Extracting html templates into a library (#16946)

* Extracting html templates into a library

* Moving tests to the right place

* Fixing tests

* Addressing PR review comments

* Addressing PR review comments

* Replacing attomic with RWMutex

* Returning errors as channel for Templates watcher

* Address PR review comments

* Other small fixes

* Simplifying NewWithWatcher

* Addressing PR review comments

* Making error handling on rendering templates more robust

* Fixing tests

* Changing how we return errors

* Fixing shadow variables

* Addressing PR review comments

* Logging errors from the outside of sendNotificationEmail

* Fixing lock in shutdown

* Fixing the resource copy for commands tests temporary directories

* Removing unused import

* A couple of tiny fixes

app/app.go

@@ -6,7 +6,6 @@ package app
 import (
 	"context"
 	"fmt"
-	"html/template"
 	"net/http"
 	"strconv"
 	"strings"
@@ -21,6 +20,7 @@ import (
 	"github.com/mattermost/mattermost-server/v5/services/timezones"
 	"github.com/mattermost/mattermost-server/v5/shared/i18n"
 	"github.com/mattermost/mattermost-server/v5/shared/mlog"
+	"github.com/mattermost/mattermost-server/v5/shared/templates"
 	"github.com/mattermost/mattermost-server/v5/utils"
 )
 
@@ -148,12 +148,8 @@ func (a *App) TelemetryId() string {
 	return a.Srv().TelemetryId()
 }
 
-func (s *Server) HTMLTemplates() *template.Template {
-	if s.htmlTemplateWatcher != nil {
-		return s.htmlTemplateWatcher.Templates()
-	}
-
-	return nil
+func (s *Server) TemplatesContainer() *templates.Container {
+	return s.htmlTemplateWatcher
 }
 
 func (a *App) Handle404(w http.ResponseWriter, r *http.Request) {
@@ -467,25 +463,25 @@ func (a *App) NotifyAndSetWarnMetricAck(warnMetricId string, sender *model.User,
 				return model.NewAppError("NotifyAndSetWarnMetricAck", "api.email.send_warn_metric_ack.missing_server.app_error", nil, i18n.T("api.context.invalid_param.app_error", map[string]interface{}{"Name": "SMTPServer"}), http.StatusInternalServerError)
 			}
 			T := i18n.GetUserTranslations(sender.Locale)
-			bodyPage := a.Srv().EmailService.newEmailTemplate("warn_metric_ack", sender.Locale)
-			bodyPage.Props["ContactNameHeader"] = T("api.templates.warn_metric_ack.body.contact_name_header")
-			bodyPage.Props["ContactNameValue"] = sender.GetFullName()
-			bodyPage.Props["ContactEmailHeader"] = T("api.templates.warn_metric_ack.body.contact_email_header")
-			bodyPage.Props["ContactEmailValue"] = sender.Email
+			data := a.Srv().EmailService.newEmailTemplateData(sender.Locale)
+			data.Props["ContactNameHeader"] = T("api.templates.warn_metric_ack.body.contact_name_header")
+			data.Props["ContactNameValue"] = sender.GetFullName()
+			data.Props["ContactEmailHeader"] = T("api.templates.warn_metric_ack.body.contact_email_header")
+			data.Props["ContactEmailValue"] = sender.Email
 
 			//same definition as the active users count metric displayed in the SystemConsole Analytics section
 			registeredUsersCount, cerr := a.Srv().Store.User().Count(model.UserCountOptions{})
 			if cerr != nil {
 				mlog.Warn("Error retrieving the number of registered users", mlog.Err(cerr))
 			} else {
-				bodyPage.Props["RegisteredUsersHeader"] = T("api.templates.warn_metric_ack.body.registered_users_header")
-				bodyPage.Props["RegisteredUsersValue"] = registeredUsersCount
+				data.Props["RegisteredUsersHeader"] = T("api.templates.warn_metric_ack.body.registered_users_header")
+				data.Props["RegisteredUsersValue"] = registeredUsersCount
 			}
-			bodyPage.Props["SiteURLHeader"] = T("api.templates.warn_metric_ack.body.site_url_header")
-			bodyPage.Props["SiteURL"] = a.GetSiteURL()
-			bodyPage.Props["TelemetryIdHeader"] = T("api.templates.warn_metric_ack.body.diagnostic_id_header")
-			bodyPage.Props["TelemetryIdValue"] = a.TelemetryId()
-			bodyPage.Props["Footer"] = T("api.templates.warn_metric_ack.footer")
+			data.Props["SiteURLHeader"] = T("api.templates.warn_metric_ack.body.site_url_header")
+			data.Props["SiteURL"] = a.GetSiteURL()
+			data.Props["TelemetryIdHeader"] = T("api.templates.warn_metric_ack.body.diagnostic_id_header")
+			data.Props["TelemetryIdValue"] = a.TelemetryId()
+			data.Props["Footer"] = T("api.templates.warn_metric_ack.footer")
 
 			warnMetricStatus, warnMetricDisplayTexts := a.getWarnMetricStatusAndDisplayTextsForId(warnMetricId, T, false)
 			if warnMetricStatus == nil {
@@ -493,10 +489,16 @@ func (a *App) NotifyAndSetWarnMetricAck(warnMetricId string, sender *model.User,
 			}
 
 			subject := T("api.templates.warn_metric_ack.subject")
-			bodyPage.Props["Title"] = warnMetricDisplayTexts.EmailBody
+			data.Props["Title"] = warnMetricDisplayTexts.EmailBody
 
 			mailConfig := a.Srv().MailServiceConfig()
-			if err := mailservice.SendMailUsingConfig(model.MM_SUPPORT_ADVISOR_ADDRESS, subject, bodyPage.Render(), mailConfig, false, sender.Email); err != nil {
+
+			body, err := a.Srv().TemplatesContainer().RenderToString("warn_metric_ack", data)
+			if err != nil {
+				return model.NewAppError("NotifyAndSetWarnMetricAck", "api.email.send_warn_metric_ack.failure.app_error", map[string]interface{}{"Error": err.Error()}, "", http.StatusInternalServerError)
+			}
+
+			if err := mailservice.SendMailUsingConfig(model.MM_SUPPORT_ADVISOR_ADDRESS, subject, body, mailConfig, false, sender.Email); err != nil {
 				return model.NewAppError("NotifyAndSetWarnMetricAck", "api.email.send_warn_metric_ack.failure.app_error", map[string]interface{}{"Error": err.Error()}, "", http.StatusInternalServerError)
 			}
 		}

app/email.go

@@ -7,6 +7,7 @@ import (
 	"bytes"
 	"encoding/json"
 	"fmt"
+	"html/template"
 	"io"
 	"net/http"
 	"net/url"
@@ -22,7 +23,7 @@ import (
 	"github.com/mattermost/mattermost-server/v5/services/mailservice"
 	"github.com/mattermost/mattermost-server/v5/shared/i18n"
 	"github.com/mattermost/mattermost-server/v5/shared/mlog"
-	"github.com/mattermost/mattermost-server/v5/utils"
+	"github.com/mattermost/mattermost-server/v5/shared/templates"
 )
 
 const (
@@ -94,14 +95,19 @@ func (es *EmailService) sendChangeUsernameEmail(newUsername, email, locale, site
 		map[string]interface{}{"SiteName": es.srv.Config().TeamSettings.SiteName,
 			"TeamDisplayName": es.srv.Config().TeamSettings.SiteName})
 
-	bodyPage := es.newEmailTemplate("email_change_body", locale)
-	bodyPage.Props["SiteURL"] = siteURL
-	bodyPage.Props["Title"] = T("api.templates.username_change_body.title")
-	bodyPage.Props["Info"] = T("api.templates.username_change_body.info",
+	data := es.newEmailTemplateData(locale)
+	data.Props["SiteURL"] = siteURL
+	data.Props["Title"] = T("api.templates.username_change_body.title")
+	data.Props["Info"] = T("api.templates.username_change_body.info",
 		map[string]interface{}{"TeamDisplayName": es.srv.Config().TeamSettings.SiteName, "NewUsername": newUsername})
-	bodyPage.Props["Warning"] = T("api.templates.email_warning")
+	data.Props["Warning"] = T("api.templates.email_warning")
 
