Fix: label values not validated (#355)

Updated changelog

CHANGELOG.md

@@ -10,6 +10,7 @@ Changelog for Cass Operator, new PRs should update the `main / unreleased` secti
 ```
 
 ## unreleased
+* [BUGFIX] [#355](https://github.com/k8ssandra/cass-operator/issues/335) Cleanse label names derived from cluster name, which can contain illegal chars for label names. 
 
 ## v1.11.0
 

pkg/oplabels/labels.go

@@ -5,8 +5,9 @@ package oplabels
 
 import (
 	"fmt"
-
 	api "github.com/k8ssandra/cass-operator/apis/cassandra/v1beta1"
+	"regexp"
+	"strings"
 )
 
 const (
@@ -17,16 +18,17 @@ const (
 	NameLabelValue             = "cassandra"
 	InstanceLabel              = "app.kubernetes.io/instance"
 	VersionLabel               = "app.kubernetes.io/version"
-	CreatedByLabel             = "app.kubernetes.io/created-by"
+	emptyString                = ""
+	labelCut                   = ".-_"
 )
 
+var blacklistRegex = regexp.MustCompile(`[^a-zA-Z\d_.-]`)
+
 func AddOperatorLabels(m map[string]string, dc *api.CassandraDatacenter) {
 	m[ManagedByLabel] = ManagedByLabelValue
 	m[NameLabel] = NameLabelValue
 	m[VersionLabel] = dc.Spec.ServerVersion
-
-	instanceName := fmt.Sprintf("cassandra-%s", dc.Spec.ClusterName)
-	m[InstanceLabel] = instanceName
+	m[InstanceLabel] = fmt.Sprintf("cassandra-%s", CleanLabelName(dc.Spec.ClusterName))
 
 	if len(dc.Spec.AdditionalLabels) != 0 {
 		for key, value := range dc.Spec.AdditionalLabels {
@@ -43,3 +45,12 @@ func HasManagedByCassandraOperatorLabel(m map[string]string) bool {
 	v, ok := m[ManagedByLabel]
 	return ok && v == ManagedByLabelValue
 }
+
+// CleanLabelName a valid label must be an empty string or consist of alphanumeric characters,
+// '-', '_' or '.', and must start and end with an alphanumeric.
+// Note: we apply a prefix of "cassandra-" to the cluster name value used as label name.
+// As such, empty string isn't a valid case.
+func CleanLabelName(labelName string) string {
+	trimLeft := strings.TrimLeft(blacklistRegex.ReplaceAllString(labelName, emptyString), labelCut)
+	return strings.TrimRight(trimLeft, labelCut)
+}

tests/add_operator_labels/add_operator_labels_suite_test.go

@@ -0,0 +1,42 @@
+package add_operator_labels
+
+import (
+	"github.com/k8ssandra/cass-operator/pkg/oplabels"
+	"github.com/stretchr/testify/require"
+	"testing"
+)
+
+/**
+A valid label must be an empty string or consist of alphanumeric characters,
+'-', '_' or '.', and must start and end with an alphanumeric.
+*/
+func TestLabelNameClean(t *testing.T) {
+
+	var cleaned = oplabels.CleanLabelName("+!*(-_)cor @#$%^&rect_ LABEL.name-1=<>_?,.")
+	require.EqualValues(t, "correct_LABEL.name-1", cleaned,
+		"expect label name w/ outlier blacklist chars to be cleaned")
+
+	cleaned = oplabels.CleanLabelName("cor!@#$%^&*()rect__ LABEL.name")
+	require.EqualValues(t, "correct__LABEL.name", cleaned,
+		"expect label name w/ inside blacklist chars to be cleaned")
+
+	cleaned = oplabels.CleanLabelName("correct")
+	require.EqualValues(t, "correct", cleaned,
+		"expect label name without blacklist chars to be correct")
+
+	cleaned = oplabels.CleanLabelName("")
+	require.EqualValues(t, "", cleaned,
+		"expect label name as empty without blacklist chars to be correct")
+
+	cleaned = oplabels.CleanLabelName("-_!@#$%-^&*.()<>?._-&*.")
+	require.EqualValues(t, "", cleaned,
+		"expect label name as empty as contains all blacklist chars")
+
+	cleaned = oplabels.CleanLabelName("-_!@#$%-^&*.()<>?._-&*.X")
+	require.EqualValues(t, "X", cleaned,
+		"expect label name as last char only")
+
+	cleaned = oplabels.CleanLabelName("Y-_!@#$%-^&*.()<>?._-&*.")
+	require.EqualValues(t, "Y", cleaned,
+		"expect label name as first char only")
+}