feat: Add kube_deployment_spec_topology_spread_constraints metric for issue #2701

docs/metrics/workload/deployment-metrics.md

@@ -14,6 +14,7 @@
 | kube_deployment_spec_paused                                 | Gauge       | Whether the deployment is paused and will not be processed by the deployment controller.                                               | `deployment`=&lt;deployment-name&gt; <br> `namespace`=&lt;deployment-namespace&gt;                                                                                          | STABLE       |
 | kube_deployment_spec_strategy_rollingupdate_max_unavailable | Gauge       | Maximum number of unavailable replicas during a rolling update of a deployment.                                                        | `deployment`=&lt;deployment-name&gt; <br> `namespace`=&lt;deployment-namespace&gt;                                                                                          | STABLE       |
 | kube_deployment_spec_strategy_rollingupdate_max_surge       | Gauge       | Maximum number of replicas that can be scheduled above the desired number of replicas during a rolling update of a deployment.        | `deployment`=&lt;deployment-name&gt; <br> `namespace`=&lt;deployment-namespace&gt;                                                                                          | STABLE       |
+| kube_deployment_spec_topology_spread_constraint             | Gauge       | Explicit details of each topology spread constraint in the deployment's pod template                                                    | `deployment`=&lt;deployment-name&gt; <br> `namespace`=&lt;deployment-namespace&gt; <br> `topology_key`=&lt;topology-key&gt; <br> `max_skew`=&lt;max-skew-value&gt; <br> `when_unsatisfiable`=&lt;DoNotSchedule\|ScheduleAnyway&gt; <br> `min_domains`=&lt;min-domains-value&gt; <br> `label_selector`=&lt;label-selector-string&gt; | ALPHA        |
 | kube_deployment_metadata_generation                         | Gauge       | Sequence number representing a specific generation of the desired state.                                                               | `deployment`=&lt;deployment-name&gt; <br> `namespace`=&lt;deployment-namespace&gt;                                                                                          | STABLE       |
 | kube_deployment_labels                                      | Gauge       | Kubernetes labels converted to Prometheus labels controlled via [--metric-labels-allowlist](../../developer/cli-arguments.md)           | `deployment`=&lt;deployment-name&gt; <br> `namespace`=&lt;deployment-namespace&gt; <br> `label_DEPLOYMENT_LABEL`=&lt;DEPLOYMENT_LABEL&gt;                                   | STABLE       |
 | kube_deployment_created                                     | Gauge       | Unix creation timestamp                                                                                                                 | `deployment`=&lt;deployment-name&gt; <br> `namespace`=&lt;deployment-namespace&gt;                                                                                          | STABLE       |

examples/autosharding/cluster-role.yaml

@@ -125,4 +125,4 @@ rules:
   - roles
   verbs:
   - list
-  - watch
+  - watch

examples/autosharding/role-binding.yaml

@@ -12,5 +12,5 @@ roleRef:
   kind: Role
   name: kube-state-metrics
 subjects:
-- kind: ServiceAccount
-  name: kube-state-metrics
+  - kind: ServiceAccount
+    name: kube-state-metrics

examples/autosharding/role.yaml

@@ -21,4 +21,4 @@ rules:
   resources:
   - statefulsets
   verbs:
-  - get
+  - get  

examples/autosharding/service.yaml

@@ -15,6 +15,6 @@ spec:
     targetPort: http-metrics
   - name: telemetry
     port: 8081
-    targetPort: telemetry
+    targetPort: telemetry 
   selector:
     app.kubernetes.io/name: kube-state-metrics

examples/standard/cluster-role.yaml

@@ -125,4 +125,4 @@ rules:
   - roles
   verbs:
   - list
-  - watch
+  - watch  

examples/standard/service.yaml

@@ -15,6 +15,6 @@ spec:
     targetPort: http-metrics
   - name: telemetry
     port: 8081
-    targetPort: telemetry
+    targetPort: telemetry 
   selector:
     app.kubernetes.io/name: kube-state-metrics

internal/store/deployment.go

@@ -18,6 +18,7 @@ package store
 
 import (
 	"context"
+	"strconv"
 
 	basemetrics "k8s.io/component-base/metrics"
 
@@ -289,6 +290,42 @@ func deploymentMetricFamilies(allowAnnotationsList, allowLabelsList []string) []
 				}
 			}),
 		),
+		*generator.NewFamilyGeneratorWithStability(
+			"kube_deployment_spec_topology_spread_constraint",
+			"Explicit details of each topology spread constraint in the deployment's pod template.",
+			metric.Gauge,
+			basemetrics.ALPHA,
+			"",
+			wrapDeploymentFunc(func(d *v1.Deployment) *metric.Family {
+				ms := []*metric.Metric{}
+				for _, constraint := range d.Spec.Template.Spec.TopologySpreadConstraints {
+					labelSelectorStr, err := metav1.LabelSelectorAsSelector(constraint.LabelSelector)
+					if err != nil {
+						// Skip invalid label selectors
+						continue
+					}
+
+					minDomainsStr := "1" // default value when nil
+					if constraint.MinDomains != nil {
+						minDomainsStr = strconv.Itoa(int(*constraint.MinDomains))
+					}
+
+					ms = append(ms, &metric.Metric{
+						LabelKeys: []string{"topology_key", "max_skew", "when_unsatisfiable", "min_domains", "label_selector"},
+						LabelValues: []string{
+							constraint.TopologyKey,
+							strconv.Itoa(int(constraint.MaxSkew)),
+							string(constraint.WhenUnsatisfiable),
+							minDomainsStr,
+							labelSelectorStr.String(),
+						},
+						Value: 1,
+					})
+				}
+				return &metric.Family{Metrics: ms}
+			}),
+		),
+
 		*generator.NewFamilyGeneratorWithStability(
 			"kube_deployment_metadata_generation",
 			"Sequence number representing a specific generation of the desired state.",