Add Support for Target App Condition (#266)

kong test: statsig-io/kong#3431

Author: sroyal-statsig

client_initialize_response.go

@@ -100,6 +100,14 @@ func getClientInitializeResponse(
 		hashAlgorithm = "sha256"
 	}
 
+	var appId string
+	if context.TargetAppID != "" {
+		appId = context.TargetAppID
+	} else {
+		appId, _ = e.store.getAppIDForSDKKey(context.ClientKey)
+		context.TargetAppID = appId
+	}
+
 	evalResultToBaseResponse := func(name string, eval *evalResult) (string, baseSpecInitializeResponse) {
 		hashedName := hashName(hashAlgorithm, name)
 		result := baseSpecInitializeResponse{
@@ -221,13 +229,6 @@ func getClientInitializeResponse(
 		return hashedName, result
 	}
 
-	var appId string
-	if context.TargetAppID != "" {
-		appId = context.TargetAppID
-	} else {
-		appId, _ = e.store.getAppIDForSDKKey(context.ClientKey)
-	}
-
 	filterByEntities := false
 	gatesLookup := make(map[string]bool)
 	configsLookup := make(map[string]bool)

evaluator.go

@@ -563,6 +563,12 @@ func (e *evaluator) evalCondition(user User, cond configCondition, depth int, co
 		}
 	case strings.EqualFold(condType, "unit_id"):
 		value = getUnitID(user, cond.IDType)
+	case strings.EqualFold(condType, "target_app"):
+		if (context.ClientKey != "") {
+			value = context.TargetAppID
+		} else {
+			value = e.store.getAppID()
+		}
 	default:
 		return &evalResult{Unsupported: true}
 	}

store.go

@@ -94,6 +94,7 @@ type downloadConfigSpecResponse struct {
 	HashedSDKKeyUsed        string                    `json:"hashed_sdk_key_used,omitempty"`
 	SDKFlags                map[string]bool           `json:"sdk_flags,omitempty"`
 	SDKConfigs              map[string]interface{}    `json:"sdk_configs,omitempty"`
+	AppID					string                    `json:"app_id,omitempty"`
 }
 
 type configEntities struct {
@@ -145,6 +146,7 @@ type store struct {
 	isPolling               bool
 	bootstrapValues         string
 	sdkConfigs              *SDKConfigs
+	AppID                   string
 }
 
 var syncOutdatedMax = 2 * time.Minute
@@ -299,6 +301,12 @@ func (s *store) getAppIDForSDKKey(clientKey string) (string, bool) {
 	return appId, ok
 }
 
+func (s *store) getAppID() string {
+	s.mu.RLock()
+	defer s.mu.RUnlock()
+	return s.AppID
+}
+
 func (s *store) getEntitiesForSDKKey(clientKey string) (configEntities, bool) {
 	s.mu.RLock()
 	defer s.mu.RUnlock()
@@ -496,6 +504,7 @@ func (s *store) setConfigSpecs(specs downloadConfigSpecResponse) (bool, bool) {
 		s.hashedSDKKeysToAppID = specs.HashedSDKKeysToAppID
 		s.hashedSDKKeysToEntities = specs.HashedSDKKeysToEntities
 		s.lastSyncTime = specs.Time
+		s.AppID = specs.AppID
 		s.mu.Unlock()
 		return true, true
 	}