From b214f9cc3a2fc07593baf7f678ab941312e6bcc7 Mon Sep 17 00:00:00 2001
From: Leonor Oliveira <9090754+leonorfmartins@users.noreply.github.com>
Date: Mon, 13 May 2024 10:36:24 +0100
Subject: [PATCH] Add metrics utils to the dualwriter (#87693)

* Add metrics utils

* Ignore lint temporarily

* Lint
---
 pkg/apiserver/rest/dualwriter_mode1.go |  5 ++-
 pkg/apiserver/rest/dualwriter_mode2.go |  5 ++-
 pkg/apiserver/rest/dualwriter_mode3.go |  5 ++-
 pkg/apiserver/rest/dualwriter_mode4.go |  5 ++-
 pkg/apiserver/rest/metrics.go          | 54 ++++++++++++++++++++++++++
 5 files changed, 70 insertions(+), 4 deletions(-)
 create mode 100644 pkg/apiserver/rest/metrics.go

diff --git a/pkg/apiserver/rest/dualwriter_mode1.go b/pkg/apiserver/rest/dualwriter_mode1.go
index 75651998784..6fbb350a95d 100644
--- a/pkg/apiserver/rest/dualwriter_mode1.go
+++ b/pkg/apiserver/rest/dualwriter_mode1.go
@@ -14,12 +14,15 @@ type DualWriterMode1 struct {
 	Legacy  LegacyStorage
 	Storage Storage
 	Log     klog.Logger
+	*dualWriterMetrics
 }
 
 // NewDualWriterMode1 returns a new DualWriter in mode 1.
 // Mode 1 represents writing to and reading from LegacyStorage.
 func NewDualWriterMode1(legacy LegacyStorage, storage Storage) *DualWriterMode1 {
-	return &DualWriterMode1{Legacy: legacy, Storage: storage, Log: klog.NewKlogr().WithName("DualWriterMode1")}
+	metrics := &dualWriterMetrics{}
+	metrics.init()
+	return &DualWriterMode1{Legacy: legacy, Storage: storage, Log: klog.NewKlogr().WithName("DualWriterMode1"), dualWriterMetrics: metrics}
 }
 
 // Create overrides the behavior of the generic DualWriter and writes only to LegacyStorage.
diff --git a/pkg/apiserver/rest/dualwriter_mode2.go b/pkg/apiserver/rest/dualwriter_mode2.go
index 7fa8d2b0199..6be6797ec16 100644
--- a/pkg/apiserver/rest/dualwriter_mode2.go
+++ b/pkg/apiserver/rest/dualwriter_mode2.go
@@ -19,12 +19,15 @@ type DualWriterMode2 struct {
 	Storage Storage
 	Legacy  LegacyStorage
 	Log     klog.Logger
+	*dualWriterMetrics
 }
 
 // NewDualWriterMode2 returns a new DualWriter in mode 2.
 // Mode 2 represents writing to LegacyStorage and Storage and reading from LegacyStorage.
 func NewDualWriterMode2(legacy LegacyStorage, storage Storage) *DualWriterMode2 {
-	return &DualWriterMode2{Legacy: legacy, Storage: storage, Log: klog.NewKlogr().WithName("DualWriterMode2")}
+	metrics := &dualWriterMetrics{}
+	metrics.init()
+	return &DualWriterMode2{Legacy: legacy, Storage: storage, Log: klog.NewKlogr().WithName("DualWriterMode2"), dualWriterMetrics: metrics}
 }
 
 // Create overrides the behavior of the generic DualWriter and writes to LegacyStorage and Storage.
diff --git a/pkg/apiserver/rest/dualwriter_mode3.go b/pkg/apiserver/rest/dualwriter_mode3.go
index 3520d302f52..b0f2630143d 100644
--- a/pkg/apiserver/rest/dualwriter_mode3.go
+++ b/pkg/apiserver/rest/dualwriter_mode3.go
@@ -15,12 +15,15 @@ type DualWriterMode3 struct {
 	Legacy  LegacyStorage
 	Storage Storage
 	Log     klog.Logger
+	*dualWriterMetrics
 }
 
 // NewDualWriterMode3 returns a new DualWriter in mode 3.
 // Mode 3 represents writing to LegacyStorage and Storage and reading from Storage.
 func NewDualWriterMode3(legacy LegacyStorage, storage Storage) *DualWriterMode3 {
-	return &DualWriterMode3{Legacy: legacy, Storage: storage, Log: klog.NewKlogr().WithName("DualWriterMode3")}
+	metrics := &dualWriterMetrics{}
+	metrics.init()
+	return &DualWriterMode3{Legacy: legacy, Storage: storage, Log: klog.NewKlogr().WithName("DualWriterMode3"), dualWriterMetrics: metrics}
 }
 
