feat: root module to provision optional ecs cluster and an ecs service, and add basic tests

Author: saumitra-dev

main.tf

@@ -0,0 +1,36 @@
+################################################################################
+# ECS Cluster
+################################################################################
+
+module "ecs_cluster" {
+  source  = "terraform-aws-modules/ecs/aws//modules/cluster"
+  version = "~> 5.11.3"
+
+  count = var.create_cluster ? 1 : 0
+
+  cluster_name                          = var.cluster_name
+  default_capacity_provider_use_fargate = false
+
+  tags = var.cluster_tags
+}
+
+################################################################################
+# ECS Service
+################################################################################
+
+module "ecs_service" {
+  source  = "terraform-aws-modules/ecs/aws//modules/service"
+  version = "~> 5.11.3"
+
+  name        = var.service_name
+  cluster_arn = var.create_cluster ? module.ecs_cluster[0].arn : var.cluster_arn
+  subnet_ids  = var.service_subnet_ids
+
+  cpu    = var.service_cpu
+  memory = var.service_memory
+
+  launch_type              = "EC2"
+  requires_compatibilities = ["EC2"]
+
+  tags = var.service_tags
+}

outputs.tf

@@ -0,0 +1,17 @@
+##############################
+# ECS Cluster Outputs
+##############################
+
+output "cluster_arn" {
+  description = "ARN of the ECS Cluster"
+  value       = var.create_cluster ? module.ecs_cluster[0].arn : var.cluster_arn
+}
+
+##############################
+# ECS Service Outputs
+##############################
+
+output "service_id" {
+  description = "Identifier of the ECS Service"
+  value       = module.ecs_service.id
+}

tests/unit_tests.tftest.hcl

@@ -0,0 +1,99 @@
+###########################################################
+# ECS Cluster Tests
+###########################################################
+
+run "do_not_create_cluster_when_false" {
+  command = plan
+
+  module {
+    source = "./"
+  }
+
+  variables {
+    create_cluster = false
+
+    service_name       = "test-service"
+    cluster_arn        = "arn:aws:ecs:ap-south-1:471112575944:cluster/default"
+    service_subnet_ids = ["subnet-0ba38303b254c0785"]
+    service_cpu        = 128
+    service_memory     = 256
+  }
+
+  assert {
+    condition     = length(module.ecs_cluster) == 0
+    error_message = "ECS cluster was created even after setting `create_cluster` to `false`"
+  }
+}
+
+run "create_cluster_when_true" {
+  command = plan
+
+  module {
+    source = "./"
+  }
+
+  variables {
+    create_cluster = true
+    cluster_name   = "test-cluster"
+
+    service_name       = "test-service"
+    service_subnet_ids = ["subnet-0ba38303b254c0785"]
+    service_cpu        = 128
+    service_memory     = 256
+  }
+
+  assert {
+    condition     = length(module.ecs_cluster) == 1
+    error_message = "ECS cluster was not created even after setting `create_cluster` to `true`"
+  }
+}
+
+run "cluster_name_match" {
+  command = plan
+
+  module {
+    source = "./"
+  }
+
+  variables {
+    create_cluster = true
+    cluster_name   = "test-cluster"
+
+    service_name       = "test-service"
+    service_subnet_ids = ["subnet-0ba38303b254c0785"]
+    service_cpu        = 128
+    service_memory     = 256
+  }
+
+  assert {
+    condition     = module.ecs_cluster[0].name == var.cluster_name
+    error_message = "ECS Cluster name mismatch after creation"
+  }
+}
+
+###########################################################
+# ECS Service Tests
+###########################################################
+
+run "service_name_match" {
+  command = plan
+
+  module {
+    source = "./"
+  }
+
+  variables {
+    create_cluster = true
+    cluster_name   = "test-cluster"
+
+    service_name       = "test-service"
+    service_subnet_ids = ["subnet-0ba38303b254c0785"]
+    service_cpu        = 128
+    service_memory     = 256
+  }
+
+  assert {
+    condition     = module.ecs_service.name == var.service_name
+    error_message = "ECS Cluster name mismatch after creation"
+  }
+}

variables.tf

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+#######################
+# ECS Cluster Variables
+#######################
+
+variable "create_cluster" {
+  description = "Creates an ECS cluster"
+  type        = bool
+  default     = true
+}
+
+variable "cluster_name" {
+  description = "Name of the ECS Cluster to create"
+  type        = string
+  default     = ""
+}
+
+variable "cluster_tags" {
+  description = "Resource Tags for ECS Cluster"
+  type        = map(any)
+  default     = {}
+}
+
+#######################
+# ECS Service Variables
+#######################
+
+variable "service_name" {
+  description = "Name of the ECS Service"
+  type        = string
+}
+
+variable "cluster_arn" {
+  description = "ARN of the ECS cluster under which the service will be created"
+  type        = string
+  default     = null
+
+  validation {
+    condition     = var.create_cluster == true || startswith(var.cluster_arn != null ? var.cluster_arn : "", "arn:")
+    error_message = "Specified Cluster ARN must be a valid ARN starting with \"arn:\"."
+  }
+}
+
+variable "service_subnet_ids" {
+  description = "VPC subnet ids where the ECS services will be deployed"
+  type        = list(string)
+
+  validation {
+    condition     = length(var.service_subnet_ids) > 0
+    error_message = "Specified subnet ids must contain at least one valid subnet identifier."
+  }
+
+  validation {
+    condition     = alltrue([for subnet_id in var.service_subnet_ids : startswith(subnet_id, "subnet-")])
+    error_message = "Specified subnet ids must be valid subnet identifiers starting with \"subnet-\"."
+  }
+}
+
+variable "service_cpu" {
+  description = "CPU allocation for ECS task definitions"
+  type        = number
+
+  validation {
+    condition     = var.service_cpu > 0
+    error_message = "Specified CPU allocation must be a positive number."
+  }
+}
+
+variable "service_memory" {
+  description = "Memory allocation for ECS task definitions"
+  type        = number
+
+  validation {
+    condition     = var.service_memory > 0
+    error_message = "Specified Memory allocation must be a positive number."
+  }
+}
+
+variable "service_tags" {
+  description = "Resource Tags for ECS Service"
+  type        = map(any)
+  default     = {}
+}

versions.tf

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+terraform {
+  required_version = ">= 1.4.6"
+}