-	if err := es.sendMail(email, subject, bodyPage.Render()); err != nil {
+	body, err := es.srv.TemplatesContainer().RenderToString("email_change_body", data)
+	if err != nil {
+		return model.NewAppError("sendChangeUsernameEmail", "api.user.send_email_change_username_and_forget.error", nil, err.Error(), http.StatusInternalServerError)
+	}
+
+	if err := es.sendMail(email, subject, body); err != nil {
 		return model.NewAppError("sendChangeUsernameEmail", "api.user.send_email_change_username_and_forget.error", nil, err.Error(), http.StatusInternalServerError)
 	}
 
@@ -117,15 +123,20 @@ func (es *EmailService) sendEmailChangeVerifyEmail(newUserEmail, locale, siteURL
 		map[string]interface{}{"SiteName": es.srv.Config().TeamSettings.SiteName,
 			"TeamDisplayName": es.srv.Config().TeamSettings.SiteName})
 
-	bodyPage := es.newEmailTemplate("email_change_verify_body", locale)
-	bodyPage.Props["SiteURL"] = siteURL
-	bodyPage.Props["Title"] = T("api.templates.email_change_verify_body.title")
-	bodyPage.Props["Info"] = T("api.templates.email_change_verify_body.info",
+	data := es.newEmailTemplateData(locale)
+	data.Props["SiteURL"] = siteURL
+	data.Props["Title"] = T("api.templates.email_change_verify_body.title")
+	data.Props["Info"] = T("api.templates.email_change_verify_body.info",
 		map[string]interface{}{"TeamDisplayName": es.srv.Config().TeamSettings.SiteName})
-	bodyPage.Props["VerifyUrl"] = link
-	bodyPage.Props["VerifyButton"] = T("api.templates.email_change_verify_body.button")
+	data.Props["VerifyUrl"] = link
+	data.Props["VerifyButton"] = T("api.templates.email_change_verify_body.button")
 
-	if err := es.sendMail(newUserEmail, subject, bodyPage.Render()); err != nil {
+	body, err := es.srv.TemplatesContainer().RenderToString("email_change_verify_body", data)
+	if err != nil {
+		return model.NewAppError("sendEmailChangeVerifyEmail", "api.user.send_email_change_verify_email_and_forget.error", nil, err.Error(), http.StatusInternalServerError)
+	}
+
+	if err := es.sendMail(newUserEmail, subject, body); err != nil {
 		return model.NewAppError("sendEmailChangeVerifyEmail", "api.user.send_email_change_verify_email_and_forget.error", nil, err.Error(), http.StatusInternalServerError)
 	}
 
@@ -139,14 +150,19 @@ func (es *EmailService) sendEmailChangeEmail(oldEmail, newEmail, locale, siteURL
 		map[string]interface{}{"SiteName": es.srv.Config().TeamSettings.SiteName,
 			"TeamDisplayName": es.srv.Config().TeamSettings.SiteName})
 
-	bodyPage := es.newEmailTemplate("email_change_body", locale)
-	bodyPage.Props["SiteURL"] = siteURL
-	bodyPage.Props["Title"] = T("api.templates.email_change_body.title")
-	bodyPage.Props["Info"] = T("api.templates.email_change_body.info",
+	data := es.newEmailTemplateData(locale)
+	data.Props["SiteURL"] = siteURL
+	data.Props["Title"] = T("api.templates.email_change_body.title")
+	data.Props["Info"] = T("api.templates.email_change_body.info",
 		map[string]interface{}{"TeamDisplayName": es.srv.Config().TeamSettings.SiteName, "NewEmail": newEmail})
-	bodyPage.Props["Warning"] = T("api.templates.email_warning")
+	data.Props["Warning"] = T("api.templates.email_warning")
 
-	if err := es.sendMail(oldEmail, subject, bodyPage.Render()); err != nil {
+	body, err := es.srv.TemplatesContainer().RenderToString("email_change_body", data)
+	if err != nil {
+		return model.NewAppError("sendEmailChangeEmail", "api.user.send_email_change_email_and_forget.error", nil, err.Error(), http.StatusInternalServerError)
+	}
+
+	if err := es.sendMail(oldEmail, subject, body); err != nil {
 		return model.NewAppError("sendEmailChangeEmail", "api.user.send_email_change_email_and_forget.error", nil, err.Error(), http.StatusInternalServerError)
 	}
 
@@ -166,20 +182,25 @@ func (es *EmailService) sendVerifyEmail(userEmail, locale, siteURL, token, redir
 	subject := T("api.templates.verify_subject",
 		map[string]interface{}{"SiteName": es.srv.Config().TeamSettings.SiteName})
 
-	bodyPage := es.newEmailTemplate("verify_body", locale)
-	bodyPage.Props["SiteURL"] = siteURL
-	bodyPage.Props["Title"] = T("api.templates.verify_body.title")
-	bodyPage.Props["SubTitle1"] = T("api.templates.verify_body.subTitle1")
-	bodyPage.Props["ServerURL"] = T("api.templates.verify_body.serverURL", map[string]interface{}{"ServerURL": serverURL})
-	bodyPage.Props["SubTitle2"] = T("api.templates.verify_body.subTitle2")
-	bodyPage.Props["ButtonURL"] = link
-	bodyPage.Props["Button"] = T("api.templates.verify_body.button")
-	bodyPage.Props["Info"] = T("api.templates.verify_body.info")
-	bodyPage.Props["Info1"] = T("api.templates.verify_body.info1")
-	bodyPage.Props["QuestionTitle"] = T("api.templates.questions_footer.title")
-	bodyPage.Props["QuestionInfo"] = T("api.templates.questions_footer.info")
+	data := es.newEmailTemplateData(locale)
+	data.Props["SiteURL"] = siteURL
+	data.Props["Title"] = T("api.templates.verify_body.title")
+	data.Props["SubTitle1"] = T("api.templates.verify_body.subTitle1")
+	data.Props["ServerURL"] = T("api.templates.verify_body.serverURL", map[string]interface{}{"ServerURL": serverURL})
+	data.Props["SubTitle2"] = T("api.templates.verify_body.subTitle2")
+	data.Props["ButtonURL"] = link
+	data.Props["Button"] = T("api.templates.verify_body.button")
+	data.Props["Info"] = T("api.templates.verify_body.info")
+	data.Props["Info1"] = T("api.templates.verify_body.info1")
+	data.Props["QuestionTitle"] = T("api.templates.questions_footer.title")
+	data.Props["QuestionInfo"] = T("api.templates.questions_footer.info")
 
-	if err := es.sendMail(userEmail, subject, bodyPage.Render()); err != nil {
+	body, err := es.srv.TemplatesContainer().RenderToString("verify_body", data)
+	if err != nil {
+		return model.NewAppError("SendVerifyEmail", "api.user.send_verify_email_and_forget.failed.error", nil, err.Error(), http.StatusInternalServerError)
+	}
+
+	if err := es.sendMail(userEmail, subject, body); err != nil {
 		return model.NewAppError("SendVerifyEmail", "api.user.send_verify_email_and_forget.failed.error", nil, err.Error(), http.StatusInternalServerError)
 	}
 
@@ -192,14 +213,19 @@ func (es *EmailService) SendSignInChangeEmail(email, method, locale, siteURL str
 	subject := T("api.templates.signin_change_email.subject",
 		map[string]interface{}{"SiteName": es.srv.Config().TeamSettings.SiteName})
 
