fix(controller): make creator label DNS compliant. Fixes #4880

USERS.md

@@ -70,6 +70,7 @@ Currently, the following organizations are **officially** using Argo Workflows:
 1. [Microblink](https://microblink.com/)
 1. [Mirantis](https://mirantis.com/)
 1. [Mixpanel](https://mixpanel.com)
+1. [Motus](https://www.motus.com)
 1. [New Relic](https://newrelic.com/)
 1. [Nikkei](https://www.nikkei.co.jp/nikkeiinfo/en/)
 1. [Norwegian Refugee Council](https://www.nrc.no/)

workflow/creator/creator.go

@@ -24,9 +24,10 @@ func Label(ctx context.Context, obj metav1.Object) {
 
 func dnsFriendly(s string) string {
 	value := regexp.MustCompile("[^-_.a-z0-9A-Z]").ReplaceAllString(s, "-")
+	value = regexp.MustCompile("^[^a-z0-9A-Z]*").ReplaceAllString(value, "")
+	value = regexp.MustCompile("[^a-z0-9A-Z]*$").ReplaceAllString(value, "")
 	if len(value) > 63 {
 		value = value[len(value)-63:]
 	}
-	value = strings.TrimLeft(value, "-")
 	return value
 }

workflow/creator/creator_test.go

@@ -36,4 +36,11 @@ func TestLabel(t *testing.T) {
 			assert.Equal(t, "y", wf.Labels[common.LabelKeyCreator])
 		}
 	})
+	t.Run("InvalidDNSNames", func(t *testing.T) {
+		wf := &wfv1.Workflow{}
+		Label(context.WithValue(context.TODO(), auth.ClaimsKey, &types.Claims{Claims: jwt.Claims{Subject: "!@#$%^&*()--__" + strings.Repeat("y", 35) + "__--!@#$%^&*()"}}), wf)
+		if assert.NotEmpty(t, wf.Labels) {
+			assert.Equal(t, strings.Repeat("y", 35), wf.Labels[common.LabelKeyCreator])
+		}
+	})
 }