feat: Remove empty containers (map/list) from container definition (#336)

fix: Remove empty containers (map/list) from container definition

Author: bryantbiggs

examples/container-definition/README.md

@@ -36,12 +36,14 @@ Note that this example may create resources which will incur monetary charges on
 | Name | Source | Version |
 |------|--------|---------|
 | <a name="module_ecs_container_definition"></a> [ecs\_container\_definition](#module\_ecs\_container\_definition) | ../../modules/container-definition | n/a |
+| <a name="module_ecs_container_definition_simple"></a> [ecs\_container\_definition\_simple](#module\_ecs\_container\_definition\_simple) | ../../modules/container-definition | n/a |
 
 ## Resources
 
 | Name | Type |
 |------|------|
 | [null_resource.container_definition_json](https://registry.terraform.io/providers/hashicorp/null/latest/docs/resources/resource) | resource |
+| [null_resource.container_definition_json_simple](https://registry.terraform.io/providers/hashicorp/null/latest/docs/resources/resource) | resource |
 
 ## Inputs
 
@@ -57,6 +59,8 @@ Note that this example may create resources which will incur monetary charges on
 | <a name="output_cloudwatch_log_group_name"></a> [cloudwatch\_log\_group\_name](#output\_cloudwatch\_log\_group\_name) | Name of CloudWatch log group created |
 | <a name="output_container_definition"></a> [container\_definition](#output\_container\_definition) | Container definition |
 | <a name="output_container_definition_json"></a> [container\_definition\_json](#output\_container\_definition\_json) | Container definition |
+| <a name="output_container_definition_json_simple"></a> [container\_definition\_json\_simple](#output\_container\_definition\_json\_simple) | Container definition |
+| <a name="output_container_definition_simple"></a> [container\_definition\_simple](#output\_container\_definition\_simple) | Container definition |
 <!-- END_TF_DOCS -->
 
 ## License

examples/container-definition/definition_simple.json

@@ -0,0 +1,32 @@
+{
+  "cpu": 256,
+  "essential": true,
+  "image": "public.ecr.aws/aws-containers/ecsdemo-frontend:776fd50",
+  "interactive": false,
+  "linuxParameters": {
+    "initProcessEnabled": false
+  },
+  "logConfiguration": {
+    "logDriver": "awslogs",
+    "options": {
+      "awslogs-group": "/aws/ecs",
+      "awslogs-region": "eu-west-1",
+      "awslogs-stream-prefix": "ecs"
+    }
+  },
+  "memory": 512,
+  "portMappings": [
+    {
+      "containerPort": 80,
+      "hostPort": 80,
+      "name": "app",
+      "protocol": "tcp"
+    }
+  ],
+  "privileged": false,
+  "pseudoTerminal": false,
+  "readonlyRootFilesystem": false,
+  "startTimeout": 30,
+  "stopTimeout": 120,
+  "versionConsistency": "disabled"
+}

examples/container-definition/main.tf

@@ -155,3 +155,24 @@ module "ecs_container_definition" {
 
   tags = local.tags
 }
+
+module "ecs_container_definition_simple" {
+  source = "../../modules/container-definition"
+
+  image                  = "public.ecr.aws/aws-containers/ecsdemo-frontend:776fd50"
+  cpu                    = 256
+  memory                 = 512
+  essential              = true
+  readonlyRootFilesystem = false
+  portMappings = [{
+    name          = "app"
+    protocol      = "tcp"
+    containerPort = 80
+    hostPort      = 80
+  }]
+  restartPolicy = {
+    enabled = false
+  }
+
+  tags = local.tags
+}

examples/container-definition/outputs.tf

@@ -25,6 +25,29 @@ resource "null_resource" "container_definition_json" {
   }
 }
 
