From 1235b8a647b16aa09d8b87b1f104dffabfc7257f Mon Sep 17 00:00:00 2001
From: "Nguyen Viet Hoang (Stephen)" <nguyen.viet.hoang.a@moneyforward.co.jp>
Date: Thu, 17 Oct 2024 23:25:47 +0900
Subject: [PATCH] chore: reduce cognitive complexity

---
 cmd/relayproxy/service/gofeatureflag.go | 83 ++++++++++++++++---------
 1 file changed, 54 insertions(+), 29 deletions(-)

diff --git a/cmd/relayproxy/service/gofeatureflag.go b/cmd/relayproxy/service/gofeatureflag.go
index 4d21218e380f..f0f41adb9c7f 100644
--- a/cmd/relayproxy/service/gofeatureflag.go
+++ b/cmd/relayproxy/service/gofeatureflag.go
@@ -41,75 +41,100 @@ func NewGoFeatureFlagClient(
 	logger *zap.Logger,
 	notifiers []notifier.Notifier,
 ) (*ffclient.GoFeatureFlag, error) {
-	var mainRetriever retriever.Retriever
-	var err error
-
 	if proxyConf == nil {
 		return nil, fmt.Errorf("proxy config is empty")
 	}
 
+	mainRetriever, retrievers, err := initRetrievers(proxyConf)
+	if err != nil {
+		return nil, err
+	}
+
+	mainDataExporter, dataExporters, err := initExporters(proxyConf)
+	if err != nil {
+		return nil, err
+	}
+
+	notif, err := initNotifiers(proxyConf.Notifiers, notifiers)
+	if err != nil {
+		return nil, err
+	}
+
+	f := ffclient.Config{
+		PollingInterval:                 time.Duration(proxyConf.PollingInterval) * time.Millisecond,
+		LeveledLogger:                   slog.New(slogzap.Option{Level: slog.LevelDebug, Logger: logger}.NewZapHandler()),
+		Context:                         context.Background(),
+		Retriever:                       mainRetriever,
+		Retrievers:                      retrievers,
+		Notifiers:                       notif,
+		FileFormat:                      proxyConf.FileFormat,
+		DataExporter:                    mainDataExporter,
+		DataExporters:                   dataExporters,
+		StartWithRetrieverError:         proxyConf.StartWithRetrieverError,
+		EnablePollingJitter:             proxyConf.EnablePollingJitter,
+		EvaluationContextEnrichment:     proxyConf.EvaluationContextEnrichment,
+		PersistentFlagConfigurationFile: proxyConf.PersistentFlagConfigurationFile,
+	}
+
+	return ffclient.New(f)
+}
+
+func initRetrievers(proxyConf *config.Config) (retriever.Retriever, []retriever.Retriever, error) {
+	var mainRetriever retriever.Retriever
+	var err error
+
 	if proxyConf.Retriever != nil {
 		mainRetriever, err = initRetriever(proxyConf.Retriever)
 		if err != nil {
-			return nil, err
+			return nil, nil, err
 		}
 	}
 
-	// Manage if we have more than 1 retriever
 	retrievers := make([]retriever.Retriever, 0)
 	if proxyConf.Retrievers != nil {
 		for _, r := range *proxyConf.Retrievers {
 			currentRetriever, err := initRetriever(&r)
 			if err != nil {
-				return nil, err
+				return nil, nil, err
 			}
 			retrievers = append(retrievers, currentRetriever)
 		}
 	}
 
+	return mainRetriever, retrievers, nil
+}
+
+func initExporters(proxyConf *config.Config) (ffclient.DataExporter, []ffclient.DataExporter, error) {
 	var mainDataExporter ffclient.DataExporter
+	var err error
+
 	if proxyConf.Exporter != nil {
 		mainDataExporter, err = initDataExporter(proxyConf.Exporter)
 		if err != nil {
-			return nil, err
+			return ffclient.DataExporter{}, nil, err
 		}
 	}
 
-	// Manage the case where we have multiple data exporters
 	dataExporters := make([]ffclient.DataExporter, 0)
 	if proxyConf.Exporters != nil {
 		for _, e := range *proxyConf.Exporters {
 			currentExporter, err := initDataExporter(&e)
 			if err != nil {
-				return nil, err
+				return ffclient.DataExporter{}, nil, err
 			}
 			dataExporters = append(dataExporters, currentExporter)
 		}
 	}
 
-	notif, err := initNotifier(proxyConf.Notifiers)
+	return mainDataExporter, dataExporters, nil
+}
+
+func initNotifiers(configNotifiers []config.NotifierConf, additionalNotifiers []notifier.Notifier) ([]notifier.Notifier, error) {
+	notif, err := initNotifier(configNotifiers)
 	if err != nil {
 		return nil, err
 	}
-	notif = append(notif, notifiers...)
-
-	f := ffclient.Config{
-		PollingInterval:                 time.Duration(proxyConf.PollingInterval) * time.Millisecond,
-		LeveledLogger:                   slog.New(slogzap.Option{Level: slog.LevelDebug, Logger: logger}.NewZapHandler()),
-		Context:                         context.Background(),
-		Retriever:                       mainRetriever,
-		Retrievers:                      retrievers,
-		Notifiers:                       notif,
-		FileFormat:                      proxyConf.FileFormat,
-		DataExporter:                    mainDataExporter,
-		DataExporters:                   dataExporters,
-		StartWithRetrieverError:         proxyConf.StartWithRetrieverError,
-		EnablePollingJitter:             proxyConf.EnablePollingJitter,
-		EvaluationContextEnrichment:     proxyConf.EvaluationContextEnrichment,
-		PersistentFlagConfigurationFile: proxyConf.PersistentFlagConfigurationFile,
-	}
-
-	return ffclient.New(f)
+	return append(notif, additionalNotifiers...), nil
 }
 
 // initRetriever initialize the retriever based on the configuration