http, cache: Track evictions

This commit is contained in:
Martin Polden 2020-09-11 21:55:09 +02:00
parent b7ed233452
commit 832f3655e8
4 changed files with 34 additions and 16 deletions

View File

@ -13,11 +13,13 @@ type Cache struct {
mu sync.RWMutex
entries map[uint64]*list.Element
values *list.List
evictions uint64
}
type CacheStats struct {
Capacity int
Size int
Evictions uint64
}
func NewCache(capacity int) *Cache {
@ -55,6 +57,7 @@ func (c *Cache) Set(ip net.IP, resp Response) {
el = next
evicted++
}
c.evictions += uint64(evicted)
}
current, ok := c.entries[k]
if ok {
@ -81,6 +84,7 @@ func (c *Cache) Resize(capacity int) error {
c.mu.Lock()
defer c.mu.Unlock()
c.capacity = capacity
c.evictions = 0
return nil
}
@ -90,5 +94,6 @@ func (c *Cache) Stats() CacheStats {
return CacheStats{
Size: len(c.entries),
Capacity: c.capacity,
Evictions: c.evictions,
}
}

View File

@ -9,11 +9,13 @@ import (
func TestCacheCapacity(t *testing.T) {
var tests = []struct {
addCount, capacity, size int
evictions uint64
}{
{1, 0, 0},
{1, 2, 1},
{2, 2, 2},
{3, 2, 2},
{1, 0, 0, 0},
{1, 2, 1, 0},
{2, 2, 2, 0},
{3, 2, 2, 1},
{10, 5, 5, 5},
}
for i, tt := range tests {
c := NewCache(tt.capacity)
@ -27,6 +29,9 @@ func TestCacheCapacity(t *testing.T) {
if got := len(c.entries); got != tt.size {
t.Errorf("#%d: len(entries) = %d, want %d", i, got, tt.size)
}
if got := c.evictions; got != tt.evictions {
t.Errorf("#%d: evictions = %d, want %d", i, got, tt.evictions)
}
if tt.capacity > 0 && tt.addCount > tt.capacity && tt.capacity == tt.size {
lastAdded := responses[tt.addCount-1]
if _, ok := c.Get(lastAdded.IP); !ok {
@ -57,7 +62,7 @@ func TestCacheDuplicate(t *testing.T) {
func TestCacheResize(t *testing.T) {
c := NewCache(10)
for i := 1; i <= 10; i++ {
for i := 1; i <= 20; i++ {
ip := net.ParseIP(fmt.Sprintf("192.0.2.%d", i))
r := Response{IP: ip}
c.Set(ip, r)
@ -65,9 +70,15 @@ func TestCacheResize(t *testing.T) {
if got, want := len(c.entries), 10; got != want {
t.Errorf("want %d entries, got %d", want, got)
}
if got, want := c.evictions, uint64(10); got != want {
t.Errorf("want %d evictions, got %d", want, got)
}
if err := c.Resize(5); err != nil {
t.Fatal(err)
}
if got, want := c.evictions, uint64(0); got != want {
t.Errorf("want %d evictions, got %d", want, got)
}
r := Response{IP: net.ParseIP("192.0.2.42")}
c.Set(r.IP, r)
if got, want := len(c.entries), 5; got != want {

View File

@ -301,9 +301,11 @@ func (s *Server) cacheHandler(w http.ResponseWriter, r *http.Request) *appError
var data = struct {
Size int `json:"size"`
Capacity int `json:"capacity"`
Evictions uint64 `json:"evictions"`
}{
cacheStats.Size,
cacheStats.Capacity,
cacheStats.Evictions,
}
b, err := json.Marshal(data)
if err != nil {

View File

@ -187,7 +187,7 @@ func TestCacheHandler(t *testing.T) {
if err != nil {
t.Fatal(err)
}
want := `{"size":0,"capacity":100}`
want := `{"size":0,"capacity":100,"evictions":0}`
if got != want {
t.Errorf("got %q, want %q", got, want)
}