Add ability to reflect whitelisted labels

README.md

@@ -75,6 +75,8 @@ $ kubectl -n kube-system apply -f https://github.com/emberstack/kubernetes-refle
 
   - Add `reflector.v1.k8s.emberstack.com/reflection-allowed: "true"` to the resource annotations to permit reflection to mirrors.
   - Add `reflector.v1.k8s.emberstack.com/reflection-allowed-namespaces: "<list>"` to the resource annotations to permit reflection from only the list of comma separated namespaces or regular expressions. Note: If this annotation is omitted or is empty, all namespaces are allowed.
+  - Add `reflector.v1.k8s.emberstack.com/reflection-labels: "true"` to the resource annotations to permit reflection of labels to mirrors. Note: If this annotation is ommitted or empty no labels are mirrored.
+  - Add `reflector.v1.k8s.emberstack.com/reflection-labels-included: "<list>"` to the resource annotations to permit reflection of only the list of comma separated labels or regular expressions. Note: If this annotation is ommitted or empty all labels are reflected.
 
   #### Automatic mirror creation:
   Reflector can create mirrors with the same name in other namespaces automatically. The following annotations control if and how the mirrors are created:
@@ -110,6 +112,24 @@ $ kubectl -n kube-system apply -f https://github.com/emberstack/kubernetes-refle
   data:
     ...
   ```
+
+  Example source configmap with labels:
+   ```yaml
+  apiVersion: v1
+  kind: ConfigMap
+  metadata:
+    name: source-config-map
+    labels:
+      emberstack.com/included-label: to-be-included
+      example.com/excluded-label: to-be-excluded
+    annotations:
+      reflector.v1.k8s.emberstack.com/reflection-allowed: "true"
+      reflector.v1.k8s.emberstack.com/reflection-allowed-namespaces: "namespace-1,namespace-2,namespace-[0-9]*"
+      reflector.v1.k8s.emberstack.com/reflection-labels: "true"
+      reflector.v1.k8s.emberstack.com/reflection-labels-included: "emberstack\\.com/.*"
+  data:
+    ...
+  ```
 
 ### 2. Annotate the mirror secret or configmap
 

src/ES.Kubernetes.Reflector/Mirroring/Core/Annotations.cs

@@ -1,4 +1,4 @@
-namespace ES.Kubernetes.Reflector.Mirroring.Core;
+namespace ES.Kubernetes.Reflector.Mirroring.Core;
 
 public static class Annotations
 {
@@ -10,6 +10,8 @@ public static class Reflection
         public static string AllowedNamespaces => $"{Prefix}/reflection-allowed-namespaces";
         public static string AutoEnabled => $"{Prefix}/reflection-auto-enabled";
         public static string AutoNamespaces => $"{Prefix}/reflection-auto-namespaces";
+        public static string Labels => $"{Prefix}/reflection-labels";
+        public static string LabelsIncluded => $"{Prefix}/reflection-labels-included";
         public static string Reflects => $"{Prefix}/reflects";
 
 

src/ES.Kubernetes.Reflector/Mirroring/Core/MirroringProperties.cs

@@ -1,4 +1,4 @@
-using System.Diagnostics.CodeAnalysis;
+using System.Diagnostics.CodeAnalysis;
 using ES.FX.KubernetesClient.Models;
 
 namespace ES.Kubernetes.Reflector.Mirroring.Core;
@@ -9,6 +9,8 @@ public class MirroringProperties
     public string AllowedNamespaces { get; set; } = string.Empty;
     public bool AutoEnabled { get; set; }
     public string AutoNamespaces { get; set; } = string.Empty;
+    public bool Labels { get; set; }
+    public string LabelsIncluded { get; set; } = string.Empty;
     public NamespacedName? Reflects { get; set; }
 
     public string ResourceVersion { get; set; } = string.Empty;

src/ES.Kubernetes.Reflector/Mirroring/Core/MirroringPropertiesExtensions.cs

@@ -32,6 +32,14 @@ public static MirroringProperties GetMirroringProperties(this V1ObjectMeta metad
                 ? autoNamespaces ?? string.Empty
                 : string.Empty,
 
+            Labels = metadata
+                .TryGetAnnotationValue(Annotations.Reflection.Labels, out bool labels) && labels,
+
+            LabelsIncluded = metadata
+                .TryGetAnnotationValue(Annotations.Reflection.LabelsIncluded, out string? labelsIncluded)
+                ? labelsIncluded ?? string.Empty
+                : string.Empty,
+
             Reflects = metadata
                 .TryGetAnnotationValue(Annotations.Reflection.Reflects, out string? metaReflects)
                 ? NamespacedName.TryParse(metaReflects, out var id) ? id : null
@@ -63,6 +71,8 @@ public static bool CanBeAutoReflectedToNamespace(this MirroringProperties proper
         properties.CanBeReflectedToNamespace(ns) && properties.AutoEnabled &&
         PatternListMatch(properties.AutoNamespaces, ns);
 
+    public static bool CanLabelBeReflected(this MirroringProperties properties, string label) =>
+        properties.Labels && PatternListMatch(properties.LabelsIncluded, label);
 
     private static bool PatternListMatch(string patternList, string value)
     {

src/ES.Kubernetes.Reflector/Mirroring/Core/ResourceMirror.cs

@@ -459,6 +459,7 @@ private async Task ResourceReflect(NamespacedName sourceNsName, NamespacedName r
             source = sourceObj;
         }
 
+        var sourceProperties = source.GetMirroringProperties();
 
         var patchAnnotations = new Dictionary<string, string>
         {
@@ -487,6 +488,17 @@ private async Task ResourceReflect(NamespacedName sourceNsName, NamespacedName r
                 newResourceAnnotations[Annotations.Reflection.MetaReflectedVersion] = source.Metadata.ResourceVersion;
                 newResourceAnnotations[Annotations.Reflection.MetaReflectedAt] = DateTimeOffset.UtcNow.ToString("O");
 
+                if (sourceProperties.Labels)
+                {
+                    newResource.Metadata.Labels ??= new Dictionary<string, string>();
+                    var newResourceLabels = newResource.Metadata.Labels;
+                    foreach (var label in source.Metadata.Labels)
+                    {
+                        if (sourceProperties.CanLabelBeReflected(label.Key))
+                            newResourceLabels[label.Key] = label.Value;
+                    }
+                }
+
                 try
                 {
                     await OnResourceCreate(newResource, reflectionNsName.Namespace);
@@ -515,6 +527,19 @@ private async Task ResourceReflect(NamespacedName sourceNsName, NamespacedName r
                 annotations[patchAnnotation.Key] = patchAnnotation.Value;
             patchDoc.Replace(e => e.Metadata.Annotations, annotations);
 
+            if (sourceProperties.Labels && source.Metadata.Labels != null)
+            {
+                var labels = new Dictionary<string, string>();
+                if (reflectionObj.Metadata.Labels != null)
+                    labels = new Dictionary<string, string>(reflectionObj.Metadata.Labels);
+                foreach (var label in source.Metadata.Labels)
+                {
+                    if (sourceProperties.CanLabelBeReflected(label.Key))
+                        labels[label.Key] = label.Value;
+                }
+                patchDoc.Replace(e => e.Metadata.Labels, labels);
+            }
+
             await OnResourceConfigurePatch(source, patchDoc);
 
             var patch = JsonConvert.SerializeObject(patchDoc, Formatting.Indented);