From 7c77d160c4e7459b144259470d1c5a1e37022394 Mon Sep 17 00:00:00 2001
From: Manohar HT <manohar.ht@vimeo.com>
Date: Mon, 6 Feb 2023 11:50:57 +0530
Subject: [PATCH] latency distribution for local gets with GetterFunc

---
 galaxycache.go   | 4 ++++
 observability.go | 4 ++++
 2 files changed, 8 insertions(+)

diff --git a/galaxycache.go b/galaxycache.go
index ca89c913..19918ba0 100644
--- a/galaxycache.go
+++ b/galaxycache.go
@@ -613,6 +613,10 @@ func (g *Galaxy) load(ctx context.Context, key string, dest Codec) (value valWit
 }
 
 func (g *Galaxy) getLocally(ctx context.Context, key string, dest Codec) ([]byte, error) {
+	startTime := time.Now()
+	defer func() {
+		stats.RecordWithTags(ctx, nil, MGetterFuncLatencyMilliseconds.M(sinceInMilliseconds(startTime)))
+	}()
 	err := g.getter.Get(ctx, key, dest)
 	if err != nil {
 		return nil, err
diff --git a/observability.go b/observability.go
index c1aa2522..467d9a18 100644
--- a/observability.go
+++ b/observability.go
@@ -55,6 +55,8 @@ var (
 
 	MCacheSize    = stats.Int64("galaxycache/cache_bytes", "The number of bytes used for storing Keys and Values in the cache", stats.UnitBytes)
 	MCacheEntries = stats.Int64("galaxycache/cache_entries", "The number of entries in the cache", stats.UnitDimensionless)
+
+	MGetterFuncLatencyMilliseconds = stats.Float64("galaxycache/getterfunc_latency", "Local getter function latency in milliseconds", stats.UnitMilliseconds)
 )
 
 var (
@@ -90,6 +92,8 @@ var AllViews = []*view.View{
 	{Measure: MRoundtripLatencyMilliseconds, TagKeys: []tag.Key{GalaxyKey}, Aggregation: defaultMillisecondsDistribution},
 	{Measure: MCacheSize, TagKeys: []tag.Key{GalaxyKey, CacheTypeKey}, Aggregation: view.LastValue()},
 	{Measure: MCacheEntries, TagKeys: []tag.Key{GalaxyKey, CacheTypeKey}, Aggregation: view.LastValue()},
+
+	{Measure: MGetterFuncLatencyMilliseconds, TagKeys: []tag.Key{GalaxyKey}, Aggregation: defaultMillisecondsDistribution},
 }
 
 func sinceInMilliseconds(start time.Time) float64 {