add some comments

cluster/router/healthcheck/default_health_check.go

@@ -37,11 +37,11 @@ func init() {
 // DefaultHealthChecker is the default implementation of HealthChecker, which determines the health status of
 // the invoker based on the number of successive bad request and the current active request.
 type DefaultHealthChecker struct {
-	// outStandingRequestConutLimit
+	// the limit of outstanding request
 	outStandingRequestConutLimit int32
-	// requestSuccessiveFailureThreshold
+	// the threshold of successive-failure-request
 	requestSuccessiveFailureThreshold int32
-	// requestSuccessiveFailureThreshold
+	// value of circuit-tripped timeout factor
 	circuitTrippedTimeoutFactor int32
 }
 

cluster/router/healthcheck/health_check_route.go

@@ -39,9 +39,10 @@ type HealthCheckRouter struct {
 
 // NewHealthCheckRouter construct an HealthCheckRouter via url
 func NewHealthCheckRouter(url *common.URL) (router.Router, error) {
-	r := &HealthCheckRouter{}
-	r.url = url
-	r.enabled = url.GetParamBool(HEALTH_ROUTE_ENABLED_KEY, false)
+	r := &HealthCheckRouter{
+		url:     url,
+		enabled: url.GetParamBool(HEALTH_ROUTE_ENABLED_KEY, false),
+	}
 	if r.enabled {
 		checkerName := url.GetParam(constant.HEALTH_CHECKER, constant.DEFAULT_HEALTH_CHECKER)
 		r.checker = extension.GetHealthChecker(checkerName, url)
@@ -54,7 +55,7 @@ func (r *HealthCheckRouter) Route(invokers []protocol.Invoker, url *common.URL,
 	if !r.enabled {
 		return invokers
 	}
-	var healthyInvokers []protocol.Invoker
+	healthyInvokers := make([]protocol.Invoker, 0, len(invokers))
 	// Add healthy invoker to the list
 	for _, invoker := range invokers {
 		if r.checker.IsHealthy(invoker) {
@@ -65,9 +66,8 @@ func (r *HealthCheckRouter) Route(invokers []protocol.Invoker, url *common.URL,
 	if len(healthyInvokers) == 0 {
 		logger.Warnf(" Now all invokers are unhealthy, so downgraded to all! Service: [%s]", url.ServiceKey())
 		return invokers
-	} else {
-		return healthyInvokers
 	}
+	return healthyInvokers
 }
 
 // Priority

common/constant/key.go

@@ -193,13 +193,22 @@ const (
 
 // HealthCheck Router
 const (
-	HEALTH_CHECKER                             = "health.checker"
-	DEFAULT_HEALTH_CHECKER                     = "default"
-	OUTSTANDING_REQUEST_COUNT_LIMIT_KEY        = "outstanding.request.limit"
-	SUCCESSIVE_FAILED_REQUEST_THRESHOLD_KEY    = "successive.failed.threshold"
-	DEFAULT_SUCCESSIVE_FAILED_THRESHOLD        = 5
-	CIRCUIT_TRIPPED_TIMEOUT_FACTOR_KEY         = "circuit.tripped.timeout.factor"
+	// The key of HealthCheck SPI
+	HEALTH_CHECKER = "health.checker"
+	// The name of the default implementation of HealthChecker
+	DEFAULT_HEALTH_CHECKER = "default"
+	// The key of oustanding-request-limit
+	OUTSTANDING_REQUEST_COUNT_LIMIT_KEY = "outstanding.request.limit"
+	// The key of successive-failed-request's threshold
+	SUCCESSIVE_FAILED_REQUEST_THRESHOLD_KEY = "successive.failed.threshold"
+	// The key of circuit-tripped timeout factor
+	CIRCUIT_TRIPPED_TIMEOUT_FACTOR_KEY = "circuit.tripped.timeout.factor"
+	// The default threshold of  successive-failed-request if not specfied
+	DEFAULT_SUCCESSIVE_FAILED_THRESHOLD = 5
+	// The default maximum diff between successive-failed-request's threshold and actual successive-failed-request's count
 	DEFAULT_SUCCESSIVE_FAILED_REQUEST_MAX_DIFF = 5
-	DEFAULT_CIRCUIT_TRIPPED_TIMEOUT_FACTOR     = 1000
-	MAX_CIRCUIT_TRIPPED_TIMEOUT_IN_MS          = 30000
+	// The default factor of  circuit-tripped timeout if not specfied
+	DEFAULT_CIRCUIT_TRIPPED_TIMEOUT_FACTOR = 1000
+	// The default time window of circuit-tripped  in millisecond if not specfied
+	MAX_CIRCUIT_TRIPPED_TIMEOUT_IN_MS = 30000
 )