 // Create overrides the behavior of the generic DualWriter and writes to LegacyStorage and Storage.
diff --git a/pkg/apiserver/rest/dualwriter_mode4.go b/pkg/apiserver/rest/dualwriter_mode4.go
index d562c73f042..ef0847cfcaf 100644
--- a/pkg/apiserver/rest/dualwriter_mode4.go
+++ b/pkg/apiserver/rest/dualwriter_mode4.go
@@ -14,12 +14,15 @@ type DualWriterMode4 struct {
 	Legacy  LegacyStorage
 	Storage Storage
 	Log     klog.Logger
+	*dualWriterMetrics
 }
 
 // NewDualWriterMode4 returns a new DualWriter in mode 4.
 // Mode 4 represents writing and reading from Storage.
 func NewDualWriterMode4(legacy LegacyStorage, storage Storage) *DualWriterMode4 {
-	return &DualWriterMode4{Legacy: legacy, Storage: storage, Log: klog.NewKlogr().WithName("DualWriterMode4")}
+	metrics := &dualWriterMetrics{}
+	metrics.init()
+	return &DualWriterMode4{Legacy: legacy, Storage: storage, Log: klog.NewKlogr().WithName("DualWriterMode4"), dualWriterMetrics: metrics}
 }
 
 // #TODO remove all DualWriterMode4 methods once we remove the generic DualWriter implementation
diff --git a/pkg/apiserver/rest/metrics.go b/pkg/apiserver/rest/metrics.go
new file mode 100644
index 00000000000..36706efeec7
--- /dev/null
+++ b/pkg/apiserver/rest/metrics.go
@@ -0,0 +1,54 @@
+package rest
+
+import "github.com/prometheus/client_golang/prometheus"
+
+type dualWriterMetrics struct {
+	legacy  *prometheus.HistogramVec
+	storage *prometheus.HistogramVec
+	outcome *prometheus.HistogramVec
+}
+
+// DualWriterStorageDuration is a metric summary for dual writer storage duration per mode
+var DualWriterStorageDuration = prometheus.NewHistogramVec(prometheus.HistogramOpts{
+	Name:                        "dual_writer_storage_duration_seconds",
+	Help:                        "Histogram for the runtime of dual writer storage duration per mode",
+	Namespace:                   "grafana",
+	NativeHistogramBucketFactor: 1.1,
+}, []string{"status_code", "mode", "name", "method"})
+
+// DualWriterLegacyDuration is a metric summary for dual writer legacy duration per mode
+var DualWriterLegacyDuration = prometheus.NewHistogramVec(prometheus.HistogramOpts{
+	Name:                        "dual_writer_legacy_duration_seconds",
+	Help:                        "Histogram for the runtime of dual writer legacy duration per mode",
+	Namespace:                   "grafana",
+	NativeHistogramBucketFactor: 1.1,
+}, []string{"status_code", "mode", "name", "method"})
+
+// DualWriterOutcome is a metric summary for dual writer outcome comparison between the 2 stores per mode
+var DualWriterOutcome = prometheus.NewHistogramVec(prometheus.HistogramOpts{
+	Name:                        "dual_writer_outcome",
+	Help:                        "Histogram for the runtime of dual writer outcome comparison between the 2 stores per mode",
+	Namespace:                   "grafana",
+	NativeHistogramBucketFactor: 1.1,
+}, []string{"mode", "name", "outcome", "method"})
+
+func (m *dualWriterMetrics) init() {
+	m.legacy = DualWriterLegacyDuration
+	m.storage = DualWriterStorageDuration
+	m.outcome = DualWriterOutcome
+}
+
+// nolint:unused
+func (m *dualWriterMetrics) recordLegacyDuration(statusCode string, mode string, name string, method string, duration float64) {
+	m.legacy.WithLabelValues(statusCode, mode, name, method).Observe(duration)
+}
+
+// nolint:unused
+func (m *dualWriterMetrics) recordStorageDuration(statusCode string, mode string, name string, method string, duration float64) {
+	m.storage.WithLabelValues(statusCode, mode, name, method).Observe(duration)
+}
+
+// nolint:unused
+func (m *dualWriterMetrics) recordOutcome(mode string, name string, outcome string, method string) {
+	m.outcome.WithLabelValues(mode, name, outcome, method).Observe(1)
+}