Use middleware, and resolve some comments

cmd/service/service.go

@@ -16,6 +16,13 @@ func main() {
 	startServer()
 }
 
+func setContentType(next http.Handler) http.Handler {
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		w.Header().Set("Content-Type", "application/json")
+		next.ServeHTTP(w, r)
+	})
+}
+
 func startServer() {
 	router := http.NewServeMux()
 
@@ -35,10 +42,10 @@ func startServer() {
 		api.NewUpgrader(actionUpgrade),
 		api.NewHistory(actionHistory))
 
-	router.Handle("/ping", ping.Handler())
-	router.Handle("/list", api.List(service))
-	router.Handle("/install", api.Install(service))
-	router.Handle("/upgrade", api.Upgrade(service))
+	router.Handle("/ping", setContentType(ping.Handler()))
+	router.Handle("/list", setContentType(api.List(service)))
+	router.Handle("/install", setContentType(api.Install(service)))
+	router.Handle("/upgrade", setContentType(api.Upgrade(service)))
 
 	err := http.ListenAndServe(fmt.Sprintf(":%d", 8080), router)
 	if err != nil {

pkg/api/list.go

@@ -2,10 +2,11 @@ package api
 
 import (
 	"encoding/json"
+	"net/http"
+
 	"helm.sh/helm/v3/pkg/api/logger"
 	"helm.sh/helm/v3/pkg/release"
 	"helm.sh/helm/v3/pkg/time"
-	"net/http"
 )
 
 type ListRequest struct {
@@ -30,8 +31,6 @@ type Release struct {
 
 func List(svc Service) http.Handler {
 	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
-		w.Header().Set("Content-Type", "application/json")
-
 		var response ListResponse
 		var request ListRequest
 		decoder := json.NewDecoder(r.Body)

pkg/api/ping/pinghandler.go

@@ -8,8 +8,6 @@ import (
 
 func Handler() http.Handler {
 	return http.HandlerFunc(func(res http.ResponseWriter, req *http.Request) {
-
-		res.Header().Set("Content-Type", "application/json")
 		defer req.Body.Close()
 
 		var request Req

pkg/api/service.go

@@ -85,7 +85,7 @@ func (s Service) Upgrade(ctx context.Context, cfg ReleaseConfig, values ChartVal
 
 	if s.upgrader.GetInstall() {
 		if _, err := s.history.Run(cfg.Name); err == driver.ErrReleaseNotFound {
-			fmt.Printf("Release %q does not exist. Installing it now.\n", cfg.Name)
+			logger.Debugf("release %q does not exist. Installing it now.\n", cfg.Name)
 			return s.installChart(cfg, chart, vals)
 		}
 	}

pkg/api/service_test.go

@@ -3,9 +3,10 @@ package api_test
 import (
 	"context"
 	"errors"
-	"helm.sh/helm/v3/pkg/time"
 	"testing"
 
+	"helm.sh/helm/v3/pkg/time"
+
 	"helm.sh/helm/v3/pkg/action"
 	"helm.sh/helm/v3/pkg/api"
 

pkg/api/upgrade.go

@@ -22,7 +22,6 @@ type UpgradeResponse struct {
 
 func Upgrade(svc Service) http.Handler {
 	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
-		w.Header().Set("Content-Type", "application/json")
 		defer r.Body.Close()
 
 		var req UpgradeRequest