refactor: clean up code (#5308)

pkg/util/metric/date_counter.go

@@ -17,6 +17,8 @@ package metric
 import (
 	"sync"
 	"time"
+
+	"k8s.io/utils/clock"
 )
 
 type DateCounter interface {
@@ -38,27 +40,33 @@ func NewDateCounter(reserveDays int64) DateCounter {
 type StandardDateCounter struct {
 	reserveDays int64
 	counts      []int64
+	clock       clock.PassiveClock
 
 	lastUpdateDate time.Time
 	mu             sync.Mutex
 }
 
 func newStandardDateCounter(reserveDays int64) *StandardDateCounter {
-	now := time.Now()
-	now = time.Date(now.Year(), now.Month(), now.Day(), 0, 0, 0, 0, now.Location())
-	s := &StandardDateCounter{
+	return newStandardDateCounterWithClock(reserveDays, clock.RealClock{})
+}
+
+func newStandardDateCounterWithClock(reserveDays int64, clk clock.PassiveClock) *StandardDateCounter {
+	if clk == nil {
+		clk = clock.RealClock{}
+	}
+	return &StandardDateCounter{
 		reserveDays:    reserveDays,
 		counts:         make([]int64, reserveDays),
-		lastUpdateDate: now,
+		clock:          clk,
+		lastUpdateDate: startOfDay(clk.Now()),
 	}
-	return s
 }
 
 func (c *StandardDateCounter) TodayCount() int64 {
 	c.mu.Lock()
 	defer c.mu.Unlock()
 
-	c.rotate(time.Now())
+	c.rotate(c.clock.Now())
 	return c.counts[0]
 }
 
@@ -70,65 +78,61 @@ func (c *StandardDateCounter) GetLastDaysCount(lastdays int64) []int64 {
 
 	c.mu.Lock()
 	defer c.mu.Unlock()
-	c.rotate(time.Now())
-	for i := 0; i < int(lastdays); i++ {
-		counts[i] = c.counts[i]
-	}
+	c.rotate(c.clock.Now())
+	copy(counts, c.counts)
 	return counts
 }
 
 func (c *StandardDateCounter) Inc(count int64) {
 	c.mu.Lock()
 	defer c.mu.Unlock()
-	c.rotate(time.Now())
+	c.rotate(c.clock.Now())
 	c.counts[0] += count
 }
 
 func (c *StandardDateCounter) Dec(count int64) {
 	c.mu.Lock()
 	defer c.mu.Unlock()
-	c.rotate(time.Now())
+	c.rotate(c.clock.Now())
 	c.counts[0] -= count
 }
 
 func (c *StandardDateCounter) Snapshot() DateCounter {
 	c.mu.Lock()
 	defer c.mu.Unlock()
-	tmp := newStandardDateCounter(c.reserveDays)
-	for i := 0; i < int(c.reserveDays); i++ {
-		tmp.counts[i] = c.counts[i]
-	}
+	tmp := newStandardDateCounterWithClock(c.reserveDays, c.clock)
+	copy(tmp.counts, c.counts)
 	return tmp
 }
 
 func (c *StandardDateCounter) Clear() {
 	c.mu.Lock()
 	defer c.mu.Unlock()
-	for i := 0; i < int(c.reserveDays); i++ {
-		c.counts[i] = 0
-	}
+	clear(c.counts)
 }
 
 // rotate
 // Must hold the lock before calling this function.
 func (c *StandardDateCounter) rotate(now time.Time) {
-	now = time.Date(now.Year(), now.Month(), now.Day(), 0, 0, 0, 0, now.Location())
+	now = startOfDay(now)
 	days := int(now.Sub(c.lastUpdateDate).Hours() / 24)
-
-	defer func() {
-		c.lastUpdateDate = now
-	}()
+	reserveDays := int(c.reserveDays)
 
 	if days <= 0 {
 		return
-	} else if days >= int(c.reserveDays) {
+	} else if days >= reserveDays {
 		c.counts = make([]int64, c.reserveDays)
+		c.lastUpdateDate = now
 		return
 	}
 	newCounts := make([]int64, c.reserveDays)
 
-	for i := days; i < int(c.reserveDays); i++ {
-		newCounts[i] = c.counts[i-days]
-	}
+	copy(newCounts[days:], c.counts[:reserveDays-days])
 	c.counts = newCounts
+	c.lastUpdateDate = now
+}
+
+// startOfDay returns midnight in t's location.
+func startOfDay(t time.Time) time.Time {
+	return time.Date(t.Year(), t.Month(), t.Day(), 0, 0, 0, 0, t.Location())
 }

pkg/util/metric/date_counter_test.go

@@ -1,9 +1,12 @@
 package metric
 
 import (
+	"sync"
 	"testing"
+	"time"
 