-	bodyPage := es.newEmailTemplate("signin_change_body", locale)
-	bodyPage.Props["SiteURL"] = siteURL
-	bodyPage.Props["Title"] = T("api.templates.signin_change_email.body.title")
-	bodyPage.Props["Info"] = T("api.templates.signin_change_email.body.info",
+	data := es.newEmailTemplateData(locale)
+	data.Props["SiteURL"] = siteURL
+	data.Props["Title"] = T("api.templates.signin_change_email.body.title")
+	data.Props["Info"] = T("api.templates.signin_change_email.body.info",
 		map[string]interface{}{"SiteName": es.srv.Config().TeamSettings.SiteName, "Method": method})
-	bodyPage.Props["Warning"] = T("api.templates.email_warning")
+	data.Props["Warning"] = T("api.templates.email_warning")
 
-	if err := es.sendMail(email, subject, bodyPage.Render()); err != nil {
+	body, err := es.srv.TemplatesContainer().RenderToString("signin_change_body", data)
+	if err != nil {
+		return model.NewAppError("SendSignInChangeEmail", "api.user.send_sign_in_change_email_and_forget.error", nil, err.Error(), http.StatusInternalServerError)
+	}
+
+	if err := es.sendMail(email, subject, body); err != nil {
 		return model.NewAppError("SendSignInChangeEmail", "api.user.send_sign_in_change_email_and_forget.error", nil, err.Error(), http.StatusInternalServerError)
 	}
 
@@ -222,22 +248,22 @@ func (es *EmailService) sendWelcomeEmail(userID string, email string, verified b
 		map[string]interface{}{"SiteName": es.srv.Config().TeamSettings.SiteName,
 			"ServerURL": serverURL})
 
-	bodyPage := es.newEmailTemplate("welcome_body", locale)
-	bodyPage.Props["SiteURL"] = siteURL
-	bodyPage.Props["Title"] = T("api.templates.welcome_body.title")
-	bodyPage.Props["SubTitle1"] = T("api.templates.welcome_body.subTitle1")
-	bodyPage.Props["ServerURL"] = T("api.templates.welcome_body.serverURL", map[string]interface{}{"ServerURL": serverURL})
-	bodyPage.Props["SubTitle2"] = T("api.templates.welcome_body.subTitle2")
-	bodyPage.Props["Button"] = T("api.templates.welcome_body.button")
-	bodyPage.Props["Info"] = T("api.templates.welcome_body.info")
-	bodyPage.Props["Info1"] = T("api.templates.welcome_body.info1")
-	bodyPage.Props["SiteURL"] = siteURL
+	data := es.newEmailTemplateData(locale)
+	data.Props["SiteURL"] = siteURL
+	data.Props["Title"] = T("api.templates.welcome_body.title")
+	data.Props["SubTitle1"] = T("api.templates.welcome_body.subTitle1")
+	data.Props["ServerURL"] = T("api.templates.welcome_body.serverURL", map[string]interface{}{"ServerURL": serverURL})
+	data.Props["SubTitle2"] = T("api.templates.welcome_body.subTitle2")
+	data.Props["Button"] = T("api.templates.welcome_body.button")
+	data.Props["Info"] = T("api.templates.welcome_body.info")
+	data.Props["Info1"] = T("api.templates.welcome_body.info1")
+	data.Props["SiteURL"] = siteURL
 
 	if *es.srv.Config().NativeAppSettings.AppDownloadLink != "" {
-		bodyPage.Props["AppDownloadTitle"] = T("api.templates.welcome_body.app_download_title")
-		bodyPage.Props["AppDownloadInfo"] = T("api.templates.welcome_body.app_download_info")
-		bodyPage.Props["AppDownloadButton"] = T("api.templates.welcome_body.app_download_button")
-		bodyPage.Props["AppDownloadLink"] = *es.srv.Config().NativeAppSettings.AppDownloadLink
+		data.Props["AppDownloadTitle"] = T("api.templates.welcome_body.app_download_title")
+		data.Props["AppDownloadInfo"] = T("api.templates.welcome_body.app_download_info")
+		data.Props["AppDownloadButton"] = T("api.templates.welcome_body.app_download_button")
+		data.Props["AppDownloadLink"] = *es.srv.Config().NativeAppSettings.AppDownloadLink
 	}
 
 	if !verified && *es.srv.Config().EmailSettings.RequireEmailVerification {
@@ -249,10 +275,15 @@ func (es *EmailService) sendWelcomeEmail(userID string, email string, verified b
 		if redirect != "" {
 			link += fmt.Sprintf("&redirect_to=%s", redirect)
 		}
-		bodyPage.Props["ButtonURL"] = link
+		data.Props["ButtonURL"] = link
 	}
 
-	if err := es.sendMail(email, subject, bodyPage.Render()); err != nil {
+	body, err := es.srv.TemplatesContainer().RenderToString("welcome_body", data)
+	if err != nil {
+		return model.NewAppError("sendWelcomeEmail", "api.user.send_welcome_email_and_forget.failed.error", nil, err.Error(), http.StatusInternalServerError)
+	}
+
+	if err := es.sendMail(email, subject, body); err != nil {
 		return model.NewAppError("sendWelcomeEmail", "api.user.send_welcome_email_and_forget.failed.error", nil, err.Error(), http.StatusInternalServerError)
 	}
 
@@ -266,30 +297,35 @@ func (es *EmailService) SendCloudWelcomeEmail(userEmail, locale, teamInviteID, w
 
 	workSpacePath := fmt.Sprintf("https://%s.cloud.mattermost.com", workSpaceName)
 
-	bodyPage := es.newEmailTemplate("cloud_welcome_email", locale)
-	bodyPage.Props["Title"] = T("api.templates.cloud_welcome_email.title", map[string]interface{}{"WorkSpace": workSpaceName})
-	bodyPage.Props["SubTitle"] = T("api.templates.cloud_welcome_email.subtitle")
-	bodyPage.Props["SubTitleInfo"] = T("api.templates.cloud_welcome_email.subtitle_info")
-	bodyPage.Props["Info"] = T("api.templates.cloud_welcome_email.info")
-	bodyPage.Props["Info2"] = T("api.templates.cloud_welcome_email.info2")
-	bodyPage.Props["WorkSpacePath"] = workSpacePath
-	bodyPage.Props["DNS"] = dns
-	bodyPage.Props["InviteInfo"] = T("api.templates.cloud_welcome_email.invite_info")
-	bodyPage.Props["InviteSubInfo"] = T("api.templates.cloud_welcome_email.invite_sub_info", map[string]interface{}{"WorkSpace": workSpaceName})
-	bodyPage.Props["InviteSubInfoLink"] = fmt.Sprintf("%s/signup_user_complete/?id=%s", workSpacePath, teamInviteID)
-	bodyPage.Props["AddAppsInfo"] = T("api.templates.cloud_welcome_email.add_apps_info")
-	bodyPage.Props["AddAppsSubInfo"] = T("api.templates.cloud_welcome_email.add_apps_sub_info")
-	bodyPage.Props["AppMarketPlace"] = T("api.templates.cloud_welcome_email.app_market_place")
-	bodyPage.Props["AppMarketPlaceLink"] = "https://integrations.mattermost.com/"
-	bodyPage.Props["DownloadMMInfo"] = T("api.templates.cloud_welcome_email.download_mm_info")
-	bodyPage.Props["SignInSubInfo"] = T("api.templates.cloud_welcome_email.signin_sub_info")
-	bodyPage.Props["MMApps"] = T("api.templates.cloud_welcome_email.mm_apps")
-	bodyPage.Props["SignInSubInfo2"] = T("api.templates.cloud_welcome_email.signin_sub_info2")
-	bodyPage.Props["DownloadMMAppsLink"] = "https://mattermost.com/download/"
-	bodyPage.Props["Button"] = T("api.templates.cloud_welcome_email.button")
-	bodyPage.Props["GettingStartedQuestions"] = T("api.templates.cloud_welcome_email.start_questions")
+	data := es.newEmailTemplateData(locale)
+	data.Props["Title"] = T("api.templates.cloud_welcome_email.title", map[string]interface{}{"WorkSpace": workSpaceName})
+	data.Props["SubTitle"] = T("api.templates.cloud_welcome_email.subtitle")
+	data.Props["SubTitleInfo"] = T("api.templates.cloud_welcome_email.subtitle_info")
+	data.Props["Info"] = T("api.templates.cloud_welcome_email.info")
+	data.Props["Info2"] = T("api.templates.cloud_welcome_email.info2")
+	data.Props["WorkSpacePath"] = workSpacePath
+	data.Props["DNS"] = dns
+	data.Props["InviteInfo"] = T("api.templates.cloud_welcome_email.invite_info")
+	data.Props["InviteSubInfo"] = T("api.templates.cloud_welcome_email.invite_sub_info", map[string]interface{}{"WorkSpace": workSpaceName})
+	data.Props["InviteSubInfoLink"] = fmt.Sprintf("%s/signup_user_complete/?id=%s", workSpacePath, teamInviteID)
+	data.Props["AddAppsInfo"] = T("api.templates.cloud_welcome_email.add_apps_info")
+	data.Props["AddAppsSubInfo"] = T("api.templates.cloud_welcome_email.add_apps_sub_info")
+	data.Props["AppMarketPlace"] = T("api.templates.cloud_welcome_email.app_market_place")
+	data.Props["AppMarketPlaceLink"] = "https://integrations.mattermost.com/"
+	data.Props["DownloadMMInfo"] = T("api.templates.cloud_welcome_email.download_mm_info")
+	data.Props["SignInSubInfo"] = T("api.templates.cloud_welcome_email.signin_sub_info")
+	data.Props["MMApps"] = T("api.templates.cloud_welcome_email.mm_apps")
+	data.Props["SignInSubInfo2"] = T("api.templates.cloud_welcome_email.signin_sub_info2")
+	data.Props["DownloadMMAppsLink"] = "https://mattermost.com/download/"
+	data.Props["Button"] = T("api.templates.cloud_welcome_email.button")
+	data.Props["GettingStartedQuestions"] = T("api.templates.cloud_welcome_email.start_questions")
 
