Parameterize Terraform Child Module

terraform/main.tf

@@ -19,6 +19,22 @@ provider "aws" {
 
 data "aws_caller_identity" "current" {}
 
+data "aws_efs_file_system" "input" {
+  creation_token = "${var.prefix}-input"
+}
+
+data "aws_efs_file_system" "flpe" {
+  creation_token = "${var.prefix}-flpe"
+}
+
+data "aws_iam_role" "job" {
+  name = "${var.prefix}-batch-job-role"
+}
+
+data "aws_iam_role" "execution" {
+  name = "${var.prefix}-ecs-exe-task-role"
+}
+
 locals {
   account_id = sensitive(data.aws_caller_identity.current.account_id)
   default_tags = length(var.default_tags) == 0 ? {
@@ -29,10 +45,16 @@ locals {
 }
 
 module "confluence-metroman" {
-  source      = "./modules/metroman"
-  app_name    = var.app_name
-  app_version = var.app_version
-  aws_region  = var.aws_region
-  environment = var.environment
-  prefix      = var.prefix
-}
+  source                 = "./modules/metroman"
+  app_name               = var.app_name
+  app_version            = var.app_version
+  aws_region             = var.aws_region
+  efs_file_system_ids    = {
+    input = data.aws_efs_file_system.input.file_system_id
+    flpe  = data.aws_efs_file_system.flpe.file_system_id
+  }
+  environment            = var.environment
+  iam_execution_role_arn = data.aws_iam_role.execution.arn
+  iam_job_role_arn       = data.aws_iam_role.job.arn
+  prefix                 = var.prefix
+}

terraform/modules/metroman/confluence-metroman.tf

@@ -1,54 +1,57 @@
 # Job Definition
 resource "aws_batch_job_definition" "generate_batch_jd_metroman" {
-  name                  = "${var.prefix}-metroman"
-  type                  = "container"
-  container_properties  = <<CONTAINER_PROPERTIES
-  {
-    "image": "${local.account_id}.dkr.ecr.us-west-2.amazonaws.com/${var.prefix}-metroman",
-    "executionRoleArn": "${data.aws_iam_role.exe_role.arn}",
-    "jobRoleArn": "${data.aws_iam_role.job_role.arn}",
-    "fargatePlatformConfiguration": { "platformVersion": "LATEST" },
-    "logConfiguration": {
-      "logDriver" : "awslogs",
-      "options": {
-        "awslogs-group" : "${data.aws_cloudwatch_log_group.cw_log_group.name}"
+  name = "${var.prefix}-metroman"
+  type = "container"
+  platform_capabilities = ["FARGATE"]
+  propagate_tags = true
+  tags = { "job_definition": "${var.prefix}-metroman" }
+
+  container_properties  = jsonencode({
+    image = "${local.account_id}.dkr.ecr.us-west-2.amazonaws.com/${var.prefix}-metroman:${var.image_tag}"
+    executionRoleArn = var.iam_execution_role_arn
+    jobRoleArn = var.iam_job_role_arn
+    fargatePlatformConfiguration = {
+      platformVersion = "LATEST"
+    }
+    logConfiguration = {
+      logDriver = "awslogs"
+      options = {
+        awslogs-group = aws_cloudwatch_log_group.cw_log_group.name
       }
-    },
-    "resourceRequirements": [
-      {"type": "MEMORY", "value": "8192"},
-      {"type": "VCPU", "value": "4"}
-    ],
-    "mountPoints": [
-      {
-        "sourceVolume": "input",
-        "containerPath": "/mnt/data/input",
-        "readOnly": true
-      },
-      {
-        "sourceVolume": "flpe",
-        "containerPath": "/mnt/data/output",
-        "readOnly": false
+    }
+    resourceRequirements = [{
+      type = "MEMORY"
+      value = "8192"
+    }, {
+      type = "VCPU",
+      value = "4"
+    }]
+    mountPoints = [{
+      sourceVolume = "input",
+      containerPath = "/mnt/data/input"
+      readOnly = false
+    }, {
+      sourceVolume = "flpe"
+      containerPath = "/mnt/data/output"
+      readOnly = false
+    }]
+    volumes = [{
+      name = "input"
+      efsVolumeConfiguration = {
+        fileSystemId = var.efs_file_system_ids["input"]
+        rootDirectory = "/"
       }
-    ],
-    "volumes": [
-      {
-        "name": "input",
-        "efsVolumeConfiguration": {
-          "fileSystemId": "${data.aws_efs_file_system.aws_efs_input.file_system_id}",
-          "rootDirectory": "/"
-        }
-      },
-      {
-        "name": "flpe",
-        "efsVolumeConfiguration": {
-          "fileSystemId": "${data.aws_efs_file_system.aws_efs_flpe.file_system_id}",
-          "rootDirectory": "/metroman"
-        }
+    }, {
+      name = "flpe"
+      efsVolumeConfiguration = {
+        fileSystemId = var.efs_file_system_ids["flpe"]
+        rootDirectory = "/metroman"
       }
-    ]
-  }
-  CONTAINER_PROPERTIES
-  platform_capabilities = ["FARGATE"]
-  propagate_tags        = true
-  tags = { "job_definition": "${var.prefix}-metroman" }
+    }]
+  })
+}
+
+# Log group
+resource "aws_cloudwatch_log_group" "cw_log_group" {
+  name = "/aws/batch/job/${var.prefix}-metroman/"
 }

terraform/modules/metroman/main.tf

@@ -1,32 +1,7 @@
 # Data sources
 data "aws_caller_identity" "current" {}
 
-data "aws_cloudwatch_log_group" "cw_log_group" {
-  name = "/aws/batch/job/${var.prefix}-metroman/"
-}
-
-data "aws_efs_file_system" "aws_efs_input" {
-  creation_token = "${var.prefix}-input"
-}
-
-data "aws_efs_file_system" "aws_efs_flpe" {
-  creation_token = "${var.prefix}-flpe"
-}
-
-data "aws_iam_role" "job_role" {
-  name = "${var.prefix}-batch-job-role"
-}
-
-data "aws_iam_role" "exe_role" {
-  name = "${var.prefix}-ecs-exe-task-role"
-}
-
 # Local variables
 locals {
   account_id = data.aws_caller_identity.current.account_id
-  default_tags = length(var.default_tags) == 0 ? {
-    application : var.app_name,
-    environment : lower(var.environment),
-    version : var.app_version
-  } : var.default_tags
-}
+}

terraform/modules/metroman/variables.tf

@@ -16,15 +16,36 @@ variable "aws_region" {
 }
 
 variable "default_tags" {
-  type    = map(string)
-  default = {}
+  type        = map(string)
+  default     = {}
+}
+
+variable "efs_file_system_ids" {
+  type        = map(string)
+  description = "Map of EFS file system ids to pass to the container definition"
 }
 
 variable "environment" {
   type        = string
   description = "The environment in which to deploy to"
 }
 
+variable "iam_execution_role_arn" {
+  type        = string
+  description = "The IAM ARN of the execution role"
+}
+
+variable "iam_job_role_arn" {
+  type        = string
+  description = "The IAM ARN of the job role"
+}
+
+variable "image_tag" {
+  type        = string
+  description = "The container image tag to utilize"
+  default     = "latest"
+}
+
 variable "prefix" {
   type        = string
   description = "Prefix to add to all AWS resources as a unique identifier"

terraform/variables.tf

@@ -16,8 +16,8 @@ variable "aws_region" {
 }
 
 variable "default_tags" {
-  type    = map(string)
-  default = {}
+  type        = map(string)
+  default     = {}
 }
 
 variable "environment" {