Fix targeting filter parameter (#25)

* fix targeting filter parameter issue

* fix json tag

Author: linglingye001

featuremanagement/go.mod

@@ -1,3 +1,5 @@
 module github.com/microsoft/Featuremanagement-Go/featuremanagement
 
 go 1.23.0
+
+require github.com/go-viper/mapstructure/v2 v2.4.0

featuremanagement/go.sum

@@ -0,0 +1,2 @@
+github.com/go-viper/mapstructure/v2 v2.4.0 h1:EBsztssimR/CONLSZZ04E8qAkxNYq4Qp9LvH92wZUgs=
+github.com/go-viper/mapstructure/v2 v2.4.0/go.mod h1:oJDH3BJKyqBA2TXFhDsKDGDTlndYOZ6rGS0BRZIxGhM=

featuremanagement/targeting.go

@@ -6,36 +6,37 @@ package featuremanagement
 import (
 	"crypto/sha256"
 	"encoding/binary"
-	"encoding/json"
 	"fmt"
 	"math"
+
+	"github.com/go-viper/mapstructure/v2"
 )
 
 type TargetingFilter struct{}
 
 // TargetingGroup defines a named group with a specific rollout percentage
 type TargetingGroup struct {
-	Name              string  `json:"name"`
-	RolloutPercentage float64 `json:"rollout_percentage"`
+	Name              string
+	RolloutPercentage float64
 }
 
 // TargetingExclusion defines users and groups explicitly excluded from targeting
 type TargetingExclusion struct {
-	Users  []string `json:"users,omitempty"`
-	Groups []string `json:"groups,omitempty"`
+	Users  []string
+	Groups []string
 }
 
 // TargetingAudience defines the targeting configuration for feature rollout
 type TargetingAudience struct {
-	DefaultRolloutPercentage float64             `json:"default_rollout_percentage"`
-	Users                    []string            `json:"users,omitempty"`
-	Groups                   []TargetingGroup    `json:"groups,omitempty"`
-	Exclusion                *TargetingExclusion `json:"exclusion,omitempty"`
+	DefaultRolloutPercentage float64
+	Users                    []string
+	Groups                   []TargetingGroup
+	Exclusion                *TargetingExclusion
 }
 
 // TargetingFilterParameters defines the parameters for the targeting filter
 type TargetingFilterParameters struct {
-	Audience TargetingAudience `json:"audience"`
+	Audience TargetingAudience
 }
 
 func (t *TargetingFilter) Name() string {
@@ -102,15 +103,10 @@ func (t *TargetingFilter) Evaluate(evalCtx FeatureFilterEvaluationContext, appCt
 }
 
 func getTargetingParams(evalCtx FeatureFilterEvaluationContext) (TargetingFilterParameters, error) {
-	// First, unmarshal the parameters to our structured type
-	paramsBytes, err := json.Marshal(evalCtx.Parameters)
-	if err != nil {
-		return TargetingFilterParameters{}, fmt.Errorf("failed to marshal targeting parameters: %w", err)
-	}
-
 	var params TargetingFilterParameters
-	if err := json.Unmarshal(paramsBytes, &params); err != nil {
-		return TargetingFilterParameters{}, fmt.Errorf("invalid targeting parameters format: %w", err)
+	err := mapstructure.Decode(evalCtx.Parameters, &params)
+	if err != nil {
+		return TargetingFilterParameters{}, fmt.Errorf("failed to decode feature flag parameters: %v", err)
 	}
 
 	// Validate DefaultRolloutPercentage

featuremanagement/targeting_test.go

@@ -4,50 +4,48 @@
 package featuremanagement
 
 import (
-	"encoding/json"
 	"testing"
+
+	"github.com/go-viper/mapstructure/v2"
 )
 
 func TestTargetingFilter(t *testing.T) {
-	// Define the test feature flag with complex targeting rules
-	jsonData := `{
-        "id": "ComplexTargeting",
-        "description": "A feature flag using a targeting filter, that will return true for Alice, Stage1, and 50% of Stage2. Dave and Stage3 are excluded. The default rollout percentage is 25%.",
-        "enabled": true,
-        "conditions": {
-            "client_filters": [
-                {
-                    "name": "Microsoft.Targeting",
-                    "parameters": {
-                        "audience": {
-                            "users": [
-                                "Alice"
-                            ],
-                            "groups": [
-                                {
-                                    "name": "Stage1",
-                                    "rollout_percentage": 100
-                                },
-                                {
-                                    "name": "Stage2",
-                                    "rollout_percentage": 50
-                                }
-                            ],
-                            "default_rollout_percentage": 25,
-                            "exclusion": {
-                                "users": ["Dave"],
-                                "groups": ["Stage3"]
-                            }
-                        }
-                    }
-                }
-            ]
-        }
-    }`
+	featureFlagData := map[string]any{
+		"ID":          "ComplexTargeting",
+		"Description": "A feature flag using a targeting filter, that will return true for Alice, Stage1, and 50% of Stage2. Dave and Stage3 are excluded. The default rollout percentage is 25%.",
+		"Enabled":     true,
+		"Conditions": map[string]any{
+			"ClientFilters": []any{
+				map[string]any{
+					"Name": "Microsoft.Targeting",
+					"Parameters": map[string]any{
+						"Audience": map[string]any{
+							"Users": []any{"Alice"},
+							"Groups": []any{
+								map[string]any{
+									"Name":              "Stage1",
+									"RolloutPercentage": 100,
+								},
+								map[string]any{
+									"Name":              "Stage2",
+									"RolloutPercentage": 50,
+								},
+							},
+							"DefaultRolloutPercentage": 25,
+							"Exclusion": map[string]any{
+								"Users":  []any{"Dave"},
+								"Groups": []any{"Stage3"},
+							},
+						},
+					},
+				},
+			},
+		},
+	}
 
-	// Parse the JSON
 	var featureFlag FeatureFlag
-	if err := json.Unmarshal([]byte(jsonData), &featureFlag); err != nil {
+	err := mapstructure.Decode(featureFlagData, &featureFlag)
+	if err != nil {
 		t.Fatalf("Failed to parse feature flag JSON: %v", err)
 	}