cmd/k8s-operator,k8s-operator: allow users to set custom labels for the optional ServiceMonitor (#14475)

* cmd/k8s-operator,k8s-operator: allow users to set custom labels for the optional ServiceMonitor

Updates tailscale/tailscale#14381

Signed-off-by: Irbe Krumina <irbe@tailscale.com>

k8s-operator/apis/v1alpha1/types_proxyclass.go

@@ -87,7 +87,7 @@ type StatefulSet struct {
 	// Label keys and values must be valid Kubernetes label keys and values.
 	// https://kubernetes.io/docs/concepts/overview/working-with-objects/labels/#syntax-and-character-set
 	// +optional
-	Labels map[string]string `json:"labels,omitempty"`
+	Labels Labels `json:"labels,omitempty"`
 	// Annotations that will be added to the StatefulSet created for the proxy.
 	// Any Annotations specified here will be merged with the default annotations
 	// applied to the StatefulSet by the Tailscale Kubernetes operator as
@@ -109,7 +109,7 @@ type Pod struct {
 	// Label keys and values must be valid Kubernetes label keys and values.
 	// https://kubernetes.io/docs/concepts/overview/working-with-objects/labels/#syntax-and-character-set
 	// +optional
-	Labels map[string]string `json:"labels,omitempty"`
+	Labels Labels `json:"labels,omitempty"`
 	// Annotations that will be added to the proxy Pod.
 	// Any annotations specified here will be merged with the default
 	// annotations applied to the Pod by the Tailscale Kubernetes operator.
@@ -188,8 +188,34 @@ type Metrics struct {
 type ServiceMonitor struct {
 	// If Enable is set to true, a Prometheus ServiceMonitor will be created. Enable can only be set to true if metrics are enabled.
 	Enable bool `json:"enable"`
+	// Labels to add to the ServiceMonitor.
+	// Labels must be valid Kubernetes labels.
+	// https://kubernetes.io/docs/concepts/overview/working-with-objects/labels/#syntax-and-character-set
+	// +optional
+	Labels Labels `json:"labels"`
 }
 
+type Labels map[string]LabelValue
+
+func (l Labels) Parse() map[string]string {
+	if l == nil {
+		return nil
+	}
+	m := make(map[string]string, len(l))
+	for k, v := range l {
+		m[k] = string(v)
+	}
+	return m
+}
+
+// We do not validate the values of the label keys here - it is done by the ProxyClass
+// reconciler because the validation rules are too complex for a CRD validation markers regex.
+
+// +kubebuilder:validation:Type=string
+// +kubebuilder:validation:Pattern=`^(([a-zA-Z0-9][-._a-zA-Z0-9]*)?[a-zA-Z0-9])?$`
+// +kubebuilder:validation:MaxLength=63
+type LabelValue string
+
 type Container struct {
 	// List of environment variables to set in the container.
 	// https://kubernetes.io/docs/reference/kubernetes-api/workload-resources/pod-v1/#environment-variables

k8s-operator/apis/v1alpha1/zz_generated.deepcopy.go

@@ -316,13 +316,34 @@ func (in *Env) DeepCopy() *Env {
 	return out
 }
 
+// DeepCopyInto is an autogenerated deepcopy function, copying the receiver, writing into out. in must be non-nil.
+func (in Labels) DeepCopyInto(out *Labels) {
+	{
+		in := &in
+		*out = make(Labels, len(*in))
+		for key, val := range *in {
+			(*out)[key] = val
+		}
+	}
+}
+
+// DeepCopy is an autogenerated deepcopy function, copying the receiver, creating a new Labels.
+func (in Labels) DeepCopy() Labels {
+	if in == nil {
+		return nil
+	}
+	out := new(Labels)
+	in.DeepCopyInto(out)
+	return *out
+}
+
 // DeepCopyInto is an autogenerated deepcopy function, copying the receiver, writing into out. in must be non-nil.
 func (in *Metrics) DeepCopyInto(out *Metrics) {
 	*out = *in
 	if in.ServiceMonitor != nil {
 		in, out := &in.ServiceMonitor, &out.ServiceMonitor
 		*out = new(ServiceMonitor)
-		**out = **in
+		(*in).DeepCopyInto(*out)
 	}
 }
 
@@ -391,7 +412,7 @@ func (in *Pod) DeepCopyInto(out *Pod) {
 	*out = *in
 	if in.Labels != nil {
 		in, out := &in.Labels, &out.Labels
-		*out = make(map[string]string, len(*in))
+		*out = make(Labels, len(*in))
 		for key, val := range *in {
 			(*out)[key] = val
 		}
@@ -999,6 +1020,13 @@ func (in *S3Secret) DeepCopy() *S3Secret {
 // DeepCopyInto is an autogenerated deepcopy function, copying the receiver, writing into out. in must be non-nil.
 func (in *ServiceMonitor) DeepCopyInto(out *ServiceMonitor) {
 	*out = *in
+	if in.Labels != nil {
+		in, out := &in.Labels, &out.Labels
+		*out = make(Labels, len(*in))
+		for key, val := range *in {
+			(*out)[key] = val
+		}
+	}
 }
 
 // DeepCopy is an autogenerated deepcopy function, copying the receiver, creating a new ServiceMonitor.
@@ -1016,7 +1044,7 @@ func (in *StatefulSet) DeepCopyInto(out *StatefulSet) {
 	*out = *in
 	if in.Labels != nil {
 		in, out := &in.Labels, &out.Labels
-		*out = make(map[string]string, len(*in))
+		*out = make(Labels, len(*in))
 		for key, val := range *in {
 			(*out)[key] = val
 		}