Truncate UI service name if over 63 characters

Signed-off-by: Jacob Salway <[email protected]>

pkg/util/sparkapplication.go

@@ -17,6 +17,7 @@ limitations under the License.
 package util
 
 import (
+	"crypto/md5"
 	"fmt"
 	"reflect"
 	"strings"
@@ -156,7 +157,16 @@ func GetExecutorLocalVolumeMounts(app *v1beta2.SparkApplication) []corev1.Volume
 }
 
 func GetDefaultUIServiceName(app *v1beta2.SparkApplication) string {
-	return fmt.Sprintf("%s-ui-svc", app.Name)
+	preferredName := fmt.Sprintf("%s-ui-svc", app.Name)
+
+	// Service names are used as DNS labels, so must be 63 characters or shorter
+	if len(preferredName) <= 63 {
+		return preferredName
+	}
+
+	// Truncate the name and append a hash to ensure uniqueness while staying below the limit
+	hash := fmt.Sprintf("%x", md5.Sum([]byte(preferredName)))
+	return fmt.Sprintf("%s-%s-ui-svc", app.Name[:47], hash[:8])
 }
 
 func GetDefaultUIIngressName(app *v1beta2.SparkApplication) string {

pkg/util/sparkapplication_test.go

@@ -284,6 +284,20 @@ var _ = Describe("GetDefaultUIServiceName", func() {
 	It("Should return the default UI service name", func() {
 		Expect(util.GetDefaultUIServiceName(app)).To(Equal("test-app-ui-svc"))
 	})
+
+	appWithLongName := &v1beta2.SparkApplication{
+		ObjectMeta: metav1.ObjectMeta{
+			Name:      "test-app-with-a-long-name-that-would-be-over-63-characters",
+			Namespace: "test-namespace",
+		},
+	}
+
+	It("Should truncate the app name so the service name is below 63 characters", func() {
+		serviceName := util.GetDefaultUIServiceName(appWithLongName)
+		Expect(len(serviceName)).To(BeNumerically("<=", 63))
+		Expect(serviceName).To(HavePrefix(appWithLongName.Name[:47]))
+		Expect(serviceName).To(HaveSuffix("-ui-svc"))
+	})
 })
 
 var _ = Describe("GetDefaultUIIngressName", func() {