 	"github.com/stretchr/testify/require"
+	clocktesting "k8s.io/utils/clock/testing"
 )
 
 func TestDateCounter(t *testing.T) {
@@ -25,3 +28,107 @@ func TestDateCounter(t *testing.T) {
 	dcTmp := dc.Snapshot()
 	require.EqualValues(5, dcTmp.TodayCount())
 }
+
+func TestDateCounterRotate(t *testing.T) {
+	loc := time.FixedZone("test", 8*60*60)
+	lastUpdateDate := time.Date(2026, time.May, 8, 0, 0, 0, 0, loc)
+
+	tests := []struct {
+		name               string
+		now                time.Time
+		want               []int64
+		wantLastUpdateDate time.Time
+	}{
+		{
+			name:               "same day",
+			now:                time.Date(2026, time.May, 8, 12, 30, 0, 0, loc),
+			want:               []int64{10, 7, 3},
+			wantLastUpdateDate: lastUpdateDate,
+		},
+		{
+			name:               "clock skew",
+			now:                time.Date(2026, time.May, 7, 12, 30, 0, 0, loc),
+			want:               []int64{10, 7, 3},
+			wantLastUpdateDate: lastUpdateDate,
+		},
+		{
+			name:               "one day",
+			now:                time.Date(2026, time.May, 9, 12, 30, 0, 0, loc),
+			want:               []int64{0, 10, 7},
+			wantLastUpdateDate: time.Date(2026, time.May, 9, 0, 0, 0, 0, loc),
+		},
+		{
+			name:               "two days",
+			now:                time.Date(2026, time.May, 10, 12, 30, 0, 0, loc),
+			want:               []int64{0, 0, 10},
+			wantLastUpdateDate: time.Date(2026, time.May, 10, 0, 0, 0, 0, loc),
+		},
+		{
+			name:               "all reserved days elapsed",
+			now:                time.Date(2026, time.May, 11, 12, 30, 0, 0, loc),
+			want:               []int64{0, 0, 0},
+			wantLastUpdateDate: time.Date(2026, time.May, 11, 0, 0, 0, 0, loc),
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			require := require.New(t)
+
+			dc := newStandardDateCounter(3)
+			dc.counts = []int64{10, 7, 3}
+			dc.lastUpdateDate = lastUpdateDate
+
+			dc.mu.Lock()
+			dc.rotate(tt.now)
+			dc.mu.Unlock()
+
+			require.Equal(tt.want, dc.counts)
+			require.Equal(tt.wantLastUpdateDate, dc.lastUpdateDate)
+		})
+	}
+}
+
+func TestDateCounterGetLastDaysCountReturnsCopy(t *testing.T) {
+	require := require.New(t)
+
+	clk := clocktesting.NewFakeClock(time.Date(2026, time.May, 8, 12, 30, 0, 0, time.Local))
+	dc := newStandardDateCounterWithClock(3, clk)
+	dc.counts = []int64{10, 7, 3}
+
+	counts := dc.GetLastDaysCount(2)
+	require.Equal([]int64{10, 7}, counts)
+
+	counts[0] = 100
+	require.Equal([]int64{10, 7}, dc.GetLastDaysCount(2))
+}
+
+func TestDateCounterClear(t *testing.T) {
+	require := require.New(t)
+
+	dc := newStandardDateCounter(3)
+	dc.counts = []int64{10, 7, 3}
+
+	dc.Clear()
+
+	require.Equal([]int64{0, 0, 0}, dc.counts)
+}
+
+func TestDateCounterConcurrentAccess(t *testing.T) {
+	clk := clocktesting.NewFakeClock(time.Date(2026, time.May, 8, 12, 30, 0, 0, time.Local))
+	dc := newStandardDateCounterWithClock(3, clk)
+
+	var wg sync.WaitGroup
+	for range 8 {
+		wg.Go(func() {
+			for range 100 {
+				dc.Inc(1)
+				dc.Dec(1)
+				_ = dc.TodayCount()
+				_ = dc.GetLastDaysCount(3)
+				_ = dc.Snapshot()
+			}
+		})
+	}
+	wg.Wait()
+}