Merge pull request #27 from drone/FFM-1108

[FFM-1108]: Add a log when the segment in variation map is invalid

Author: hannah-tang

evaluation/feature.go

@@ -6,6 +6,8 @@ import (
 	"reflect"
 	"strconv"
 
+	"github.com/labstack/gommon/log"
+
 	"github.com/drone/ff-golang-server-sdk/types"
 )
 
@@ -227,11 +229,15 @@ func (fc FeatureConfig) GetVariationName(target *Target) string {
 
 				if variationMap.TargetSegments != nil {
 					for _, segmentIdentifier := range variationMap.TargetSegments {
-						segment := fc.Segments[segmentIdentifier]
-						if segment.Included != nil {
-							for _, t := range segment.Included {
-								if t == target.Identifier {
-									return variationMap.Variation
+						segment, ok := fc.Segments[segmentIdentifier]
+						if !ok {
+							log.Error("The segment in variation map is invalid")
+						} else {
+							if segment.Included != nil {
+								for _, t := range segment.Included {
+									if t == target.Identifier {
+										return variationMap.Variation
+									}
 								}
 							}
 						}

go.mod

@@ -11,6 +11,7 @@ require (
 	github.com/hashicorp/golang-lru v0.5.4
 	github.com/jarcoal/httpmock v1.0.8
 	github.com/json-iterator/go v1.1.10
+	github.com/labstack/gommon v0.3.0 // indirect
 	github.com/mitchellh/go-homedir v1.1.0
 	github.com/mitchellh/mapstructure v1.3.3
 	github.com/r3labs/sse v0.0.0-20201126193848-34e640891548