fix: Fix EKS cluster name regex

[acwwat]

Description

This PR is to fix the regex pattern for the EKS cluster name that is included in the documentation for numerous EKS-related resources.

I'd also like to ask the maintainers to see whether it makes sense to just remove the regex from the non-cluster resource docs. Once the EKS cluster is created (and it makes sense to provide the regex there), the name is simply referenced by other resources so I don't think providing the exact format is super useful. Let me know what you think - I can update the PR to remove them if you think it makes sense. Thanks.

Relations

Closes #35843

References

Referred to the API reference for the cluster name regex.

Output from Acceptance Testing

$ make testacc TESTS=TestValidClusterName PKG=eks
==> Checking that code complies with gofmt requirements...
TF_ACC=1 go test ./internal/service/eks/... -v -count 1 -parallel 20 -run='TestValidClusterName'  -timeout 360m
=== RUN   TestValidClusterName
=== PAUSE TestValidClusterName
=== CONT  TestValidClusterName
--- PASS: TestValidClusterName (0.00s)
PASS
ok      github.com/hashicorp/terraform-provider-aws/internal/service/eks        0.186s

$

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[mattburgess]

Looks like the validation function is actually incorrect as well.

Feel free to include the following change in this PR @acwwat :

diff --git a/internal/service/eks/validate.go b/internal/service/eks/validate.go
index 9195a044cb..3bb4b598c6 100644
--- a/internal/service/eks/validate.go
+++ b/internal/service/eks/validate.go
@@ -17,7 +17,7 @@ func validClusterName(v interface{}, k string) (ws []string, errors []error) {
        }
 
        // https://docs.aws.amazon.com/eks/latest/APIReference/API_CreateCluster.html#API_CreateCluster_RequestSyntax
-       pattern := `^[0-9A-Za-z][0-9A-Za-z_-]+$`
+       pattern := `^[0-9A-Za-z][0-9A-Za-z_-]*$`
        if !regexache.MustCompile(pattern).MatchString(value) {
                errors = append(errors, fmt.Errorf(
                        "%q doesn't comply with restrictions (%q): %q",
diff --git a/internal/service/eks/validate_test.go b/internal/service/eks/validate_test.go
index f6627cc653..777f7aa024 100644
--- a/internal/service/eks/validate_test.go
+++ b/internal/service/eks/validate_test.go
@@ -20,6 +20,10 @@ func TestValidClusterName(t *testing.T) {
                        Value:    "my-valid-eks-cluster_1_dev",
                        ErrCount: 0,
                },
+               {
+                       Value:    "a",
+                       ErrCount: 0,
+               },
                {
                        Value:    `_invalid`,
                        ErrCount: 1,

The new test fails on current main:

$ make testacc TESTS=TestValidClusterName PKG=eks
==> Checking that code complies with gofmt requirements...
TF_ACC=1 go test ./internal/service/eks/... -v -count 1 -parallel 20 -run='TestValidClusterName'  -timeout 360m
=== RUN   TestValidClusterName
=== PAUSE TestValidClusterName
=== CONT  TestValidClusterName
    validate_test.go:65: Expected the EKS Cluster Name to trigger a validation error: a, expected 0, got 1 errors
--- FAIL: TestValidClusterName (0.00s)
FAIL
FAIL	github.com/hashicorp/terraform-provider-aws/internal/service/eks	0.362s
FAIL
make: *** [GNUmakefile:359: testacc] Error 1

And passes with the regex change applied:

$ make testacc TESTS=TestValidClusterName PKG=eks
==> Checking that code complies with gofmt requirements...
TF_ACC=1 go test ./internal/service/eks/... -v -count 1 -parallel 20 -run='TestValidClusterName'  -timeout 360m
=== RUN   TestValidClusterName
=== PAUSE TestValidClusterName
=== CONT  TestValidClusterName
--- PASS: TestValidClusterName (0.00s)
PASS
ok  	github.com/hashicorp/terraform-provider-aws/internal/service/eks	0.330s

[mattburgess]

Oh, and as to your suggestion about removing the regex from all but the cluster resource docs I'd definitely agree although I'm a mere contributor not a maintainer.

[acwwat]

@mattburgess Thanks for catching the regex issue in the code. I've incorporated your suggested changes to the code. I've also decided to just remove the regex from the non-cluster resource docs for cleanliness and ease of maintenance going forward.

[ewbankkit]

LGTM 🚀.

[ewbankkit]

@acwwat Thanks for the contribution 🎉 👏.

[github-actions]

This functionality has been released in v5.38.0 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!

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