Error decoding JSON: json: cannot unmarshal bool into Go struct field of type string

Hello!

The mesh-task submodule intakes a variable called log_configuration, to customize/configure logs for an ECS task built by this module. The variable is added to the merged container_definitions object for the generated ecs_task_definition resource.

Variable definition: https://github.com/hashicorp/terraform-aws-consul-ecs/blob/354c2157db4144ce254218025da5bb88edf66f00/modules/mesh-task/variables.tf#L120-L124

Appended value: https://github.com/hashicorp/terraform-aws-consul-ecs/blob/354c2157db4144ce254218025da5bb88edf66f00/modules/mesh-task/main.tf#L189

The AWS Developer guide includes an options block for logConfiguration that includes a setting for awslogs-create-group with values of true/false, to determine whether the task definition creates the Cloudwatch logs group, or references the defined values instead. Snippet below:

https://docs.aws.amazon.com/AmazonECS/latest/developerguide/using_awslogs.html

                "options": {
                    "awslogs-group": "firelens-container",
                    "awslogs-region": "us-west-2",
                    "awslogs-create-group": "true",
                    "awslogs-stream-prefix": "firelens"

In my code, I have created a mesh-task:

variable "awslogs_create_group" {
  type    = bool
  default = true
}

# Object to add to log_configuration's "options" sub-block.
locals {
  logs_options = {

. . . 

    awslogs-create-group  = var.awslogs_create_group

. . . 

  }
}

module "mesh_task" {

. . .

  log_configuration = {
    logDriver = "awslogs"
    options   = local.logs_options
  }

. . . 
}

This module invocation returns a go struct error during terraform plan

Error: ECS Task Definition container_definitions is invalid: Error decoding JSON: json: cannot unmarshal bool into Go struct field LogConfiguration.LogConfiguration.Options of type string

│   with module..module.mesh_task["task"].aws_ecs_task_definition.this,
│   on .terraform/modules//modules/mesh-task/main.tf line 180, in resource "aws_ecs_task_definition" "this":
│  180:   container_definitions = jsonencode(
│  181:     flatten(
│  182:       concat(
│  183:         local.container_defs_with_depends_on,
│  184:         [

. . . 

│  220:             logConfiguration = var.log_configuration

Changing awslogs-create-group's value from bool(true), to string(true) (Or, true -> "true") fixes this error to let the task definition create the cloudwatch group.

Looking at the log_configuration declaration, it seems like there isn't type checking or validation on the variable. There are validations for other variables: For example, the upstreams variable in variables.tf

Could it make sense to create an object definition for log_configuration, with a validation? Example below (Note: This is a rough suggestion, using existing validations in the module as reference)

variable "log_configuration" {
  type = object({
    logDriver = string
    options = object({
      awslogs-group         = string
      awslogs-region        = string
      awslogs-stream-prefix = string
      awslogs-create-group  = string
    })
  })
  validation {
    error_message = "awslogs-create-group must be a string 'true'"
    condition = allfalse(flatten([
      for log_var in var.log_configuration : [
        type(can(lookup(log_var.options, "awslogs-create-group"), string))
      ]
    ]))
  }
}

I couldn't find information on the available task definition values to configure in the mesh-task module, and relied on the ecs_task_definition resource, and this module's variables file to understand how to build the ECS task definition. Since some of the larger variables (log_configuration, container_definitions, volumes) are set to a type of any, it required some context switching to fully understand what was needed to get the mesh-task created, in addition to this specific error.

Thank you! 😺

hashicorp / terraform-aws-consul-ecs

Error decoding JSON: json: cannot unmarshal bool into Go struct field of type string #91