+output "container_definition_simple" {
+  description = "Container definition"
+  value       = module.ecs_container_definition.container_definition
+}
+
+output "container_definition_json_simple" {
+  description = "Container definition"
+  value       = module.ecs_container_definition.container_definition_json
+}
+
+resource "null_resource" "container_definition_json_simple" {
+  count = var.write_container_definition_to_file ? 1 : 0
+
+  triggers = {
+    container_definition_json = timestamp()
+  }
+
+  provisioner "local-exec" {
+    # Need the output pretty-printed and sorted for comparison
+    command = "echo '${module.ecs_container_definition_simple.container_definition_json}' | jq -S > ./definition_simple.json"
+  }
+}
+
 ################################################################################
 # CloudWatch Log Group
 ################################################################################

modules/container-definition/README.md

@@ -155,9 +155,9 @@ No modules.
 | <a name="input_dockerSecurityOptions"></a> [dockerSecurityOptions](#input\_dockerSecurityOptions) | A list of strings to provide custom labels for SELinux and AppArmor multi-level security systems. This field isn't valid for containers in tasks using the Fargate launch type | `list(string)` | `null` | no |
 | <a name="input_enable_cloudwatch_logging"></a> [enable\_cloudwatch\_logging](#input\_enable\_cloudwatch\_logging) | Determines whether CloudWatch logging is configured for this container definition. Set to `false` to use other logging drivers | `bool` | `true` | no |
 | <a name="input_enable_execute_command"></a> [enable\_execute\_command](#input\_enable\_execute\_command) | Specifies whether to enable Amazon ECS Exec for the tasks within the service | `bool` | `false` | no |
-| <a name="input_entrypoint"></a> [entrypoint](#input\_entrypoint) | The entry point that is passed to the container | `list(string)` | `[]` | no |
-| <a name="input_environment"></a> [environment](#input\_environment) | The environment variables to pass to the container | <pre>list(object({<br/>    name  = string<br/>    value = string<br/>  }))</pre> | `[]` | no |
-| <a name="input_environmentFiles"></a> [environmentFiles](#input\_environmentFiles) | A list of files containing the environment variables to pass to a container | <pre>list(object({<br/>    value = string<br/>    type  = string<br/>  }))</pre> | `[]` | no |
+| <a name="input_entrypoint"></a> [entrypoint](#input\_entrypoint) | The entry point that is passed to the container | `list(string)` | `null` | no |
+| <a name="input_environment"></a> [environment](#input\_environment) | The environment variables to pass to the container | <pre>list(object({<br/>    name  = string<br/>    value = string<br/>  }))</pre> | `null` | no |
+| <a name="input_environmentFiles"></a> [environmentFiles](#input\_environmentFiles) | A list of files containing the environment variables to pass to a container | <pre>list(object({<br/>    value = string<br/>    type  = string<br/>  }))</pre> | `null` | no |
 | <a name="input_essential"></a> [essential](#input\_essential) | If the `essential` parameter of a container is marked as `true`, and that container fails or stops for any reason, all other containers that are part of the task are stopped | `bool` | `null` | no |
 | <a name="input_extraHosts"></a> [extraHosts](#input\_extraHosts) | A list of hostnames and IP address mappings to append to the `/etc/hosts` file on the container | <pre>list(object({<br/>    hostname  = string<br/>    ipAddress = string<br/>  }))</pre> | `null` | no |
 | <a name="input_firelensConfiguration"></a> [firelensConfiguration](#input\_firelensConfiguration) | The FireLens configuration for the container. This is used to specify and configure a log router for container logs. For more information, see [Custom Log Routing](https://docs.aws.amazon.com/AmazonECS/latest/developerguide/using_firelens.html) in the Amazon Elastic Container Service Developer Guide | <pre>object({<br/>    options = optional(map(string))<br/>    type    = optional(string)<br/>  })</pre> | `null` | no |
