chore: set 1000 as default max limit (#4315)

router/throttler/adaptive.go

@@ -16,6 +16,8 @@ type adaptiveThrottleConfig struct {
 	maxLimit func() int64
 }
 
+const adaptiveDefaultMaxLimit = 1000 // 1000 requests per second
+
 func (c *adaptiveThrottleConfig) readThrottlingConfig(config *config.Config, destName, destID string) {
 	c.window = config.GetReloadableDurationVar(1, time.Second,
 		fmt.Sprintf(`Router.throttler.%s.%s.timeWindow`, destName, destID),
@@ -36,12 +38,17 @@ func (c *adaptiveThrottleConfig) readThrottlingConfig(config *config.Config, des
 	limit := config.GetReloadableInt64Var(0, 1,
 		fmt.Sprintf(`Router.throttler.%s.%s.limit`, destName, destID),
 		fmt.Sprintf(`Router.throttler.%s.limit`, destName))
+	defaultMaxLimit := config.GetReloadableInt64Var(adaptiveDefaultMaxLimit, 1, `Router.throttler.adaptive.defaultMaxLimit`)
 	c.maxLimit = func() int64 {
 		maxLimit := maxLimit.Load()
+		staticLimit := limit.Load()
+		staticLimitMultiplier := limitMultiplier.Load()
 		if maxLimit > 0 {
 			return maxLimit
+		} else if staticLimit > 0 && staticLimitMultiplier > 0 {
+			return int64(float64(staticLimit) * staticLimitMultiplier)
 		}
-		return int64(float64(limit.Load()) * limitMultiplier.Load())
+		return defaultMaxLimit.Load()
 	}
 }
 

router/throttler/factory_test.go

@@ -103,6 +103,16 @@ func TestFactory(t *testing.T) {
 			"destType":      "destName",
 		}).LastValue())
 	})
+
+	t.Run("when no limit is set", func(t *testing.T) {
+		conf := config.New()
+		conf.Set("Router.throttler.adaptive.enabled", true)
+		f, err := NewFactory(conf, nil)
+		require.NoError(t, err)
+		defer f.Shutdown()
+		ta := f.Get("destName", "destID")
+		require.EqualValues(t, adaptiveDefaultMaxLimit, ta.getLimit())
+	})
 }
 
 func floatCheck(a, b int64) bool {