r/lb_target_group: Don't allow invalid configurations

[YakDriver]

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Description

Invalid aws_lb_target_group configurations were allowed in AWS provider 3.9 and before. In order to allow invalid configurations, the resource had error-avoiding logic in CustomizeDiff, Read, and Update. This logic was removed with 3.10 which broke the invalid configurations. The logic was added back (#15613) to avoid breaking invalid configurations. This logic should be removed.

The aws_lb_target_group can be fixed (not allowing invalid configurations) by following these steps (basically just undoing #15613):

1. Remove the DiffSuppressFunc from stickiness.type
2. in resourceAwsLbTargetGroupUpdate(), in if d.HasChange("stickiness"), remove the if statement if !stickiness["enabled"].(bool) && stickiness["type"].(string) == "lb_cookie".... DO NOT remove the else body: remove the if statement, the if body, and the else statement, and associated braces.
3. In flattenAwsLbTargetGroupStickiness(), remove the if !stickinessMap["enabled"].(bool) && stickinessMap["type"].(string) statement, the if body, and the else word. Leave if err := d.Set("stickiness"...

New or Affected Resource(s)

• aws_lb_target_group

Potential Terraform Configuration

This invalid configuration should result in an error even though the stickiness is disabled (consistent with the AWS API). This is invalid because the TCP protocol is not compatible with stickiness type of lb_cookie.

Invalid Config, Should Cause Error

resource "aws_lb_target_group" "test" {
   protocol = "TCP" # or "UDP", "TCP_UDP", or "TLS"
   # other config

   stickiness {
     type    = "lb_cookie"
     enabled = false
   }
 }

Invalid Config, Does Cause Error

resource "aws_lb_target_group" "test" {
   protocol = "HTTP" # or "HTTPS"
   # other config

   stickiness {
     type    = "source_ip"
     enabled = false
   }
 }

Valid Config, Should Not Cause Error

resource "aws_lb_target_group" "test" {
   protocol = "TCP" # or "UDP", "TCP_UDP", or "TLS"
   # other config

   stickiness {
     type    = "source_ip"
     enabled = false
   }
 }

Valid Config, Should Not Cause Error

resource "aws_lb_target_group" "test" {
   protocol = "HTTP" # or "HTTPS"
   # other config

   stickiness {
     type    = "lb_cookie"
     enabled = false
   }
 }

References

• Can't create a load balancer target group for network load balancer #9050
• Error: Network Load Balancers do not support Stickiness #9093
• aws_lb_target_group with aws_lb (unable to disable stickiness not supported in NLB) #10494
• Network Load Balancer stickiness not configurable with Terraform (but supported by AWS) #12726
• Add source_ip as a valid stickiness type for aws_lb_target_group #13762
• NLB Stickiness conflicts between UDP & TCP #14556
• Add stickiness support for NLB target_groups #15295
• Stickiness support for source_ip broke valid configurations for NLB #15603
• r/lb_target_group: Don't allow invalid configurations #15612
• lb_target_group: Allow invalid stickiness config, avoid breaking change #15613

[YakDriver]

Potentially helpful notes for this resource that I'll leave here:

ALB = HTTP, HTTPS
deregistration_delay.timeout_seconds
stickiness.enabled
stickiness.type = lb_cookie
load_balancing.algorithm.type
slow_start.duration_seconds
stickiness.lb_cookie.duration_seconds

NLB = TCP, UDP, TCP_UDP
deregistration_delay.timeout_seconds
stickiness.enabled
stickiness.type = source_ip
proxy_protocol_v2.enabled

NLB = TLS
deregistration_delay.timeout_seconds
stickiness.enabled = false
stickiness.type = source_ip
proxy_protocol_v2.enabled

[github-actions]

This functionality has been released in v4.0.0 of the Terraform AWS Provider. Please see the Terraform documentation on provider versioning or reach out if you need any assistance upgrading.

For further feature requests or bug reports with this functionality, please create a new GitHub issue following the template. Thank you!

[github-actions]

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