-	if err := es.sendMail(userEmail, subject, bodyPage.Render()); err != nil {
+	body, err := es.srv.TemplatesContainer().RenderToString("cloud_welcome_email", data)
+	if err != nil {
+		return model.NewAppError("SendCloudWelcomeEmail", "api.user.send_cloud_welcome_email.error", nil, err.Error(), http.StatusInternalServerError)
+	}
+
+	if err := es.sendMail(userEmail, subject, body); err != nil {
 		return model.NewAppError("SendCloudWelcomeEmail", "api.user.send_cloud_welcome_email.error", nil, err.Error(), http.StatusInternalServerError)
 	}
 
@@ -303,14 +339,19 @@ func (es *EmailService) sendPasswordChangeEmail(email, method, locale, siteURL s
 		map[string]interface{}{"SiteName": es.srv.Config().TeamSettings.SiteName,
 			"TeamDisplayName": es.srv.Config().TeamSettings.SiteName})
 
-	bodyPage := es.newEmailTemplate("password_change_body", locale)
-	bodyPage.Props["SiteURL"] = siteURL
-	bodyPage.Props["Title"] = T("api.templates.password_change_body.title")
-	bodyPage.Props["Info"] = T("api.templates.password_change_body.info",
+	data := es.newEmailTemplateData(locale)
+	data.Props["SiteURL"] = siteURL
+	data.Props["Title"] = T("api.templates.password_change_body.title")
+	data.Props["Info"] = T("api.templates.password_change_body.info",
 		map[string]interface{}{"TeamDisplayName": es.srv.Config().TeamSettings.SiteName, "TeamURL": siteURL, "Method": method})
-	bodyPage.Props["Warning"] = T("api.templates.email_warning")
+	data.Props["Warning"] = T("api.templates.email_warning")
 
-	if err := es.sendMail(email, subject, bodyPage.Render()); err != nil {
+	body, err := es.srv.TemplatesContainer().RenderToString("password_change_body", data)
+	if err != nil {
+		return model.NewAppError("sendPasswordChangeEmail", "api.user.send_password_change_email_and_forget.error", nil, err.Error(), http.StatusInternalServerError)
+	}
+
+	if err := es.sendMail(email, subject, body); err != nil {
 		return model.NewAppError("sendPasswordChangeEmail", "api.user.send_password_change_email_and_forget.error", nil, err.Error(), http.StatusInternalServerError)
 	}
 
@@ -323,14 +364,19 @@ func (es *EmailService) sendUserAccessTokenAddedEmail(email, locale, siteURL str
 	subject := T("api.templates.user_access_token_subject",
 		map[string]interface{}{"SiteName": es.srv.Config().TeamSettings.SiteName})
 
-	bodyPage := es.newEmailTemplate("password_change_body", locale)
-	bodyPage.Props["SiteURL"] = siteURL
-	bodyPage.Props["Title"] = T("api.templates.user_access_token_body.title")
-	bodyPage.Props["Info"] = T("api.templates.user_access_token_body.info",
+	data := es.newEmailTemplateData(locale)
+	data.Props["SiteURL"] = siteURL
+	data.Props["Title"] = T("api.templates.user_access_token_body.title")
+	data.Props["Info"] = T("api.templates.user_access_token_body.info",
 		map[string]interface{}{"SiteName": es.srv.Config().TeamSettings.SiteName, "SiteURL": siteURL})
-	bodyPage.Props["Warning"] = T("api.templates.email_warning")
+	data.Props["Warning"] = T("api.templates.email_warning")
 
-	if err := es.sendMail(email, subject, bodyPage.Render()); err != nil {
+	body, err := es.srv.TemplatesContainer().RenderToString("password_change_body", data)
+	if err != nil {
+		return model.NewAppError("sendUserAccessTokenAddedEmail", "api.user.send_user_access_token.error", nil, err.Error(), http.StatusInternalServerError)
+	}
+
+	if err := es.sendMail(email, subject, body); err != nil {
 		return model.NewAppError("sendUserAccessTokenAddedEmail", "api.user.send_user_access_token.error", nil, err.Error(), http.StatusInternalServerError)
 	}
 
@@ -345,17 +391,22 @@ func (es *EmailService) SendPasswordResetEmail(email string, token *model.Token,
 	subject := T("api.templates.reset_subject",
 		map[string]interface{}{"SiteName": es.srv.Config().TeamSettings.SiteName})
 
-	bodyPage := es.newEmailTemplate("reset_body", locale)
-	bodyPage.Props["SiteURL"] = siteURL
-	bodyPage.Props["Title"] = T("api.templates.reset_body.title")
-	bodyPage.Props["SubTitle"] = T("api.templates.reset_body.subTitle")
-	bodyPage.Props["Info"] = T("api.templates.reset_body.info")
-	bodyPage.Props["ButtonURL"] = link
-	bodyPage.Props["Button"] = T("api.templates.reset_body.button")
-	bodyPage.Props["QuestionTitle"] = T("api.templates.questions_footer.title")
-	bodyPage.Props["QuestionInfo"] = T("api.templates.questions_footer.info")
+	data := es.newEmailTemplateData(locale)
+	data.Props["SiteURL"] = siteURL
+	data.Props["Title"] = T("api.templates.reset_body.title")
+	data.Props["SubTitle"] = T("api.templates.reset_body.subTitle")
+	data.Props["Info"] = T("api.templates.reset_body.info")
+	data.Props["ButtonURL"] = link
+	data.Props["Button"] = T("api.templates.reset_body.button")
+	data.Props["QuestionTitle"] = T("api.templates.questions_footer.title")
+	data.Props["QuestionInfo"] = T("api.templates.questions_footer.info")
 
