Merge pull request #148 from NHSDigital/feature/CCM-14149_Support_Container_Based_Lambdas

CCM-14149: Support Container Based Lambdas

Author: jamesthompson26-nhs

infrastructure/modules/lambda/README.md

@@ -22,14 +22,17 @@
 | <a name="input_filter_pattern"></a> [filter\_pattern](#input\_filter\_pattern) | Filter pattern to use for the log subscription filter | `string` | `""` | no |
 | <a name="input_force_lambda_code_deploy"></a> [force\_lambda\_code\_deploy](#input\_force\_lambda\_code\_deploy) | If the lambda package in s3 has the same commit id tag as the terraform build branch, the lambda will not update automatically. Set to True if making changes to Lambda code from on the same commit for example during development | `bool` | `false` | no |
 | <a name="input_function_code_base_path"></a> [function\_code\_base\_path](#input\_function\_code\_base\_path) | The base path to the sourcecode directories needed for this lambda | `string` | `"./"` | no |
-| <a name="input_function_code_dir"></a> [function\_code\_dir](#input\_function\_code\_dir) | The directory for this lambda | `string` | n/a | yes |
+| <a name="input_function_code_dir"></a> [function\_code\_dir](#input\_function\_code\_dir) | The directory for this lambda | `string` | `null` | no |
 | <a name="input_function_include_common"></a> [function\_include\_common](#input\_function\_include\_common) | Include the 'common' lambda module with this lambda | `bool` | `true` | no |
 | <a name="input_function_module_name"></a> [function\_module\_name](#input\_function\_module\_name) | The name of the function module as used by the lambda handler, e.g. index or exports | `string` | `"index"` | no |
 | <a name="input_function_name"></a> [function\_name](#input\_function\_name) | Base name of this lambda | `string` | n/a | yes |
-| <a name="input_function_s3_bucket"></a> [function\_s3\_bucket](#input\_function\_s3\_bucket) | The bucket to upload Lambda packages to | `string` | n/a | yes |
+| <a name="input_function_s3_bucket"></a> [function\_s3\_bucket](#input\_function\_s3\_bucket) | The bucket to upload Lambda packages to | `string` | `null` | no |
 | <a name="input_group"></a> [group](#input\_group) | The name of the tfscaffold group | `string` | `null` | no |
 | <a name="input_handler_function_name"></a> [handler\_function\_name](#input\_handler\_function\_name) | The name of the lambda handler function (passed directly to the Lambda's handler option) | `string` | `"handler"` | no |
 | <a name="input_iam_policy_document"></a> [iam\_policy\_document](#input\_iam\_policy\_document) | n/a | <pre>object({<br/>    body = string<br/>  })</pre> | `null` | no |
+| <a name="input_image_config"></a> [image\_config](#input\_image\_config) | Optional image configuration for Image-based Lambda | <pre>object({<br/>    entry_point       = optional(list(string))<br/>    command           = optional(list(string))<br/>    working_directory = optional(string)<br/>  })</pre> | `null` | no |
+| <a name="input_image_repository_names"></a> [image\_repository\_names](#input\_image\_repository\_names) | ECR repository names allowed for Image-based Lambda | `list(string)` | `[]` | no |
+| <a name="input_image_uri"></a> [image\_uri](#input\_image\_uri) | ECR image URI for Image-based Lambda | `string` | `null` | no |
 | <a name="input_kms_key_arn"></a> [kms\_key\_arn](#input\_kms\_key\_arn) | KMS key arn to use for this function | `string` | n/a | yes |
 | <a name="input_lambda_at_edge"></a> [lambda\_at\_edge](#input\_lambda\_at\_edge) | Whether this Lambda is a Lambda@Edge function | `bool` | `false` | no |
 | <a name="input_lambda_dlq_message_retention_seconds"></a> [lambda\_dlq\_message\_retention\_seconds](#input\_lambda\_dlq\_message\_retention\_seconds) | The number of seconds to retain messages in the Lambda DLQ SQS queue | `number` | `1209600` | no |
@@ -41,10 +44,11 @@
 | <a name="input_log_subscription_lambda_create_permission"></a> [log\_subscription\_lambda\_create\_permission](#input\_log\_subscription\_lambda\_create\_permission) | Whether to create a permission for the log forwarder. Set to false if using a generic one. | `bool` | `true` | no |
 | <a name="input_log_subscription_role_arn"></a> [log\_subscription\_role\_arn](#input\_log\_subscription\_role\_arn) | The ARN of the IAM role to use for the log subscription filter | `string` | `""` | no |
 | <a name="input_memory"></a> [memory](#input\_memory) | The amount of memory to apply to the created Lambda | `number` | n/a | yes |
+| <a name="input_package_type"></a> [package\_type](#input\_package\_type) | Lambda package type: Zip or Image | `string` | `"Zip"` | no |
 | <a name="input_permission_statements"></a> [permission\_statements](#input\_permission\_statements) | Statements giving an external source permission to invoke the Lambda function | <pre>list(object({<br/>    action         = optional(string)<br/>    principal      = string<br/>    source_arn     = optional(string)<br/>    source_account = optional(string)<br/>    statement_id   = string<br/>  }))</pre> | `[]` | no |
 | <a name="input_project"></a> [project](#input\_project) | The name of the tfscaffold project | `string` | n/a | yes |
 | <a name="input_region"></a> [region](#input\_region) | The AWS Region | `string` | n/a | yes |
-| <a name="input_runtime"></a> [runtime](#input\_runtime) | The runtime to use for the lambda function | `string` | n/a | yes |
+| <a name="input_runtime"></a> [runtime](#input\_runtime) | The runtime to use for the lambda function | `string` | `null` | no |
 | <a name="input_schedule"></a> [schedule](#input\_schedule) | The fully qualified Cloudwatch Events schedule for when to run the lambda function, e.g. rate(1 day) or a cron() expression. Default disables all events resources | `string` | `""` | no |
 | <a name="input_send_to_firehose"></a> [send\_to\_firehose](#input\_send\_to\_firehose) | Enable sending logs to firehose | `bool` | `true` | no |
 | <a name="input_sns_destination"></a> [sns\_destination](#input\_sns\_destination) | SNS Topic ARN to be used for on-failure Lambda invocation records | `string` | `null` | no |

