ECS Task Definition With SSM Params Injected Into `container_definition.tmpl`

container_definitions.tmpl

[
  {
    "name": "your_app",
    "image": "${image_repo_arn}:${image_tag}",
    "essential": true,
    "memoryReservation": 300,
    "portMappings": [
      {
        "hostPort": 80,
        "containerPort": 8000,
        "protocol": "tcp"
      }
    ],
    "environment": ${environments}
  }
]

main.tf

// ...

variable "environment_variables" {
  description = "Environment variables"
  type = map(string)
}
  
resource "aws_ecs_task_definition" "cocoon" {
  family = "your_app_${var.environment}"

  # Ref: https://www.terraform.io/docs/configuration/functions/templatefile.html
  container_definitions = templatefile("${path.module}/container_definitions.tmpl", {
    image_repo_arn = data.aws_ecr_repository.your_app_repo.arn
    image_tag = data.aws_ecr_image.your_app.image_tag
    environments = jsonencode([for key, value in var.environment_variables: {
      name: key,
      value: value
    }])
  })

  requires_compatibilities = [
    "EC2"]

  volume {
    // ...
  }
}