@@ -170,7 +170,7 @@ No modules.
 | <a name="input_logConfiguration"></a> [logConfiguration](#input\_logConfiguration) | The log configuration for the container. For more information see [LogConfiguration](https://docs.aws.amazon.com/AmazonECS/latest/APIReference/API_LogConfiguration.html) | <pre>object({<br/>    logDriver = optional(string)<br/>    options   = optional(map(string))<br/>    secretOptions = optional(list(object({<br/>      name      = string<br/>      valueFrom = string<br/>    })))<br/>  })</pre> | `{}` | no |
 | <a name="input_memory"></a> [memory](#input\_memory) | The amount (in MiB) of memory to present to the container. If your container attempts to exceed the memory specified here, the container is killed. The total amount of memory reserved for all containers within a task must be lower than the task `memory` value, if one is specified | `number` | `null` | no |
 | <a name="input_memoryReservation"></a> [memoryReservation](#input\_memoryReservation) | The soft limit (in MiB) of memory to reserve for the container. When system memory is under heavy contention, Docker attempts to keep the container memory to this soft limit. However, your container can consume more memory when it needs to, up to either the hard limit specified with the `memory` parameter (if applicable), or all of the available memory on the container instance | `number` | `null` | no |
-| <a name="input_mountPoints"></a> [mountPoints](#input\_mountPoints) | The mount points for data volumes in your container | <pre>list(object({<br/>    containerPath = optional(string)<br/>    readOnly      = optional(bool)<br/>    sourceVolume  = optional(string)<br/>  }))</pre> | `[]` | no |
+| <a name="input_mountPoints"></a> [mountPoints](#input\_mountPoints) | The mount points for data volumes in your container | <pre>list(object({<br/>    containerPath = optional(string)<br/>    readOnly      = optional(bool)<br/>    sourceVolume  = optional(string)<br/>  }))</pre> | `null` | no |
 | <a name="input_name"></a> [name](#input\_name) | The name of a container. If you're linking multiple containers together in a task definition, the name of one container can be entered in the links of another container to connect the containers. Up to 255 letters (uppercase and lowercase), numbers, underscores, and hyphens are allowed | `string` | `null` | no |
 | <a name="input_operating_system_family"></a> [operating\_system\_family](#input\_operating\_system\_family) | The OS family for task | `string` | `"LINUX"` | no |
 | <a name="input_portMappings"></a> [portMappings](#input\_portMappings) | The list of port mappings for the container. Port mappings allow containers to access ports on the host container instance to send or receive traffic. For task definitions that use the awsvpc network mode, only specify the containerPort. The hostPort can be left blank or it must be the same value as the containerPort | <pre>list(object({<br/>    appProtocol        = optional(string)<br/>    containerPort      = optional(number)<br/>    containerPortRange = optional(string)<br/>    hostPort           = optional(number)<br/>    name               = optional(string)<br/>    protocol           = optional(string)<br/>  }))</pre> | `null` | no |
@@ -180,17 +180,17 @@ No modules.
 | <a name="input_region"></a> [region](#input\_region) | Region where the resource(s) will be managed. Defaults to the Region set in the provider configuration | `string` | `null` | no |
 | <a name="input_repositoryCredentials"></a> [repositoryCredentials](#input\_repositoryCredentials) | Container repository credentials; required when using a private repo.  This map currently supports a single key; "credentialsParameter", which should be the ARN of a Secrets Manager's secret holding the credentials | <pre>object({<br/>    credentialsParameter = optional(string)<br/>  })</pre> | `null` | no |
 | <a name="input_resourceRequirements"></a> [resourceRequirements](#input\_resourceRequirements) | The type and amount of a resource to assign to a container. The only supported resource is a GPU | <pre>list(object({<br/>    type  = string<br/>    value = string<br/>  }))</pre> | `null` | no |