infrastructure/modules/lambda/data_archive_file_lambda.tf

@@ -1,4 +1,5 @@
 data "archive_file" "lambda" {
+  count = local.package_type == "zip" ? 1 : 0
   type       = "zip"
   source_dir = "${path.root}/${var.function_code_base_path}/${var.function_code_dir}"
 

infrastructure/modules/lambda/data_iam_policy_document_ecr.tf

@@ -0,0 +1,26 @@
+data "aws_iam_policy_document" "ecr" {
+  statement {
+    effect = "Allow"
+
+    actions = [
+      "ecr:GetAuthorizationToken",
+    ]
+
+    resources = ["*"]
+  }
+
+  statement {
+    effect = "Allow"
+
+    actions = [
+      "ecr:BatchGetImage",
+      "ecr:GetDownloadUrlForLayer",
+      "ecr:BatchCheckLayerAvailability",
+    ]
+
+    resources = [
+      for repo_name in var.image_repository_names :
+      "arn:aws:ecr:${var.region}:${var.aws_account_id}:repository/${repo_name}"
+    ]
+  }
+}

infrastructure/modules/lambda/iam_role_policy_ecr.tf

@@ -0,0 +1,6 @@
+resource "aws_iam_role_policy" "ecr" {
+  count  = local.package_type == "image" ? 1 : 0
+  name   = "${local.csi}-ecr"
+  role   = aws_iam_role.main.id
+  policy = data.aws_iam_policy_document.ecr.json
+}

infrastructure/modules/lambda/lambda_function.tf

@@ -2,15 +2,27 @@ resource "aws_lambda_function" "main" {
   description   = var.description
   function_name = local.csi
   role          = aws_iam_role.main.arn
-  handler       = "${var.function_module_name}.${var.handler_function_name}"
-  runtime       = var.runtime
+  handler       = local.package_type == "zip" ? "${var.function_module_name}.${var.handler_function_name}" : null
+  runtime       = local.package_type == "zip" ? var.runtime : null
+  package_type  = title(local.package_type)
   publish       = true
   memory_size   = var.memory
   timeout       = var.timeout
 