-	if err := es.sendMail(email, subject, bodyPage.Render()); err != nil {
+	body, err := es.srv.TemplatesContainer().RenderToString("reset_body", data)
+	if err != nil {
+		return false, model.NewAppError("SendPasswordReset", "api.user.send_password_reset.send.app_error", nil, "err="+err.Error(), http.StatusInternalServerError)
+	}
+
+	if err := es.sendMail(email, subject, body); err != nil {
 		return false, model.NewAppError("SendPasswordReset", "api.user.send_password_reset.send.app_error", nil, "err="+err.Error(), http.StatusInternalServerError)
 	}
 
@@ -368,19 +419,24 @@ func (es *EmailService) sendMfaChangeEmail(email string, activated bool, locale,
 	subject := T("api.templates.mfa_change_subject",
 		map[string]interface{}{"SiteName": es.srv.Config().TeamSettings.SiteName})
 
-	bodyPage := es.newEmailTemplate("mfa_change_body", locale)
-	bodyPage.Props["SiteURL"] = siteURL
+	data := es.newEmailTemplateData(locale)
+	data.Props["SiteURL"] = siteURL
 
 	if activated {
-		bodyPage.Props["Info"] = T("api.templates.mfa_activated_body.info", map[string]interface{}{"SiteURL": siteURL})
-		bodyPage.Props["Title"] = T("api.templates.mfa_activated_body.title")
+		data.Props["Info"] = T("api.templates.mfa_activated_body.info", map[string]interface{}{"SiteURL": siteURL})
+		data.Props["Title"] = T("api.templates.mfa_activated_body.title")
 	} else {
-		bodyPage.Props["Info"] = T("api.templates.mfa_deactivated_body.info", map[string]interface{}{"SiteURL": siteURL})
-		bodyPage.Props["Title"] = T("api.templates.mfa_deactivated_body.title")
+		data.Props["Info"] = T("api.templates.mfa_deactivated_body.info", map[string]interface{}{"SiteURL": siteURL})
+		data.Props["Title"] = T("api.templates.mfa_deactivated_body.title")
 	}
-	bodyPage.Props["Warning"] = T("api.templates.email_warning")
+	data.Props["Warning"] = T("api.templates.email_warning")
 
-	if err := es.sendMail(email, subject, bodyPage.Render()); err != nil {
+	body, err := es.srv.TemplatesContainer().RenderToString("mfa_change_body", data)
+	if err != nil {
+		return model.NewAppError("SendMfaChangeEmail", "api.user.send_mfa_change_email.error", nil, err.Error(), http.StatusInternalServerError)
+	}
+
+	if err := es.sendMail(email, subject, body); err != nil {
 		return model.NewAppError("SendMfaChangeEmail", "api.user.send_mfa_change_email.error", nil, err.Error(), http.StatusInternalServerError)
 	}
 
@@ -411,34 +467,39 @@ func (es *EmailService) SendInviteEmails(team *model.Team, senderName string, se
 					"TeamDisplayName": team.DisplayName,
 					"SiteName":        es.srv.Config().TeamSettings.SiteName})
 
-			bodyPage := es.newEmailTemplate("invite_body", "")
-			bodyPage.Props["SiteURL"] = siteURL
-			bodyPage.Props["Title"] = i18n.T("api.templates.invite_body.title", map[string]interface{}{"SenderName": senderName, "TeamDisplayName": team.DisplayName})
-			bodyPage.Props["SubTitle"] = i18n.T("api.templates.invite_body.subTitle")
-			bodyPage.Props["Button"] = i18n.T("api.templates.invite_body.button")
-			bodyPage.Props["SenderName"] = senderName
-			bodyPage.Props["InviteFooterTitle"] = i18n.T("api.templates.invite_body_footer.title")
-			bodyPage.Props["InviteFooterInfo"] = i18n.T("api.templates.invite_body_footer.info")
-			bodyPage.Props["InviteFooterLearnMore"] = i18n.T("api.templates.invite_body_footer.learn_more")
+			data := es.newEmailTemplateData("")
+			data.Props["SiteURL"] = siteURL
+			data.Props["Title"] = i18n.T("api.templates.invite_body.title", map[string]interface{}{"SenderName": senderName, "TeamDisplayName": team.DisplayName})
+			data.Props["SubTitle"] = i18n.T("api.templates.invite_body.subTitle")
+			data.Props["Button"] = i18n.T("api.templates.invite_body.button")
+			data.Props["SenderName"] = senderName
+			data.Props["InviteFooterTitle"] = i18n.T("api.templates.invite_body_footer.title")
+			data.Props["InviteFooterInfo"] = i18n.T("api.templates.invite_body_footer.info")
+			data.Props["InviteFooterLearnMore"] = i18n.T("api.templates.invite_body_footer.learn_more")
 
 			token := model.NewToken(
 				TokenTypeTeamInvitation,
 				model.MapToJson(map[string]string{"teamId": team.Id, "email": invite}),
 			)
 
-			props := make(map[string]string)
-			props["email"] = invite
-			props["display_name"] = team.DisplayName
-			props["name"] = team.Name
-			data := model.MapToJson(props)
+			tokenProps := make(map[string]string)
+			tokenProps["email"] = invite
+			tokenProps["display_name"] = team.DisplayName
+			tokenProps["name"] = team.Name
+			tokenData := model.MapToJson(tokenProps)
 
 			if err := es.srv.Store.Token().Save(token); err != nil {
 				mlog.Error("Failed to send invite email successfully ", mlog.Err(err))
 				continue
 			}
-			bodyPage.Props["ButtonURL"] = fmt.Sprintf("%s/signup_user_complete/?d=%s&t=%s", siteURL, url.QueryEscape(data), url.QueryEscape(token.Token))
+			data.Props["ButtonURL"] = fmt.Sprintf("%s/signup_user_complete/?d=%s&t=%s", siteURL, url.QueryEscape(tokenData), url.QueryEscape(token.Token))
 
-			if err := es.sendMail(invite, subject, bodyPage.Render()); err != nil {
+			body, err := es.srv.TemplatesContainer().RenderToString("invite_body", data)
+			if err != nil {
+				mlog.Error("Failed to send invite email successfully ", mlog.Err(err))
+			}
+
+			if err := es.sendMail(invite, subject, body); err != nil {
 				mlog.Error("Failed to send invite email successfully ", mlog.Err(err))
 			}
 		}
@@ -470,19 +531,19 @@ func (es *EmailService) sendGuestInviteEmails(team *model.Team, channels []*mode
 					"TeamDisplayName": team.DisplayName,
 					"SiteName":        es.srv.Config().TeamSettings.SiteName})
 
-			bodyPage := es.newEmailTemplate("invite_body", "")
-			bodyPage.Props["SiteURL"] = siteURL
-			bodyPage.Props["Title"] = i18n.T("api.templates.invite_body.title", map[string]interface{}{"SenderName": senderName, "TeamDisplayName": team.DisplayName})
-			bodyPage.Props["SubTitle"] = i18n.T("api.templates.invite_body_guest.subTitle")
-			bodyPage.Props["Button"] = i18n.T("api.templates.invite_body.button")
-			bodyPage.Props["SenderName"] = senderName
-			bodyPage.Props["Message"] = ""
+			data := es.newEmailTemplateData("")
+			data.Props["SiteURL"] = siteURL
+			data.Props["Title"] = i18n.T("api.templates.invite_body.title", map[string]interface{}{"SenderName": senderName, "TeamDisplayName": team.DisplayName})
+			data.Props["SubTitle"] = i18n.T("api.templates.invite_body_guest.subTitle")
+			data.Props["Button"] = i18n.T("api.templates.invite_body.button")
+			data.Props["SenderName"] = senderName
+			data.Props["Message"] = ""
 			if message != "" {
-				bodyPage.Props["Message"] = message
+				data.Props["Message"] = message
 			}
-			bodyPage.Props["InviteFooterTitle"] = i18n.T("api.templates.invite_body_footer.title")
-			bodyPage.Props["InviteFooterInfo"] = i18n.T("api.templates.invite_body_footer.info")
-			bodyPage.Props["InviteFooterLearnMore"] = i18n.T("api.templates.invite_body_footer.learn_more")
+			data.Props["InviteFooterTitle"] = i18n.T("api.templates.invite_body_footer.title")
+			data.Props["InviteFooterInfo"] = i18n.T("api.templates.invite_body_footer.info")
+			data.Props["InviteFooterLearnMore"] = i18n.T("api.templates.invite_body_footer.learn_more")
 
 			channelIDs := []string{}
 			for _, channel := range channels {
@@ -499,20 +560,20 @@ func (es *EmailService) sendGuestInviteEmails(team *model.Team, channels []*mode
 				}),
 			)
 