-| <a name="input_restartPolicy"></a> [restartPolicy](#input\_restartPolicy) | Container restart policy; helps overcome transient failures faster and maintain task availability | <pre>object({<br/>    enabled              = optional(bool)<br/>    ignoredExitCodes     = optional(list(number))<br/>    restartAttemptPeriod = optional(number)<br/>  })</pre> | <pre>{<br/>  "enabled": true<br/>}</pre> | no |
+| <a name="input_restartPolicy"></a> [restartPolicy](#input\_restartPolicy) | Container restart policy; helps overcome transient failures faster and maintain task availability | <pre>object({<br/>    enabled              = optional(bool, true)<br/>    ignoredExitCodes     = optional(list(number))<br/>    restartAttemptPeriod = optional(number)<br/>  })</pre> | <pre>{<br/>  "enabled": true<br/>}</pre> | no |
 | <a name="input_secrets"></a> [secrets](#input\_secrets) | The secrets to pass to the container. For more information, see [Specifying Sensitive Data](https://docs.aws.amazon.com/AmazonECS/latest/developerguide/specifying-sensitive-data.html) in the Amazon Elastic Container Service Developer Guide | <pre>list(object({<br/>    name      = string<br/>    valueFrom = string<br/>  }))</pre> | `null` | no |
 | <a name="input_service"></a> [service](#input\_service) | The name of the service that the container definition is associated with. Used in CloudWatch log group default name (if one is not provided) | `string` | `null` | no |
 | <a name="input_startTimeout"></a> [startTimeout](#input\_startTimeout) | Time duration (in seconds) to wait before giving up on resolving dependencies for a container | `number` | `30` | no |
 | <a name="input_stopTimeout"></a> [stopTimeout](#input\_stopTimeout) | Time duration (in seconds) to wait before the container is forcefully killed if it doesn't exit normally on its own | `number` | `120` | no |
-| <a name="input_systemControls"></a> [systemControls](#input\_systemControls) | A list of namespaced kernel parameters to set in the container | <pre>list(object({<br/>    namespace = optional(string)<br/>    value     = optional(string)<br/>  }))</pre> | `[]` | no |
+| <a name="input_systemControls"></a> [systemControls](#input\_systemControls) | A list of namespaced kernel parameters to set in the container | <pre>list(object({<br/>    namespace = optional(string)<br/>    value     = optional(string)<br/>  }))</pre> | `null` | no |
 | <a name="input_tags"></a> [tags](#input\_tags) | A map of tags to add to all resources | `map(string)` | `{}` | no |
 | <a name="input_ulimits"></a> [ulimits](#input\_ulimits) | A list of ulimits to set in the container. If a ulimit value is specified in a task definition, it overrides the default values set by Docker | <pre>list(object({<br/>    hardLimit = number<br/>    name      = string<br/>    softLimit = number<br/>  }))</pre> | `null` | no |
 | <a name="input_user"></a> [user](#input\_user) | The user to run as inside the container. Can be any of these formats: user, user:group, uid, uid:gid, user:gid, uid:group. The default (null) will use the container's configured `USER` directive or root if not set | `string` | `null` | no |
 | <a name="input_versionConsistency"></a> [versionConsistency](#input\_versionConsistency) | Specifies whether Amazon ECS will resolve the container image tag provided in the container definition to an image digest | `string` | `"disabled"` | no |
-| <a name="input_volumesFrom"></a> [volumesFrom](#input\_volumesFrom) | Data volumes to mount from another container | <pre>list(object({<br/>    readOnly        = optional(bool)<br/>    sourceContainer = optional(string)<br/>  }))</pre> | `[]` | no |
+| <a name="input_volumesFrom"></a> [volumesFrom](#input\_volumesFrom) | Data volumes to mount from another container | <pre>list(object({<br/>    readOnly        = optional(bool)<br/>    sourceContainer = optional(string)<br/>  }))</pre> | `null` | no |
 | <a name="input_workingDirectory"></a> [workingDirectory](#input\_workingDirectory) | The working directory to run commands inside the container | `string` | `null` | no |
 
