[BUG] Suppress diff for lambda target group attributes

[tomoikey]

Rollback Plan

If a change needs to be reverted, we will publish an updated version of the library.

Changes to Security Controls

Are there any changes to security controls (access controls, encryption, logging) in this pull request? If so, explain.

No changes to security controls.

Description

Fixes perpetual diff issue for Lambda target groups with stickiness, target_failover, and target_group_health attributes.

Lambda target type only supports lambda.multi_value_headers.enabled attribute. AWS API silently ignores stickiness, target_failover, and target_group_health configuration for Lambda target groups, but Terraform was detecting them as diffs. This means diffs will continue to appear indefinitely even after applying. Detecting diffs in the plan for changes that are not actually applied is undesirable.

This change adds DiffSuppressFunc to these three attributes to suppress diffs when target_type is lambda, using the existing suppressIfTargetType() helper function.

Before

  ~ update in-place
...
  ~ resource "aws_lb_target_group" "test" {
...
      ~ stickiness {
          + cookie_duration = 86400
          + enabled         = false
          + type            = "lb_cookie"
        }

      ~ target_failover {
          + on_deregistration = "no_rebalance"
          + on_unhealthy      = "no_rebalance"
        }

      ~ target_group_health {
          ~ dns_failover {
              + minimum_healthy_targets_count      = "off"
              + minimum_healthy_targets_percentage = "off"
            }
          ~ unhealthy_state_routing {
              + minimum_healthy_targets_count      = 1
              + minimum_healthy_targets_percentage = "off"
            }
        }
...
Plan: 0 to add, 1 to change, 0 to destroy.

After

No changes. Your infrastructure matches the configuration.

Terraform has compared your real infrastructure against your configuration and found no differences, so no changes
are needed.

Relations

None

References

The following target group attributes are supported if the target group type is instance or ip:
(omitted)

The following target group attribute is supported if the target group type is lambda:
(omitted)

• AWS ELBv2 Target Group Attributes Documentation

[github-actions]

✅ Thank you for correcting the previously detected issues! The maintainers appreciate your efforts to make the review process as smooth as possible.

[github-actions]

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