-			props := make(map[string]string)
-			props["email"] = invite
-			props["display_name"] = team.DisplayName
-			props["name"] = team.Name
-			data := model.MapToJson(props)
+			tokenProps := make(map[string]string)
+			tokenProps["email"] = invite
+			tokenProps["display_name"] = team.DisplayName
+			tokenProps["name"] = team.Name
+			tokenData := model.MapToJson(tokenProps)
 
 			if err := es.srv.Store.Token().Save(token); err != nil {
 				mlog.Error("Failed to send invite email successfully ", mlog.Err(err))
 				continue
 			}
-			bodyPage.Props["ButtonURL"] = fmt.Sprintf("%s/signup_user_complete/?d=%s&t=%s", siteURL, url.QueryEscape(data), url.QueryEscape(token.Token))
+			data.Props["ButtonURL"] = fmt.Sprintf("%s/signup_user_complete/?d=%s&t=%s", siteURL, url.QueryEscape(tokenData), url.QueryEscape(token.Token))
 
 			if !*es.srv.Config().EmailSettings.SendEmailNotifications {
-				mlog.Info("sending invitation ", mlog.String("to", invite), mlog.String("link", bodyPage.Props["Link"].(string)))
+				mlog.Info("sending invitation ", mlog.String("to", invite), mlog.String("link", data.Props["ButtomURL"].(string)))
 			}
 
 			embeddedFiles := make(map[string]io.Reader)
@@ -524,7 +585,12 @@ func (es *EmailService) sendGuestInviteEmails(team *model.Team, channels []*mode
 				}
 			}
 
-			if nErr := es.sendMailWithEmbeddedFiles(invite, subject, bodyPage.Render(), embeddedFiles); nErr != nil {
+			body, err := es.srv.TemplatesContainer().RenderToString("invite_body", data)
+			if err != nil {
+				mlog.Error("Failed to send invite email successfully", mlog.Err(err))
+			}
+
+			if nErr := es.sendMailWithEmbeddedFiles(invite, subject, body, embeddedFiles); nErr != nil {
 				mlog.Error("Failed to send invite email successfully", mlog.Err(nErr))
 			}
 		}
@@ -532,32 +598,32 @@ func (es *EmailService) sendGuestInviteEmails(team *model.Team, channels []*mode
 	return nil
 }
 
-func (es *EmailService) newEmailTemplate(name, locale string) *utils.HTMLTemplate {
-	t := utils.NewHTMLTemplate(es.srv.HTMLTemplates(), name)
-
+func (es *EmailService) newEmailTemplateData(locale string) templates.Data {
 	var localT i18n.TranslateFunc
 	if locale != "" {
 		localT = i18n.GetUserTranslations(locale)
 	} else {
 		localT = i18n.T
 	}
-
-	t.Props["Footer"] = localT("api.templates.email_footer")
-	t.Props["FooterV2"] = localT("api.templates.email_footer_v2")
+	organization := ""
 
 	if *es.srv.Config().EmailSettings.FeedbackOrganization != "" {
-		t.Props["Organization"] = localT("api.templates.email_organization") + *es.srv.Config().EmailSettings.FeedbackOrganization
-	} else {
-		t.Props["Organization"] = ""
+		organization = localT("api.templates.email_organization") + *es.srv.Config().EmailSettings.FeedbackOrganization
 	}
 
-	t.Props["EmailInfo1"] = localT("api.templates.email_info1")
-	t.Props["EmailInfo2"] = localT("api.templates.email_info2")
-	t.Props["EmailInfo3"] = localT("api.templates.email_info3",
-		map[string]interface{}{"SiteName": es.srv.Config().TeamSettings.SiteName})
-	t.Props["SupportEmail"] = *es.srv.Config().SupportSettings.SupportEmail
-
-	return t
+	return templates.Data{
+		Props: map[string]interface{}{
+			"EmailInfo1": localT("api.templates.email_info1"),
+			"EmailInfo2": localT("api.templates.email_info2"),
+			"EmailInfo3": localT("api.templates.email_info3",
+				map[string]interface{}{"SiteName": es.srv.Config().TeamSettings.SiteName}),
+			"SupportEmail": *es.srv.Config().SupportSettings.SupportEmail,
+			"Footer":       localT("api.templates.email_footer"),
+			"FooterV2":     localT("api.templates.email_footer_v2"),
+			"Organization": organization,
+		},
+		HTML: map[string]template.HTML{},
+	}
 }
 
 func (es *EmailService) SendDeactivateAccountEmail(email string, locale, siteURL string) *model.AppError {
@@ -569,14 +635,19 @@ func (es *EmailService) SendDeactivateAccountEmail(email string, locale, siteURL
 		map[string]interface{}{"SiteName": es.srv.Config().TeamSettings.SiteName,
 			"ServerURL": serverURL})
 
-	bodyPage := es.newEmailTemplate("deactivate_body", locale)
-	bodyPage.Props["SiteURL"] = siteURL
-	bodyPage.Props["Title"] = T("api.templates.deactivate_body.title", map[string]interface{}{"ServerURL": serverURL})
-	bodyPage.Props["Info"] = T("api.templates.deactivate_body.info",
+	data := es.newEmailTemplateData(locale)
+	data.Props["SiteURL"] = siteURL
+	data.Props["Title"] = T("api.templates.deactivate_body.title", map[string]interface{}{"ServerURL": serverURL})
+	data.Props["Info"] = T("api.templates.deactivate_body.info",
 		map[string]interface{}{"SiteURL": siteURL})
-	bodyPage.Props["Warning"] = T("api.templates.deactivate_body.warning")
+	data.Props["Warning"] = T("api.templates.deactivate_body.warning")
 
-	if err := es.sendMail(email, subject, bodyPage.Render()); err != nil {
+	body, err := es.srv.TemplatesContainer().RenderToString("deactivate_body", data)
+	if err != nil {
+		return model.NewAppError("SendDeactivateEmail", "api.user.send_deactivate_email_and_forget.failed.error", nil, err.Error(), http.StatusInternalServerError)
+	}
+
+	if err := es.sendMail(email, subject, body); err != nil {
 		return model.NewAppError("SendDeactivateEmail", "api.user.send_deactivate_email_and_forget.failed.error", nil, err.Error(), http.StatusInternalServerError)
 	}
 
@@ -595,13 +666,18 @@ func (es *EmailService) SendRemoveExpiredLicenseEmail(email string, locale, site
 	subject := T("api.templates.remove_expired_license.subject",
 		map[string]interface{}{"SiteName": es.srv.Config().TeamSettings.SiteName})
 
-	bodyPage := es.newEmailTemplate("remove_expired_license", locale)
-	bodyPage.Props["SiteURL"] = siteURL
-	bodyPage.Props["Title"] = T("api.templates.remove_expired_license.body.title")
-	bodyPage.Props["Link"] = renewalLink
-	bodyPage.Props["LinkButton"] = T("api.templates.remove_expired_license.body.renew_button")
+	data := es.newEmailTemplateData(locale)
+	data.Props["SiteURL"] = siteURL
+	data.Props["Title"] = T("api.templates.remove_expired_license.body.title")
+	data.Props["Link"] = renewalLink
+	data.Props["LinkButton"] = T("api.templates.remove_expired_license.body.renew_button")
 
