From 98800767e0365418ebb154737bdaf7be06a7d0ce Mon Sep 17 00:00:00 2001
From: ale <ale@incal.net>
Date: Tue, 13 Jan 2015 10:33:28 +0000
Subject: [PATCH] prevent division by 0 in utilization scorer
---
fe/lbv2/lbv2.go | 8 +++++++-
fe/loadbalancing_test.go | 18 ++++++++++++++++++
2 files changed, 25 insertions(+), 1 deletion(-)
diff --git a/fe/lbv2/lbv2.go b/fe/lbv2/lbv2.go
index dac92092..031edb03 100644
--- a/fe/lbv2/lbv2.go
+++ b/fe/lbv2/lbv2.go
@@ -293,7 +293,13 @@ type capacityAvailableScorer struct {
}
func (s *capacityAvailableScorer) Score(ctx RequestContext, n Node) float64 {
- return 1.0 / s.pred.Utilization(n)
+ // Cap utilization low limit at 5%. Anything below that is
+ // considered equally available.
+ u := s.pred.Utilization(n)
+ if u < 0.05 {
+ u = 0.05
+ }
+ return 1.0 / u
}
func NewCapacityAvailableScorer(pred Predictor) NodeFilter {
diff --git a/fe/loadbalancing_test.go b/fe/loadbalancing_test.go
index 4ca4ec09..2b3c7a49 100644
--- a/fe/loadbalancing_test.go
+++ b/fe/loadbalancing_test.go
@@ -115,6 +115,24 @@ func TestLoadBalancer_Policies(t *testing.T) {
runLBTest(t, nodes, nil, "bandwidth_score,best", 1000, map[string]int{"node2": 1000})
}
+func TestLoadBalancer_ZeroUtilization(t *testing.T) {
+ nodes := []*autoradio.NodeStatus{
+ &autoradio.NodeStatus{
+ Name: "node1",
+ IcecastUp: true,
+ BandwidthUsage: 0,
+ },
+ &autoradio.NodeStatus{
+ Name: "node2",
+ IcecastUp: true,
+ BandwidthUsage: 0,
+ },
+ }
+
+ // Weighted should return both nodes equally.
+ runLBTest(t, nodes, nil, "bandwidth_score,weighted", 1000, map[string]int{"node1": 500, "node2": 500})
+}
+
func TestLoadBalancer_PoliciesIgnoreDisabledNodes(t *testing.T) {
nodes := []*autoradio.NodeStatus{
&autoradio.NodeStatus{
--
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