From f4efa2898be17cc4482702a363136f0778551869 Mon Sep 17 00:00:00 2001
From: Arjun <arjunrn@users.noreply.github.com>
Date: Fri, 1 Feb 2019 10:59:42 +0100
Subject: [PATCH] Handle condition when backend weights only sometimes present
 (#33)

Signed-off-by: Arjun Naik <arjun.rn@gmail.com>
---
 pkg/collector/skipper_collector.go      | 20 ++++++++++++--------
 pkg/collector/skipper_collector_test.go | 17 ++++++++++++++++-
 2 files changed, 28 insertions(+), 9 deletions(-)

diff --git a/pkg/collector/skipper_collector.go b/pkg/collector/skipper_collector.go
index 751a695..4c60c6a 100644
--- a/pkg/collector/skipper_collector.go
+++ b/pkg/collector/skipper_collector.go
@@ -81,29 +81,33 @@ func NewSkipperCollector(client kubernetes.Interface, plugin CollectorPlugin, hp
 	}, nil
 }
 
-func getAnnotationWeight(backendWeights string, backend string) float64 {
+func getAnnotationWeight(backendWeights string, backend string) (float64, bool) {
 	var weightsMap map[string]int
 	err := json.Unmarshal([]byte(backendWeights), &weightsMap)
 	if err != nil {
-		return 1
+		return 0, false
 	}
 	if weight, ok := weightsMap[backend]; ok {
-		return float64(weight) / 100
+		return float64(weight) / 100, true
 	}
-	return 1
+	return 0, false
 }
 
 func getWeights(ingressAnnotations map[string]string, backendAnnotations []string, backend string) float64 {
 	var maxWeight float64 = -1
+	weightSet := false
 	for _, anno := range backendAnnotations {
 		if weightsMap, ok := ingressAnnotations[anno]; ok {
-			weight := getAnnotationWeight(weightsMap, backend)
-			if weight > maxWeight {
-				maxWeight = weight
+			weight, isPresent := getAnnotationWeight(weightsMap, backend)
+			if isPresent {
+				weightSet = true
+				if weight > maxWeight {
+					maxWeight = weight
+				}
 			}
 		}
 	}
-	if maxWeight >= 0 {
+	if weightSet {
 		return maxWeight
 	}
 	return 1.0
diff --git a/pkg/collector/skipper_collector_test.go b/pkg/collector/skipper_collector_test.go
index 40281fa..f465433 100644
--- a/pkg/collector/skipper_collector_test.go
+++ b/pkg/collector/skipper_collector_test.go
@@ -180,12 +180,27 @@ func TestSkipperCollector(t *testing.T) {
 			ingressName:        "dummy-ingress",
 			collectedMetric:    1500,
 			namespace:          "default",
-			backend:            "",
+			backend:            "backend3",
 			backendWeights:     map[string]map[string]int{testBackendWeightsAnnotation: {"backend2": 100, "backend1": 0}},
 			replicas:           1,
 			readyReplicas:      1,
 			backendAnnotations: []string{testBackendWeightsAnnotation},
 		},
+		{
+			msg:             "test partial backend annotations",
+			metrics:         []int{100, 1500, 700},
+			ingressName:     "dummy-ingress",
+			collectedMetric: 60,
+			namespace:       "default",
+			backend:         "backend2",
+			backendWeights: map[string]map[string]int{
+				testBackendWeightsAnnotation:  {"backend2": 20, "backend1": 80},
+				testStacksetWeightsAnnotation: {"backend1": 100},
+			},
+			replicas:           5,
+			readyReplicas:      5,
+			backendAnnotations: []string{testBackendWeightsAnnotation, testStacksetWeightsAnnotation},
+		},
 	} {
 		t.Run(tc.msg, func(tt *testing.T) {
 			client := fake.NewSimpleClientset()