-	if err := es.sendMail(email, subject, bodyPage.Render()); err != nil {
+	body, nErr := es.srv.TemplatesContainer().RenderToString("remove_expired_license", data)
+	if nErr != nil {
+		return model.NewAppError("SendRemoveExpiredLicenseEmail", "api.license.remove_expired_license.failed.error", nil, nErr.Error(), http.StatusInternalServerError)
+	}
+
+	if err := es.sendMail(email, subject, body); err != nil {
 		return model.NewAppError("SendRemoveExpiredLicenseEmail", "api.license.remove_expired_license.failed.error", nil, err.Error(), http.StatusInternalServerError)
 	}
 
@@ -667,17 +743,22 @@ func (es *EmailService) SendAtUserLimitWarningEmail(email string, locale string,
 
 	subject := T("api.templates.at_limit_subject")
 
-	bodyPage := es.newEmailTemplate("reached_user_limit_body", locale)
-	bodyPage.Props["SiteURL"] = siteURL
-	bodyPage.Props["Title"] = T("api.templates.at_limit_title")
-	bodyPage.Props["Info1"] = T("api.templates.at_limit_info1")
-	bodyPage.Props["Info2"] = T("api.templates.at_limit_info2")
-	bodyPage.Props["Button"] = T("api.templates.upgrade_mattermost_cloud")
-	bodyPage.Props["EmailUs"] = T("api.templates.email_us_anytime_at")
+	data := es.newEmailTemplateData(locale)
+	data.Props["SiteURL"] = siteURL
+	data.Props["Title"] = T("api.templates.at_limit_title")
+	data.Props["Info1"] = T("api.templates.at_limit_info1")
+	data.Props["Info2"] = T("api.templates.at_limit_info2")
+	data.Props["Button"] = T("api.templates.upgrade_mattermost_cloud")
+	data.Props["EmailUs"] = T("api.templates.email_us_anytime_at")
 
-	bodyPage.Props["Footer"] = T("api.templates.copyright")
+	data.Props["Footer"] = T("api.templates.copyright")
 
-	if err := es.sendMail(email, subject, bodyPage.Render()); err != nil {
+	body, err := es.srv.TemplatesContainer().RenderToString("reached_user_limit_body", data)
+	if err != nil {
+		return false, model.NewAppError("SendAtUserLimitWarningEmail", "api.user.send_password_reset.send.app_error", nil, "err="+err.Error(), http.StatusInternalServerError)
+	}
+
+	if err := es.sendMail(email, subject, body); err != nil {
 		return false, model.NewAppError("SendAtUserLimitWarningEmail", "api.user.send_password_reset.send.app_error", nil, "err="+err.Error(), http.StatusInternalServerError)
 	}
 
@@ -688,25 +769,30 @@ func (es *EmailService) SendAtUserLimitWarningEmail(email string, locale string,
 func (es *EmailService) SendUpgradeEmail(user, email, locale, siteURL, action string) (bool, *model.AppError) {
 	T := i18n.GetUserTranslations(locale)
 
-	bodyPage := es.newEmailTemplate("cloud_upgrade_request_email", locale)
+	subject := T("api.templates.upgrade_request_subject")
+
+	data := es.newEmailTemplateData(locale)
+	data.Props["Info5"] = T("api.templates.at_limit_info5")
+	data.Props["BillingPath"] = "admin_console/billing/subscription"
+	data.Props["SiteURL"] = siteURL
+	data.Props["Button"] = T("api.templates.upgrade_mattermost_cloud")
+	data.Props["EmailUs"] = T("api.templates.email_us_anytime_at")
+	data.Props["Footer"] = T("api.templates.copyright")
 
 	if action == model.InviteLimitation {
-		bodyPage.Props["Title"] = T("api.templates.upgrade_request_title", map[string]interface{}{"UserName": user})
-		bodyPage.Props["Info4"] = T("api.templates.upgrade_request_info4")
+		data.Props["Title"] = T("api.templates.upgrade_request_title", map[string]interface{}{"UserName": user})
+		data.Props["Info4"] = T("api.templates.upgrade_request_info4")
 	} else {
-		bodyPage.Props["Title"] = T("api.templates.upgrade_request_title2")
-		bodyPage.Props["Info4"] = T("api.templates.upgrade_request_info4_2")
+		data.Props["Title"] = T("api.templates.upgrade_request_title2")
+		data.Props["Info4"] = T("api.templates.upgrade_request_info4_2")
 	}
 
-	subject := T("api.templates.upgrade_request_subject")
-	bodyPage.Props["Info5"] = T("api.templates.at_limit_info5")
-	bodyPage.Props["BillingPath"] = "admin_console/billing/subscription"
-	bodyPage.Props["SiteURL"] = siteURL
-	bodyPage.Props["Button"] = T("api.templates.upgrade_mattermost_cloud")
-	bodyPage.Props["EmailUs"] = T("api.templates.email_us_anytime_at")
-	bodyPage.Props["Footer"] = T("api.templates.copyright")
+	body, err := es.srv.TemplatesContainer().RenderToString("cloud_upgrade_request_email", data)
+	if err != nil {
+		return false, model.NewAppError("SendUpgradeEmail", "api.user.send_upgrade_request_email.error", nil, err.Error(), http.StatusInternalServerError)
+	}
 
-	if err := es.sendMail(email, subject, bodyPage.Render()); err != nil {
+	if err := es.sendMail(email, subject, body); err != nil {
 		return false, model.NewAppError("SendUpgradeEmail", "api.user.send_upgrade_request_email.error", nil, err.Error(), http.StatusInternalServerError)
 	}
 
@@ -718,17 +804,22 @@ func (es *EmailService) SendOverUserLimitWarningEmail(email string, locale strin
 
 	subject := T("api.templates.over_limit_subject")
 
-	bodyPage := es.newEmailTemplate("reached_user_limit_body", locale)
-	bodyPage.Props["SiteURL"] = siteURL
-	bodyPage.Props["Title"] = T("api.templates.over_limit_title")
-	bodyPage.Props["Info1"] = T("api.templates.over_limit_info1")
-	bodyPage.Props["Info2"] = T("api.templates.over_limit_info2")
-	bodyPage.Props["Button"] = T("api.templates.upgrade_mattermost_cloud")
-	bodyPage.Props["EmailUs"] = T("api.templates.email_us_anytime_at")
+	data := es.newEmailTemplateData(locale)
+	data.Props["SiteURL"] = siteURL
+	data.Props["Title"] = T("api.templates.over_limit_title")
+	data.Props["Info1"] = T("api.templates.over_limit_info1")
+	data.Props["Info2"] = T("api.templates.over_limit_info2")
+	data.Props["Button"] = T("api.templates.upgrade_mattermost_cloud")
+	data.Props["EmailUs"] = T("api.templates.email_us_anytime_at")
 
-	bodyPage.Props["Footer"] = T("api.templates.copyright")
+	data.Props["Footer"] = T("api.templates.copyright")
 
-	if err := es.sendMail(email, subject, bodyPage.Render()); err != nil {
+	body, err := es.srv.TemplatesContainer().RenderToString("reached_user_limit_body", data)
+	if err != nil {
+		return false, model.NewAppError("SendOverUserLimitWarningEmail", "api.user.send_password_reset.send.app_error", nil, "err="+err.Error(), http.StatusInternalServerError)
+	}
+
+	if err := es.sendMail(email, subject, body); err != nil {
 		return false, model.NewAppError("SendOverUserLimitWarningEmail", "api.user.send_password_reset.send.app_error", nil, "err="+err.Error(), http.StatusInternalServerError)
 	}
 
