fix: Missing field LogConfiguration.LogDriver error when enable_cloudwatch_logging is false

[alisson276]

Description

If we pass enable_cloudwatch_logging = false on a service container_definitions section, it will generate this error below:

│ Error: creating ECS Task Definition (my-service): InvalidParameter: 1 validation error(s) found.
│ - missing required field, RegisterTaskDefinitionInput.ContainerDefinitions[0].LogConfiguration.LogDriver.
│ 
│ 
│   with module.ecs.module.service["my-container"].aws_ecs_task_definition.this[0],
│   on ../../modules/aws-compute-ecs/modules/service/main.tf line 608, in resource "aws_ecs_task_definition" "this":
│  608: resource "aws_ecs_task_definition" "this" {

Motivation and Context

This behavior happens because in the planning phase the logConfiguration is computed as {}, which is an invalid configuration when posting on AWS API.
My plan of a just imported resource is:

  # module.ecs.module.service["my-service"].aws_ecs_task_definition.this[0] must be replaced
+/- resource "aws_ecs_task_definition" "this" {
      ~ arn                      = "arn:aws:ecs:us-east-1:1234567891011:task-definition/my-service-definition:20" -> (known after apply)
      ~ arn_without_revision     = "arn:aws:ecs:us-east-1:1234567891011:task-definition/my-service-definition" -> (known after apply)
      ~ container_definitions    = jsonencode(
          ~ [
              ~ {
                  + logConfiguration  = {}
                  - mountPoints       = []
                    name              = "worker"
                  - portMappings      = []
                  - volumesFrom       = []
                    # (7 unchanged attributes hidden)
                },
            ] # forces replacement
        )

And this is computed this way because of a merge():

log_configuration = merge(
    { for k, v in {
      logDriver = "awslogs",
      options = {
        awslogs-region        = data.aws_region.current.name,
        awslogs-group         = try(aws_cloudwatch_log_group.this[0].name, ""),
        awslogs-stream-prefix = "ecs"
      },
    } : k => v if var.enable_cloudwatch_logging },
    var.log_configuration
  )

In the console, if all parameters to merge are null or empty, the result is an empty object:

> merge({}, null)
{}
> merge(null, null)
{}
> merge({}, {a = "A"})
{
  "a" = "A"
}
> length(merge({}, {a = "A"}))
1

Breaking Changes

No breaking change

How Has This Been Tested?

• I have updated at least one of the examples/* to demonstrate and validate my change(s)
• I have tested and validated these changes using one or more of the provided examples/* projects

• I have executed pre-commit run -a on my pull request

[bryantbiggs]

thanks for the fix!

[antonbabenko]

This PR is included in version 5.0.2 🎉

[github-actions]

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