 ## Outputs

modules/container-definition/main.tf

@@ -33,6 +33,9 @@ locals {
   # tflint-ignore: terraform_naming_convention
   linuxParameters = var.enable_execute_command ? merge(local.trimedLinuxParameters, { "initProcessEnabled" : true }) : merge({ "initProcessEnabled" : false }, local.trimedLinuxParameters)
 
+  # tflint-ignore: terraform_naming_convention
+  trimmedRestartPolicy = { for k, v in var.restartPolicy : k => v if v != null }
+
   definition = {
     command                = var.command
     cpu                    = var.cpu
@@ -42,9 +45,9 @@ locals {
     dnsServers             = local.is_not_windows ? var.dnsServers : null
     dockerLabels           = var.dockerLabels
     dockerSecurityOptions  = var.dockerSecurityOptions
-    entrypoint             = var.entrypoint
-    environment            = var.environment
-    environmentFiles       = var.environmentFiles
+    entrypoint             = var.entrypoint != null ? var.entrypoint : null
+    environment            = var.environment != null ? var.environment : null
+    environmentFiles       = var.environmentFiles != null ? var.environmentFiles : null
     essential              = var.essential
     extraHosts             = local.is_not_windows ? var.extraHosts : null
     firelensConfiguration  = var.firelensConfiguration != null ? { for k, v in var.firelensConfiguration : k => v if v != null } : null
@@ -57,23 +60,23 @@ locals {
     logConfiguration       = length(local.logConfiguration) > 0 ? local.logConfiguration : null
     memory                 = var.memory
     memoryReservation      = var.memoryReservation
-    mountPoints            = var.mountPoints
+    mountPoints            = var.mountPoints != null ? var.mountPoints : null
     name                   = var.name
     portMappings           = var.portMappings != null ? [for p in var.portMappings : { for k, v in p : k => v if v != null }] : null
     privileged             = local.is_not_windows ? var.privileged : null
     pseudoTerminal         = var.pseudoTerminal
     readonlyRootFilesystem = local.is_not_windows ? var.readonlyRootFilesystem : null
     repositoryCredentials  = var.repositoryCredentials
     resourceRequirements   = var.resourceRequirements
-    restartPolicy          = { for k, v in var.restartPolicy : k => v if v != null }
+    restartPolicy          = local.trimmedRestartPolicy.enabled ? local.trimmedRestartPolicy : null
     secrets                = var.secrets
     startTimeout           = var.startTimeout
     stopTimeout            = var.stopTimeout
-    systemControls         = var.systemControls
+    systemControls         = var.systemControls != null ? var.systemControls : null
     ulimits                = local.is_not_windows ? var.ulimits : null
     user                   = local.is_not_windows ? var.user : null
     versionConsistency     = var.versionConsistency
-    volumesFrom            = var.volumesFrom
+    volumesFrom            = var.volumesFrom != null ? var.volumesFrom : null
     workingDirectory       = var.workingDirectory
   }
 

modules/container-definition/variables.tf

@@ -89,8 +89,7 @@ variable "enable_execute_command" {
 variable "entrypoint" {
   description = "The entry point that is passed to the container"
   type        = list(string)
-  default     = []
-  nullable    = false
+  default     = null
 }
 
 variable "environment" {
@@ -99,8 +98,7 @@ variable "environment" {
     name  = string
     value = string
   }))
-  default  = []
-  nullable = false
+  default = null
 }
 
 # tflint-ignore: terraform_naming_convention
@@ -110,8 +108,7 @@ variable "environmentFiles" {
     value = string
     type  = string
   }))
-  default  = []
-  nullable = false
+  default = null
 }
 
 variable "essential" {
@@ -241,8 +238,7 @@ variable "mountPoints" {
     readOnly      = optional(bool)
     sourceVolume  = optional(string)
   }))
-  default  = []
-  nullable = false
+  default = null
 }
 
 variable "name" {
@@ -311,13 +307,14 @@ variable "resourceRequirements" {
 variable "restartPolicy" {
   description = "Container restart policy; helps overcome transient failures faster and maintain task availability"
   type = object({
-    enabled              = optional(bool)
+    enabled              = optional(bool, true)
     ignoredExitCodes     = optional(list(number))
     restartAttemptPeriod = optional(number)
   })
   default = {
     enabled = true
   }
+  nullable = false
 }
 
 variable "secrets" {
@@ -350,8 +347,7 @@ variable "systemControls" {
     namespace = optional(string)
     value     = optional(string)
   }))
-  default  = []
-  nullable = false
+  default = null
 }
 
 variable "ulimits" {
@@ -385,8 +381,7 @@ variable "volumesFrom" {
     readOnly        = optional(bool)
     sourceContainer = optional(string)
   }))
-  default  = []
-  nullable = false
+  default = null
 }
 
 # tflint-ignore: terraform_naming_convention