From 42db9df386183175e382b3dd2e8241d689fccd27 Mon Sep 17 00:00:00 2001
From: Cameron Moore <moorereason@gmail.com>
Date: Tue, 30 Mar 2021 10:47:34 -0500
Subject: [PATCH] metrics: Add cached count tracking

Fixes #8375
---
 metrics/metrics.go       | 55 +++++++++++++++++++++++++++-------------
 tpl/partials/partials.go |  4 +++
 2 files changed, 42 insertions(+), 17 deletions(-)

diff --git a/metrics/metrics.go b/metrics/metrics.go
index f48ee33e036..7984f1db778 100644
--- a/metrics/metrics.go
+++ b/metrics/metrics.go
@@ -25,11 +25,9 @@ import (
 	"sync"
 	"time"
 
-	"github.com/gohugoio/hugo/helpers"
-
 	"github.com/gohugoio/hugo/common/types"
-
 	"github.com/gohugoio/hugo/compare"
+	"github.com/gohugoio/hugo/helpers"
 )
 
 // The Provider interface defines an interface for measuring metrics.
@@ -44,6 +42,10 @@ type Provider interface {
 	// TrackValue tracks the value for diff calculations etc.
 	TrackValue(key string, value interface{})
 
+	// IncrementCachedExec increments the cached execute count for a given
+	// template.
+	IncrementCachedExec(key string)
+
 	// Reset clears the metric store.
 	Reset()
 }
@@ -54,8 +56,6 @@ type diff struct {
 	simSum   int
 }
 
-var counter = 0
-
 func (d *diff) add(v interface{}) *diff {
 	if types.IsNil(d.baseline) {
 		d.baseline = v
@@ -77,6 +77,8 @@ type Store struct {
 	mu             sync.Mutex
 	diffs          map[string]*diff
 	diffmu         sync.Mutex
+	cached         map[string]int
+	cachedmu       sync.Mutex
 }
 
 // NewProvider returns a new instance of a metric store.
@@ -85,6 +87,7 @@ func NewProvider(calculateHints bool) Provider {
 		calculateHints: calculateHints,
 		metrics:        make(map[string][]time.Duration),
 		diffs:          make(map[string]*diff),
+		cached:         make(map[string]int),
 	}
 }
 
@@ -93,9 +96,31 @@ func (s *Store) Reset() {
 	s.mu.Lock()
 	s.metrics = make(map[string][]time.Duration)
 	s.mu.Unlock()
+
 	s.diffmu.Lock()
 	s.diffs = make(map[string]*diff)
 	s.diffmu.Unlock()
+
+	s.cachedmu.Lock()
+	s.cached = make(map[string]int)
+	s.cachedmu.Unlock()
+}
+
+// IncrementCachedExec increments the cached execute count for a given template.
+func (s *Store) IncrementCachedExec(key string) {
+	if !s.calculateHints {
+		return
+	}
+
+	s.cachedmu.Lock()
+	_, found := s.cached[key]
+
+	if !found {
+		s.cached[key] = 0
+	}
+
+	s.cached[key] += 1
+	s.cachedmu.Unlock()
 }
 
 // TrackValue tracks the value for diff calculations etc.
@@ -105,12 +130,7 @@ func (s *Store) TrackValue(key string, value interface{}) {
 	}
 
 	s.diffmu.Lock()
-	var (
-		d     *diff
-		found bool
-	)
-
-	d, found = s.diffs[key]
+	d, found := s.diffs[key]
 
 	if !found {
 		d = &diff{}
@@ -118,7 +138,6 @@ func (s *Store) TrackValue(key string, value interface{}) {
 	}
 
 	d.add(value)
-
 	s.diffmu.Unlock()
 }
 
@@ -155,17 +174,18 @@ func (s *Store) WriteMetrics(w io.Writer) {
 		}
 
 		avg := time.Duration(int(sum) / len(v))
+		cacheCount := s.cached[k]
 
-		results[i] = result{key: k, count: len(v), max: max, sum: sum, avg: avg, cacheFactor: cacheFactor}
+		results[i] = result{key: k, count: len(v), max: max, sum: sum, avg: avg, cacheCount: cacheCount, cacheFactor: cacheFactor}
 		i++
 	}
 
 	s.mu.Unlock()
 
 	if s.calculateHints {
-		fmt.Fprintf(w, "  %9s  %13s  %12s  %12s  %5s  %s\n", "cache", "cumulative", "average", "maximum", "", "")
-		fmt.Fprintf(w, "  %9s  %13s  %12s  %12s  %5s  %s\n", "potential", "duration", "duration", "duration", "count", "template")
-		fmt.Fprintf(w, "  %9s  %13s  %12s  %12s  %5s  %s\n", "-----", "----------", "--------", "--------", "-----", "--------")
+		fmt.Fprintf(w, "  %9s  %13s  %12s  %12s  %5s  %6s  %s\n", "cache", "cumulative", "average", "maximum", "total", "cached", "")
+		fmt.Fprintf(w, "  %9s  %13s  %12s  %12s  %5s  %6s  %s\n", "potential", "duration", "duration", "duration", "count", "count", "template")
+		fmt.Fprintf(w, "  %9s  %13s  %12s  %12s  %5s  %6s  %s\n", "-----", "----------", "--------", "--------", "-----", "------", "--------")
 	} else {
 		fmt.Fprintf(w, "  %13s  %12s  %12s  %5s  %s\n", "cumulative", "average", "maximum", "", "")
 		fmt.Fprintf(w, "  %13s  %12s  %12s  %5s  %s\n", "duration", "duration", "duration", "count", "template")
@@ -176,7 +196,7 @@ func (s *Store) WriteMetrics(w io.Writer) {
 	sort.Sort(bySum(results))
 	for _, v := range results {
 		if s.calculateHints {
-			fmt.Fprintf(w, "  %9d %13s  %12s  %12s  %5d  %s\n", v.cacheFactor, v.sum, v.avg, v.max, v.count, v.key)
+			fmt.Fprintf(w, "  %9d %13s  %12s  %12s  %5d  %6d   %s\n", v.cacheFactor, v.sum, v.avg, v.max, v.count, v.cacheCount, v.key)
 		} else {
 			fmt.Fprintf(w, "  %13s  %12s  %12s  %5d  %s\n", v.sum, v.avg, v.max, v.count, v.key)
 		}
@@ -187,6 +207,7 @@ func (s *Store) WriteMetrics(w io.Writer) {
 type result struct {
 	key         string
 	count       int
+	cacheCount  int
 	cacheFactor int
 	sum         time.Duration
 	max         time.Duration
diff --git a/tpl/partials/partials.go b/tpl/partials/partials.go
index e8a8adc36d9..e89864b0c08 100644
--- a/tpl/partials/partials.go
+++ b/tpl/partials/partials.go
@@ -225,6 +225,10 @@ func (ns *Namespace) getOrCreate(key partialCacheKey, context interface{}) (resu
 		return nil, err
 	}
 
+	if ns.deps.Metrics != nil {
+		ns.deps.Metrics.IncrementCachedExec("partials/" + key.name)
+	}
+
 	ns.cachedPartials.Lock()
 	defer ns.cachedPartials.Unlock()
 	// Double-check.