Add back consumeAndClose functionality. (#7608)

* consume bodies for action button integrations, webrtc gateway, oauth
endpoint

* Fixing a couple more places, switching to io.Copy to ioutil.Discard, adding a comment to help prevent future performance regressions

app/notification.go

@@ -7,7 +7,6 @@ import (
 	"fmt"
 	"html"
 	"html/template"
-	"io/ioutil"
 	"net/http"
 	"net/url"
 	"path/filepath"
@@ -701,8 +700,7 @@ func (a *App) sendToPushProxy(msg model.PushNotification, session *model.Session
 	} else {
 		pushResponse := model.PushResponseFromJson(resp.Body)
 		if resp.Body != nil {
-			ioutil.ReadAll(resp.Body)
-			resp.Body.Close()
+			consumeAndClose(resp)
 		}
 
 		if pushResponse[model.PUSH_STATUS] == model.PUSH_STATUS_REMOVE {

app/oauth.go

@@ -685,7 +685,7 @@ func (a *App) AuthorizeOAuthUser(w http.ResponseWriter, r *http.Request, service
 		return nil, "", stateProps, model.NewAppError("AuthorizeOAuthUser", "api.user.authorize_oauth_user.token_failed.app_error", nil, err.Error(), http.StatusInternalServerError)
 	} else {
 		ar = model.AccessResponseFromJson(resp.Body)
-		resp.Body.Close()
+		consumeAndClose(resp)
 
 		if ar == nil {
 			return nil, "", stateProps, model.NewAppError("AuthorizeOAuthUser", "api.user.authorize_oauth_user.bad_response.app_error", nil, "response_body="+string(bodyBytes), http.StatusInternalServerError)

app/post.go

@@ -676,7 +676,7 @@ func GetOpenGraphMetadata(url string) *opengraph.OpenGraph {
 		l4g.Error("GetOpenGraphMetadata request failed for url=%v with err=%v", url, err.Error())
 		return og
 	}
-	defer res.Body.Close()
+	defer consumeAndClose(res)
 
 	if err := og.ProcessHTML(res.Body); err != nil {
 		l4g.Error("GetOpenGraphMetadata processing failed for url=%v with err=%v", url, err.Error())
@@ -712,7 +712,7 @@ func (a *App) DoPostAction(postId string, actionId string, userId string) *model
 	if err != nil {
 		return model.NewAppError("DoPostAction", "api.post.do_action.action_integration.app_error", nil, "err="+err.Error(), http.StatusBadRequest)
 	}
-	defer resp.Body.Close()
+	defer consumeAndClose(resp)
 
 	if resp.StatusCode != http.StatusOK {
 		return model.NewAppError("DoPostAction", "api.post.do_action.action_integration.app_error", nil, fmt.Sprintf("status=%v", resp.StatusCode), http.StatusBadRequest)

app/security_update_check.go

@@ -80,8 +80,7 @@ func (a *App) DoSecurityUpdateCheck() {
 				}
 
 				bulletins := model.SecurityBulletinsFromJson(res.Body)
-				ioutil.ReadAll(res.Body)
-				res.Body.Close()
+				consumeAndClose(res)
 
 				for _, bulletin := range bulletins {
 					if bulletin.AppliesToVersion == model.CurrentVersion {

app/server.go

@@ -5,6 +5,8 @@ package app
 
 import (
 	"crypto/tls"
+	"io"
+	"io/ioutil"
 	"net"
 	"net/http"
 	"strings"
@@ -208,3 +210,11 @@ func (a *App) StopServer() {
 		a.Srv.GracefulServer = nil
 	}
 }
+
+// This is required to re-use the underlying connection and not take up file descriptors
+func consumeAndClose(r *http.Response) {
+	if r.Body != nil {
+		io.Copy(ioutil.Discard, r.Body)
+		r.Body.Close()
+	}
+}

app/webhook.go

@@ -109,7 +109,7 @@ func (a *App) TriggerWebhook(payload *model.OutgoingWebhookPayload, hook *model.
 				if resp, err := utils.HttpClient(false).Do(req); err != nil {
 					l4g.Error(utils.T("api.post.handle_webhook_events_and_forget.event_post.error"), err.Error())
 				} else {
-					defer resp.Body.Close()
+					defer consumeAndClose(resp)
 					webhookResp := model.OutgoingWebhookResponseFromJson(resp.Body)
 
 					if webhookResp != nil && webhookResp.Text != nil {

app/webrtc.go

@@ -62,7 +62,7 @@ func GetWebrtcToken(sessionId string) (string, *model.AppError) {
 	if rp, err := utils.HttpClient(true).Do(rq); err != nil {
 		return "", model.NewAppError("WebRTC.Token", "model.client.connecting.app_error", nil, err.Error(), http.StatusInternalServerError)
 	} else if rp.StatusCode >= 300 {
-		defer rp.Body.Close()
+		defer consumeAndClose(rp)
 		return "", model.AppErrorFromJson(rp.Body)
 	} else {
 		janusResponse := model.GatewayResponseFromJson(rp.Body)