From 7c825c45bc35effcc381cbc2545df2418f8e5189 Mon Sep 17 00:00:00 2001
From: Eric Ernst <eric_ernst@apple.com>
Date: Fri, 23 Oct 2020 11:57:26 -0700
Subject: [PATCH] pod: add gauge for runtimeclass handler

Add a metric gauge to provide observability for the runtimeclass
used for running a pod.

Signed-off-by: Eric Ernst <eric_ernst@apple.com>
---
 docs/pod-metrics.md        |  1 +
 internal/store/pod.go      | 21 +++++++++++++++++++++
 internal/store/pod_test.go |  2 +-
 main_test.go               |  2 ++
 4 files changed, 25 insertions(+), 1 deletion(-)

diff --git a/docs/pod-metrics.md b/docs/pod-metrics.md
index 1127e381de..3f28a09c5a 100644
--- a/docs/pod-metrics.md
+++ b/docs/pod-metrics.md
@@ -32,6 +32,7 @@
 | kube_pod_container_resource_limits_ephemeral_storage_bytes | Gauge | `container`=&lt;container-name&gt; <br> `pod`=&lt;pod-name&gt; <br> `namespace`=&lt;pod-namespace&gt; | EXPERIMENTAL |
 | kube_pod_overhead_cpu_cores | Gauge | `pod`=&lt;pod-name&gt; <br> `namespace`=&lt;pod-namespace&gt; | EXPERIMENTAL |
 | kube_pod_overhead_memory_bytes | Gauge | `pod`=&lt;pod-name&gt; <br> `namespace`=&lt;pod-namespace&gt; | EXPERIMENTAL |
+| kube_pod_runtimeclass_handler | Gauge | `pod`=&lt;pod-name&gt; <br> `namespace`=&lt;pod-namespace&gt; | EXPERIMENTAL |
 | kube_pod_created | Gauge | `pod`=&lt;pod-name&gt; <br> `namespace`=&lt;pod-namespace&gt; | STABLE |
 | kube_pod_deletion_timestamp | Gauge | `pod`=&lt;pod-name&gt; <br> `namespace`=&lt;pod-namespace&gt; | EXPERIMENTAL |
 | kube_pod_restart_policy | Gauge | `pod`=&lt;pod-name&gt; <br> `namespace`=&lt;pod-namespace&gt; <br> `type`=&lt;Always|Never|OnFailure&gt; | STABLE |
diff --git a/internal/store/pod.go b/internal/store/pod.go
index 0a0a744d12..639e94bdcb 100644
--- a/internal/store/pod.go
+++ b/internal/store/pod.go
@@ -1511,6 +1511,27 @@ var (
 					}
 				}
 
+				return &metric.Family{
+					Metrics: ms,
+				}
+			}),
+		),
+		*generator.NewFamilyGenerator(
+			"kube_pod_runtimeclass_handler",
+			"The runtimeclass handler associated with the pod.",
+			metric.Gauge,
+			"",
+			wrapPodFunc(func(p *v1.Pod) *metric.Family {
+				ms := []*metric.Metric{}
+
+				if p.Spec.RuntimeClassName != nil {
+					ms = append(ms, &metric.Metric{
+						LabelKeys:   []string{"runtimeclass_handler"},
+						LabelValues: []string{*p.Spec.RuntimeClassName},
+						Value:       1,
+					})
+				}
+
 				return &metric.Family{
 					Metrics: ms,
 				}
diff --git a/internal/store/pod_test.go b/internal/store/pod_test.go
index 1b7d2183f6..c1b5eeb499 100644
--- a/internal/store/pod_test.go
+++ b/internal/store/pod_test.go
@@ -1695,7 +1695,7 @@ func BenchmarkPodStore(b *testing.B) {
 		},
 	}
 
-	expectedFamilies := 57
+	expectedFamilies := 58
 	for n := 0; n < b.N; n++ {
 		families := f(pod)
 		if len(families) != expectedFamilies {
diff --git a/main_test.go b/main_test.go
index 719bd7ad0d..764ab48bea 100644
--- a/main_test.go
+++ b/main_test.go
@@ -354,6 +354,8 @@ kube_pod_container_resource_limits{namespace="default",pod="pod0",container="pod
 # TYPE kube_pod_overhead_cpu_cores gauge
 # HELP kube_pod_overhead_memory_bytes The pod overhead in regards to memory associated with running a pod.
 # TYPE kube_pod_overhead_memory_bytes gauge
+# HELP kube_pod_runtimeclass_handler The runtimeclass handler associated with the pod.
+# TYPE kube_pod_runtimeclass_handler gauge
 `
 
 	expectedSplit := strings.Split(strings.TrimSpace(expected), "\n")