Add support for declaring simple lambda permissions in-module

README.md

@@ -130,6 +130,7 @@ Available targets:
 | [aws_iam_role_policy_attachment.vpc_access](https://registry.terraform.io/providers/hashicorp/aws/latest/docs/resources/iam_role_policy_attachment) | resource |
 | [aws_iam_role_policy_attachment.xray](https://registry.terraform.io/providers/hashicorp/aws/latest/docs/resources/iam_role_policy_attachment) | resource |
 | [aws_lambda_function.this](https://registry.terraform.io/providers/hashicorp/aws/latest/docs/resources/lambda_function) | resource |
+| [aws_lambda_permission.invoke_function](https://registry.terraform.io/providers/hashicorp/aws/latest/docs/resources/lambda_permission) | resource |
 | [aws_caller_identity.this](https://registry.terraform.io/providers/hashicorp/aws/latest/docs/data-sources/caller_identity) | data source |
 | [aws_iam_policy_document.assume_role_policy](https://registry.terraform.io/providers/hashicorp/aws/latest/docs/data-sources/iam_policy_document) | data source |
 | [aws_iam_policy_document.ssm](https://registry.terraform.io/providers/hashicorp/aws/latest/docs/data-sources/iam_policy_document) | data source |
@@ -163,6 +164,7 @@ Available targets:
 | <a name="input_image_config"></a> [image\_config](#input\_image\_config) | The Lambda OCI [image configurations](https://registry.terraform.io/providers/hashicorp/aws/latest/docs/resources/lambda_function#image_config)<br>  block with three (optional) arguments:<br>  - *entry\_point* - The ENTRYPOINT for the docker image (type `list(string)`).<br>  - *command* - The CMD for the docker image (type `list(string)`).<br>  - *working\_directory* - The working directory for the docker image (type `string`). | `any` | `{}` | no |
 | <a name="input_image_uri"></a> [image\_uri](#input\_image\_uri) | The ECR image URI containing the function's deployment package. Conflicts with filename, s3\_bucket, s3\_key, and s3\_object\_version. | `string` | `null` | no |
 | <a name="input_inline_iam_policy"></a> [inline\_iam\_policy](#input\_inline\_iam\_policy) | Inline policy document (JSON) to attach to the lambda role | `string` | `null` | no |
+| <a name="input_invoke_function_permissions"></a> [invoke\_function\_permissions](#input\_invoke\_function\_permissions) | Defines which external source(s) can invoke this function (action 'lambda:InvokeFunction'). Attributes map to those of https://registry.terraform.io/providers/hashicorp/aws/latest/docs/resources/lambda_permission. NOTE: to keep things simple, we only expose a subset of said attributes. If a more complex configuration is needed, declare the necessary lambda permissions outside of this module | <pre>list(object({<br>    principal  = string<br>    source_arn = string<br>  }))</pre> | `[]` | no |
 | <a name="input_kms_key_arn"></a> [kms\_key\_arn](#input\_kms\_key\_arn) | Amazon Resource Name (ARN) of the AWS Key Management Service (KMS) key that is used to encrypt environment variables.<br>  If this configuration is not provided when environment variables are in use, AWS Lambda uses a default service key.<br>  If this configuration is provided when environment variables are not in use, the AWS Lambda API does not save this<br>  configuration and Terraform will show a perpetual difference of adding the key. To fix the perpetual difference,<br>  remove this configuration. | `string` | `""` | 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 |

