6.21.0

What’s Changed

feat: add alb_internal_default_target_group_arn variable @thiago4go (#70)

## Add support for custom target group in internal ALB listener

Summary

Adds alb_internal_default_target_group_arn variable to allow users to specify a custom target group ARN for the internal ALB HTTPS listener default action.

Motivation

When using external deployment tools (e.g., GitHub Actions, CodeDeploy) that manage ALB listener routing, Terraform would revert the listener's default action back to the module-created default target group on subsequent runs. This change allows users to align Terraform configuration with externally managed listener configurations.

Changes

• Added alb_internal_default_target_group_arn variable to _variables.tf
• Modified alb-internal.tf to use the custom target group ARN when provided
• Falls back to module-created default target group when variable is empty (backward compatible)

Usage Example

hcl
module "ecs_cluster" {
source = "git::https://github.com/DNXLabs/terraform-aws-ecs.git?ref=6.20.1"

name = "my-cluster"
alb_internal = true
alb_internal_default_target_group_arn = "arn:aws:elasticloadbalancing:region:account:targetgroup/my-app/abc123"

... other variables

}

Backward Compatibility

Fully backward compatible. When alb_internal_default_target_group_arn is not set or empty, behavior remains unchanged.

Testing

• Verified variable defaults to empty string
• Confirmed ternary operator correctly selects custom ARN when provided
• Validated fallback to default target group when variable is empty

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