-  s3_bucket         = aws_s3_object.lambda.bucket
-  s3_key            = aws_s3_object.lambda.key
-  s3_object_version = aws_s3_object.lambda.version_id
+  s3_bucket         = local.package_type == "zip" ? aws_s3_object.lambda[0].bucket : null
+  s3_key            = local.package_type == "zip" ? aws_s3_object.lambda[0].key : null
+  s3_object_version = local.package_type == "zip" ? aws_s3_object.lambda[0].version_id : null
+
+  image_uri = local.package_type == "image" ? var.image_uri : null
+
+  dynamic "image_config" {
+    for_each = local.package_type == "image" && var.image_config != null ? [1] : []
+    content {
+      entry_point       = try(var.image_config.entry_point, null)
+      command           = try(var.image_config.command, null)
+      working_directory = try(var.image_config.working_directory, null)
+    }
+  }
 
   logging_config {
     application_log_level = var.application_log_level
@@ -19,12 +31,12 @@ resource "aws_lambda_function" "main" {
     system_log_level      = var.system_log_level
   }
 
-  layers = compact(concat(
+  layers = local.package_type == "zip" ? compact(concat(
     var.layers,
     [
       var.enable_lambda_insights && var.lambda_at_edge == false ? "arn:aws:lambda:${var.region}:580247275435:layer:LambdaInsightsExtension:53" : null
     ]
-  ))
+  )) : []
 
   environment {
     variables = var.lambda_env_vars

infrastructure/modules/lambda/locals.tf

@@ -1,6 +1,8 @@
 locals {
   module = "lambda"
 
+  package_type = lower(var.package_type)
+
   # Compound Scope Identifier
   csi = replace(
     format(

infrastructure/modules/lambda/s3_object_lambda.tf

@@ -1,12 +1,13 @@
 resource "aws_s3_object" "lambda" {
+  count  = local.package_type == "zip" ? 1 : 0
   bucket = var.function_s3_bucket
   key    = "${local.csi}.zip"
-  source = data.archive_file.lambda.output_path
+  source = data.archive_file.lambda[0].output_path
 
-  source_hash = var.force_lambda_code_deploy ? data.archive_file.lambda.output_base64sha256 : null
+  source_hash = var.force_lambda_code_deploy ? data.archive_file.lambda[0].output_base64sha256 : null
 
   metadata = {
-    hash     = data.archive_file.lambda.output_base64sha256
+    hash     = data.archive_file.lambda[0].output_base64sha256
     function = local.csi
     commit   = try(data.external.git_commit.result["sha"], "null")
   }

infrastructure/modules/lambda/variables.tf

@@ -92,6 +92,55 @@ variable "log_retention_in_days" {
 variable "runtime" {
   type        = string
   description = "The runtime to use for the lambda function"
+  default     = null
+
+  validation {
+    condition     = lower(var.package_type) != "zip" || (var.runtime != null && var.runtime != "")
+    error_message = "runtime must be set when package_type is Zip."
+  }
+}
+
+variable "package_type" {
+  type        = string
+  description = "Lambda package type: Zip or Image"
+  default     = "Zip"
+
+  validation {
+    condition     = contains(["zip", "image"], lower(var.package_type))
+    error_message = "package_type must be either Zip or Image."
+  }
+}
+
+variable "image_uri" {
+  type        = string
+  description = "ECR image URI for Image-based Lambda"
+  default     = null
+
+  validation {
+    condition     = lower(var.package_type) != "image" || (var.image_uri != null && var.image_uri != "")
+    error_message = "image_uri must be set when package_type is Image."
+  }
+}
+
+variable "image_config" {
+  type = object({
+    entry_point       = optional(list(string))
+    command           = optional(list(string))
+    working_directory = optional(string)
+  })
+  description = "Optional image configuration for Image-based Lambda"
+  default     = null
+}
+
+variable "image_repository_names" {
+  type        = list(string)
+  description = "ECR repository names allowed for Image-based Lambda"
+  default     = []
+
+  validation {
+    condition     = lower(var.package_type) != "image" || length(var.image_repository_names) > 0
+    error_message = "image_repository_names must include at least one repository name when package_type is Image."
+  }
 }
 
 variable "schedule" {
@@ -122,11 +171,23 @@ variable "function_code_base_path" {
 variable "function_code_dir" {
   type        = string
   description = "The directory for this lambda"
+  default     = null
+
+  validation {
+    condition     = lower(var.package_type) != "zip" || (var.function_code_dir != null && var.function_code_dir != "")
+    error_message = "function_code_dir must be set when package_type is Zip."
+  }
 }
 
 variable "function_s3_bucket" {
   type        = string
   description = "The bucket to upload Lambda packages to"
+  default     = null
+
+  validation {
+    condition     = lower(var.package_type) != "zip" || (var.function_s3_bucket != null && var.function_s3_bucket != "")
+    error_message = "function_s3_bucket must be set when package_type is Zip."
+  }
 }
 
 variable "function_include_common" {