[Bug]: aws_lb_target_group resource is warning to not provide value when none was provided

[camway]

Terraform Core Version

1.3.1

AWS Provider Version

5.83.0

Affected Resource(s)

aws_lb_target_group

Expected Behavior

Create the target group with no warnings

Actual Behavior

Warning displayed at the end of the plan

Relevant Error/Panic Output Snippet

│ Warning: Invalid Attribute Combination
│ 
│   with module.firstMod.module.secondMod[0].aws_lb_target_group.tg,
│   on modules/internal_web/main.tf line 64, in resource "aws_lb_target_group" "tg":
│   64: resource "aws_lb_target_group" "tg" {
│ 
│ Attribute "protocol" cannot be specified when "target_type" is "lambda".
│ 
│ This will be an error in a future release.
│ 
│ (and 3 more similar warnings elsewhere)
╵

Terraform Configuration Files

As far as I can tell, this is the only relevant resource:

resource "aws_lb_target_group" "tg" {
  name        = var.name
  target_type = "lambda"
}

Steps to Reproduce

Setup a load balancer and attach a lambda target group to it.

Debug Output

If this turns out to be required, I can try. The output is very long and would take me a while to sanitize

Panic Output

None

Important Factoids

No response

References

No response

Would you like to implement a fix?

None

[github-actions]

Community Note

Voting for Prioritization

• Please vote on this issue by adding a 👍 reaction to the original post to help the community and maintainers prioritize this request.
• Please see our prioritization guide for information on how we prioritize.
• Please do not leave "+1" or other comments that do not add relevant new information or questions, they generate extra noise for issue followers and do not help prioritize the request.

Volunteering to Work on This Issue

• If you are interested in working on this issue, please leave a comment.
• If this would be your first contribution, please review the contribution guide.

[justinretzolk]

Hey @camway 👋 Thank you for taking the time to raise this! In order for the team or community to look into this, we'll need a sample configuration that can be used to reproduce this and/or debug logging (redacted as needed, as you mentioned).

For what it's worth, it may be worth reviewing the module that you're using to see if there's a configuration error within the module that's causing the protocol argument to be specified -- based on what you've provided so far, that's my first hunch.

[camway]

Hey @justinretzolk I think my issue may have been resolved. I'm trying to get through some much needed TF updates, and bumping the current TF version seems to have resolved this for me. The original issue I submitted was after updating to the new provider, but I hadn't updated TF proper. I just bumped it from 1.3.1 to 1.10.4, and this issue seems to have disappeared now.

Just in case it's useful, this is the expanded version of the original code I posted. There are no other conditional blocks or anything like that. I swapped some names, but I didn't remove any property or condition from any resource. My only guesses are that it either had protocol saved on the resource in the state, and that tripped up the plan, or it's inferring the protocol from the listener somehow (didn't think TF would do this, but I can't rule it out without reading the source).

resource "aws_lb_listener" "https" {
  load_balancer_arn = aws_lb.private.arn
  port              = "443"
  protocol          = "HTTPS"
  ssl_policy        = "ELBSecurityPolicy-2016-08"
  certificate_arn   = var.certificate_arn

  default_action {
    type = "fixed-response"

    fixed_response {
      content_type = "text/plain"
      message_body = "Page not found."
      status_code  = "404"
    }
  }
}

resource "aws_lb_listener_rule" "this" {
  listener_arn = aws_lb_listener.https.arn
  priority     = 10

  action {
    type             = "forward"
    target_group_arn = aws_lb_target_group.tg.arn
  }

  condition {
    path_pattern {
      values = ["/mylambda"]
    }
  }
}

resource "aws_lb_target_group" "tg" {
  name        = var.name
  target_type = "lambda"
}

resource "aws_lb_target_group_attachment" "lambda" {
  depends_on       = [aws_lambda_permission.with_lb]
  target_group_arn = aws_lb_target_group.tg.arn
  target_id        = "${module.mylambda.function_arn}:${module.mylambda.alias_name}"
}

Regardless I think I'm good now if you'd like to close this.

Thank you and take care!

[justinretzolk]

Thanks for the update @camway! I'm glad to hear you were able to sort this out. Since this seemed to be transient, I'm going to close the issue as you mentioned, but if you experience any further unexpected behavior, please do let us know!

Thanks again for taking the time to raise this, and good luck on you updates!

[github-actions]

Warning

This issue has been closed, meaning that any additional comments are hard for our team to see. Please assume that the maintainers will not see them.

Ongoing conversations amongst community members are welcome, however, the issue will be locked after 30 days. Moving conversations to another venue, such as the AWS Provider forum, is recommended. If you have additional concerns, please open a new issue, referencing this one where needed.