docs/terraform.md

@@ -25,13 +25,15 @@
 |------|------|
 | [aws_iam_policy.ssm](https://registry.terraform.io/providers/hashicorp/aws/latest/docs/resources/iam_policy) | resource |
 | [aws_iam_role.this](https://registry.terraform.io/providers/hashicorp/aws/latest/docs/resources/iam_role) | resource |
+| [aws_iam_role_policy.inline](https://registry.terraform.io/providers/hashicorp/aws/latest/docs/resources/iam_role_policy) | resource |
 | [aws_iam_role_policy_attachment.cloudwatch_insights](https://registry.terraform.io/providers/hashicorp/aws/latest/docs/resources/iam_role_policy_attachment) | resource |
 | [aws_iam_role_policy_attachment.cloudwatch_logs](https://registry.terraform.io/providers/hashicorp/aws/latest/docs/resources/iam_role_policy_attachment) | resource |
 | [aws_iam_role_policy_attachment.custom](https://registry.terraform.io/providers/hashicorp/aws/latest/docs/resources/iam_role_policy_attachment) | resource |
 | [aws_iam_role_policy_attachment.ssm](https://registry.terraform.io/providers/hashicorp/aws/latest/docs/resources/iam_role_policy_attachment) | resource |
 | [aws_iam_role_policy_attachment.vpc_access](https://registry.terraform.io/providers/hashicorp/aws/latest/docs/resources/iam_role_policy_attachment) | resource |
 | [aws_iam_role_policy_attachment.xray](https://registry.terraform.io/providers/hashicorp/aws/latest/docs/resources/iam_role_policy_attachment) | resource |
 | [aws_lambda_function.this](https://registry.terraform.io/providers/hashicorp/aws/latest/docs/resources/lambda_function) | resource |
+| [aws_lambda_permission.invoke_function](https://registry.terraform.io/providers/hashicorp/aws/latest/docs/resources/lambda_permission) | resource |
 | [aws_caller_identity.this](https://registry.terraform.io/providers/hashicorp/aws/latest/docs/data-sources/caller_identity) | data source |
 | [aws_iam_policy_document.assume_role_policy](https://registry.terraform.io/providers/hashicorp/aws/latest/docs/data-sources/iam_policy_document) | data source |
 | [aws_iam_policy_document.ssm](https://registry.terraform.io/providers/hashicorp/aws/latest/docs/data-sources/iam_policy_document) | data source |
@@ -64,6 +66,8 @@
 | <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_image_config"></a> [image\_config](#input\_image\_config) | The Lambda OCI [image configurations](https://registry.terraform.io/providers/hashicorp/aws/latest/docs/resources/lambda_function#image_config)<br>  block with three (optional) arguments:<br>  - *entry\_point* - The ENTRYPOINT for the docker image (type `list(string)`).<br>  - *command* - The CMD for the docker image (type `list(string)`).<br>  - *working\_directory* - The working directory for the docker image (type `string`). | `any` | `{}` | no |
 | <a name="input_image_uri"></a> [image\_uri](#input\_image\_uri) | The ECR image URI containing the function's deployment package. Conflicts with filename, s3\_bucket, s3\_key, and s3\_object\_version. | `string` | `null` | no |
+| <a name="input_inline_iam_policy"></a> [inline\_iam\_policy](#input\_inline\_iam\_policy) | Inline policy document (JSON) to attach to the lambda role | `string` | `null` | no |
+| <a name="input_invoke_function_permissions"></a> [invoke\_function\_permissions](#input\_invoke\_function\_permissions) | Defines which external source(s) can invoke this function (action 'lambda:InvokeFunction'). Attributes map to those of https://registry.terraform.io/providers/hashicorp/aws/latest/docs/resources/lambda_permission. NOTE: to keep things simple, we only expose a subset of said attributes. If a more complex configuration is needed, declare the necessary lambda permissions outside of this module | <pre>list(object({<br>    principal  = string<br>    source_arn = string<br>  }))</pre> | `[]` | no |
 | <a name="input_kms_key_arn"></a> [kms\_key\_arn](#input\_kms\_key\_arn) | Amazon Resource Name (ARN) of the AWS Key Management Service (KMS) key that is used to encrypt environment variables.<br>  If this configuration is not provided when environment variables are in use, AWS Lambda uses a default service key.<br>  If this configuration is provided when environment variables are not in use, the AWS Lambda API does not save this<br>  configuration and Terraform will show a perpetual difference of adding the key. To fix the perpetual difference,<br>  remove this configuration. | `string` | `""` | 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 |

examples/complete/main.tf

@@ -103,7 +103,32 @@ module "lambda" {
     }
   JSON
 
+  invoke_function_permissions = [
+    {
+      principal  = "s3.amazonaws.com"
+      source_arn = join("", aws_s3_bucket.example[*].arn)
+    }
+  ]
+
   context = module.this.context
 
   depends_on = [aws_iam_policy.inside]
 }
+
+resource "aws_s3_bucket" "example" {
+  count = local.enabled ? 1 : 0
+}
+
+resource "aws_s3_bucket_notification" "example" {
+  count = local.enabled ? 1 : 0
+
+  bucket = aws_s3_bucket.example[0].id
+  lambda_function {
+    lambda_function_arn = module.lambda.arn
+    events              = ["s3:ObjectCreated:*"]
+  }
+  # Lambda permissions must be created prior to setting up the notification
+  depends_on = [
+    module.lambda
+  ]
+}

lambda-permissions.tf

@@ -0,0 +1,8 @@
+resource "aws_lambda_permission" "invoke_function" {
+  for_each = local.enabled ? { for i, permission in var.invoke_function_permissions : i => permission } : {}
+
+  action        = "lambda:InvokeFunction"
+  function_name = aws_lambda_function.this[0].function_name
+  principal     = each.value.principal
+  source_arn    = each.value.source_arn
+}

variables.tf

@@ -245,3 +245,12 @@ variable "inline_iam_policy" {
   description = "Inline policy document (JSON) to attach to the lambda role"
   default     = null
 }
+
+variable "invoke_function_permissions" {
+  type = list(object({
+    principal  = string
+    source_arn = string
+  }))
+  description = "Defines which external source(s) can invoke this function (action 'lambda:InvokeFunction'). Attributes map to those of https://registry.terraform.io/providers/hashicorp/aws/latest/docs/resources/lambda_permission. NOTE: to keep things simple, we only expose a subset of said attributes. If a more complex configuration is needed, declare the necessary lambda permissions outside of this module"
+  default     = []
+}