule_expression      = optional(string)<br/>  })</pre> | `null` | no |
+| <a name="input_secret_string"></a> [secret\_string](#input\_secret\_string) | The secret value to store as a plaintext string. Use jsonencode() to store structured data such as database credentials. Mutually exclusive with secret\_string\_wo. | `string` | `null` | no |
+| <a name="input_service"></a> [service](#input\_service) | ID element. Usually an abbreviation of your service directorate name, e.g. 'bcss' or 'csms', to help ensure generated IDs are globally unique | `string` | `null` | no |
+| <a name="input_service_category"></a> [service\_category](#input\_service\_category) | The tag service\_category | `string` | `"n/a"` | no |
+| <a name="input_stack"></a> [stack](#input\_stack) | ID element. The name of the stack/component, e.g. `database`, `web`, `waf`, `eks` | `string` | `null` | no |
+| <a name="input_tag_version"></a> [tag\_version](#input\_tag\_version) | Used to identify the tagging version in use | `string` | `"1.0"` | 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_terraform_source"></a> [terraform\_source](#input\_terraform\_source) | Source location to record in the Terraform\_source tag. Defaults to this module path. | `string` | `null` | no |
+| <a name="input_tool"></a> [tool](#input\_tool) | The tool used to deploy the resource | `string` | `"Terraform"` | no |
+| <a name="input_workspace"></a> [workspace](#input\_workspace) | ID element. The Terraform workspace, to help ensure generated IDs are unique across workspaces | `string` | `null` | no |
+
+## Outputs
+
+| Name | Description |
+| ---- | ----------- |
+| <a name="output_secret_arn"></a> [secret\_arn](#output\_secret\_arn) | The ARN of the secret |
+| <a name="output_secret_id"></a> [secret\_id](#output\_secret\_id) | The ID of the secret (same as the ARN) |
+| <a name="output_secret_name"></a> [secret\_name](#output\_secret\_name) | The name of the secret |
+| <a name="output_secret_version_id"></a> [secret\_version\_id](#output\_secret\_version\_id) | The unique identifier of the current version of the secret |
+<!-- END_TF_DOCS -->
+<!-- markdownlint-restore -->
+<!-- vale on -->