maxitem config for mapblock cache

server/app/config.go

@@ -27,6 +27,7 @@ type Config struct {
 type MapBlockAccessorConfig struct {
 	Expiretime string `json:"expiretime"`
 	Purgetime  string `json:"purgetime"`
+	MaxItems   int    `json:"maxitems"`
 }
 
 type MapObjectConfig struct {
@@ -128,8 +129,9 @@ func ParseConfig(filename string) (*Config, error) {
 	}
 
 	mapblockaccessor := MapBlockAccessorConfig{
-		Expiretime: "500ms",
-		Purgetime:  "1000ms",
+		Expiretime: "15s",
+		Purgetime:  "30s",
+		MaxItems:   5000,
 	}
 
 	cfg := Config{

server/app/setup.go

@@ -69,7 +69,10 @@ func Setup(p params.ParamsType, cfg *Config) *App {
 		panic(err)
 	}
 
-	a.BlockAccessor = mapblockaccessor.NewMapBlockAccessor(a.Blockdb, expireDuration, purgeDuration)
+	a.BlockAccessor = mapblockaccessor.NewMapBlockAccessor(
+		a.Blockdb,
+		expireDuration, purgeDuration,
+		cfg.MapBlockAccessorCfg.MaxItems)
 
 	//color mapping
 	a.Colormapping = colormapping.NewColorMapping()

server/mapblockaccessor/get.go

@@ -7,11 +7,23 @@ import (
 
 	cache "github.com/patrickmn/go-cache"
 	"github.com/prometheus/client_golang/prometheus"
+	"github.com/sirupsen/logrus"
 )
 
 func (a *MapBlockAccessor) GetMapBlock(pos *coords.MapBlockCoords) (*mapblockparser.MapBlock, error) {
 	key := getKey(pos)
 
+	if a.c.ItemCount() > a.maxcount {
+		//flush cache
+		fields := logrus.Fields{
+			"cached items": a.c.ItemCount(),
+			"maxcount":     a.maxcount,
+		}
+		logrus.WithFields(fields).Warn("Flushing cache")
+
+		a.c.Flush()
+	}
+
 	cachedblock, found := a.c.Get(key)
 	if found {
 		getCacheHitCount.Inc()

server/mapblockaccessor/mapblockaccessor.go

@@ -15,18 +15,20 @@ type MapBlockAccessor struct {
 	accessor db.DBAccessor
 	c        *cache.Cache
 	Eventbus *eventbus.Eventbus
+	maxcount int
 }
 
 func getKey(pos *coords.MapBlockCoords) string {
 	return fmt.Sprintf("Coord %d/%d/%d", pos.X, pos.Y, pos.Z)
 }
 
-func NewMapBlockAccessor(accessor db.DBAccessor, expiretime, purgetime time.Duration) *MapBlockAccessor {
+func NewMapBlockAccessor(accessor db.DBAccessor, expiretime, purgetime time.Duration, maxcount int) *MapBlockAccessor {
 	c := cache.New(expiretime, purgetime)
 
 	return &MapBlockAccessor{
 		accessor: accessor,
 		c:        c,
 		Eventbus: eventbus.New(),
+		maxcount: maxcount,
 	}
 }

server/mapblockaccessor/mapblockaccessor_test.go

@@ -32,7 +32,7 @@ func TestSimpleAccess(t *testing.T) {
 		panic(err)
 	}
 
-	cache := NewMapBlockAccessor(a, 500*time.Millisecond, 1000*time.Millisecond)
+	cache := NewMapBlockAccessor(a, 500*time.Millisecond, 1000*time.Millisecond, 1000)
 	mb, err := cache.GetMapBlock(coords.NewMapBlockCoords(0, 0, 0))
 
 	if err != nil {