@@ -740,20 +831,25 @@ func (es *EmailService) SendOverUserLimitThirtyDayWarningEmail(email string, loc
 
 	subject := T("api.templates.over_limit_30_days_subject")
 
-	bodyPage := es.newEmailTemplate("over_user_limit_30_days_body", locale)
-	bodyPage.Props["SiteURL"] = siteURL
-	bodyPage.Props["Title"] = T("api.templates.over_limit_30_days_title")
-	bodyPage.Props["Info1"] = T("api.templates.over_limit_30_days_info1")
-	bodyPage.Props["Info2"] = T("api.templates.over_limit_30_days_info2")
-	bodyPage.Props["Info2Item1"] = T("api.templates.over_limit_30_days_info2_item1")
-	bodyPage.Props["Info2Item2"] = T("api.templates.over_limit_30_days_info2_item2")
-	bodyPage.Props["Info2Item3"] = T("api.templates.over_limit_30_days_info2_item3")
-	bodyPage.Props["Button"] = T("api.templates.over_limit_fix_now")
-	bodyPage.Props["EmailUs"] = T("api.templates.email_us_anytime_at")
+	data := es.newEmailTemplateData(locale)
+	data.Props["SiteURL"] = siteURL
+	data.Props["Title"] = T("api.templates.over_limit_30_days_title")
+	data.Props["Info1"] = T("api.templates.over_limit_30_days_info1")
+	data.Props["Info2"] = T("api.templates.over_limit_30_days_info2")
+	data.Props["Info2Item1"] = T("api.templates.over_limit_30_days_info2_item1")
+	data.Props["Info2Item2"] = T("api.templates.over_limit_30_days_info2_item2")
+	data.Props["Info2Item3"] = T("api.templates.over_limit_30_days_info2_item3")
+	data.Props["Button"] = T("api.templates.over_limit_fix_now")
+	data.Props["EmailUs"] = T("api.templates.email_us_anytime_at")
 
-	bodyPage.Props["Footer"] = T("api.templates.copyright")
+	data.Props["Footer"] = T("api.templates.copyright")
 
-	if err := es.sendMail(email, subject, bodyPage.Render()); err != nil {
+	body, err := es.srv.TemplatesContainer().RenderToString("over_user_limit_30_days_body", data)
+	if err != nil {
+		return false, model.NewAppError("SendOverUserLimitWarningEmail", "api.user.send_password_reset.send.app_error", nil, "err="+err.Error(), http.StatusInternalServerError)
+	}
+
+	if err := es.sendMail(email, subject, body); err != nil {
 		return false, model.NewAppError("SendOverUserLimitWarningEmail", "api.user.send_password_reset.send.app_error", nil, "err="+err.Error(), http.StatusInternalServerError)
 	}
 
@@ -765,19 +861,24 @@ func (es *EmailService) SendOverUserLimitNinetyDayWarningEmail(email string, loc
 
 	subject := T("api.templates.over_limit_90_days_subject")
 
-	bodyPage := es.newEmailTemplate("over_user_limit_90_days_body", locale)
-	bodyPage.Props["SiteURL"] = siteURL
-	bodyPage.Props["Title"] = T("api.templates.over_limit_90_days_title")
-	bodyPage.Props["Info1"] = T("api.templates.over_limit_90_days_info1", map[string]interface{}{"OverLimitDate": overLimitDate})
-	bodyPage.Props["Info2"] = T("api.templates.over_limit_90_days_info2")
-	bodyPage.Props["Info3"] = T("api.templates.over_limit_90_days_info3")
-	bodyPage.Props["Info4"] = T("api.templates.over_limit_90_days_info4")
-	bodyPage.Props["Button"] = T("api.templates.over_limit_fix_now")
-	bodyPage.Props["EmailUs"] = T("api.templates.email_us_anytime_at")
+	data := es.newEmailTemplateData(locale)
+	data.Props["SiteURL"] = siteURL
+	data.Props["Title"] = T("api.templates.over_limit_90_days_title")
+	data.Props["Info1"] = T("api.templates.over_limit_90_days_info1", map[string]interface{}{"OverLimitDate": overLimitDate})
+	data.Props["Info2"] = T("api.templates.over_limit_90_days_info2")
+	data.Props["Info3"] = T("api.templates.over_limit_90_days_info3")
+	data.Props["Info4"] = T("api.templates.over_limit_90_days_info4")
+	data.Props["Button"] = T("api.templates.over_limit_fix_now")
+	data.Props["EmailUs"] = T("api.templates.email_us_anytime_at")
 
-	bodyPage.Props["Footer"] = T("api.templates.copyright")
+	data.Props["Footer"] = T("api.templates.copyright")
 
-	if err := es.sendMail(email, subject, bodyPage.Render()); err != nil {
+	body, err := es.srv.TemplatesContainer().RenderToString("over_user_limit_90_days_body", data)
+	if err != nil {
+		return false, model.NewAppError("SendOverUserLimitWarningEmail", "api.user.send_password_reset.send.app_error", nil, "err="+err.Error(), http.StatusInternalServerError)
+	}
+
+	if err := es.sendMail(email, subject, body); err != nil {
 		return false, model.NewAppError("SendOverUserLimitWarningEmail", "api.user.send_password_reset.send.app_error", nil, "err="+err.Error(), http.StatusInternalServerError)
 	}
 
@@ -789,17 +890,22 @@ func (es *EmailService) SendOverUserLimitWorkspaceSuspendedWarningEmail(email st
 
 	subject := T("api.templates.over_limit_suspended_subject")
 
-	bodyPage := es.newEmailTemplate("over_user_limit_workspace_suspended_body", locale)
-	bodyPage.Props["SiteURL"] = siteURL
-	bodyPage.Props["Title"] = T("api.templates.over_limit_suspended_title")
-	bodyPage.Props["Info1"] = T("api.templates.over_limit_suspended_info1")
-	bodyPage.Props["Info2"] = T("api.templates.over_limit_suspended_info2")
-	bodyPage.Props["Button"] = T("api.templates.over_limit_suspended_contact_support")
-	bodyPage.Props["EmailUs"] = T("api.templates.email_us_anytime_at")
+	data := es.newEmailTemplateData(locale)
+	data.Props["SiteURL"] = siteURL
+	data.Props["Title"] = T("api.templates.over_limit_suspended_title")
+	data.Props["Info1"] = T("api.templates.over_limit_suspended_info1")
+	data.Props["Info2"] = T("api.templates.over_limit_suspended_info2")
+	data.Props["Button"] = T("api.templates.over_limit_suspended_contact_support")
+	data.Props["EmailUs"] = T("api.templates.email_us_anytime_at")
 
-	bodyPage.Props["Footer"] = T("api.templates.copyright")
+	data.Props["Footer"] = T("api.templates.copyright")
 
-	if err := es.sendMail(email, subject, bodyPage.Render()); err != nil {
+	body, err := es.srv.TemplatesContainer().RenderToString("over_user_limit_workspace_suspended_body", data)
+	if err != nil {
+		return false, model.NewAppError("SendOverUserLimitWarningEmail", "api.user.send_password_reset.send.app_error", nil, "err="+err.Error(), http.StatusInternalServerError)
+	}
+
+	if err := es.sendMail(email, subject, body); err != nil {
 		return false, model.NewAppError("SendOverUserLimitWarningEmail", "api.user.send_password_reset.send.app_error", nil, "err="+err.Error(), http.StatusInternalServerError)
 	}
 
@@ -811,16 +917,21 @@ func (es *EmailService) SendOverUserFourteenDayWarningEmail(email string, locale
 
 	subject := T("api.templates.over_limit_14_days_subject")
 
-	bodyPage := es.newEmailTemplate("over_user_limit_7_days_body", locale)
-	bodyPage.Props["SiteURL"] = siteURL
-	bodyPage.Props["Title"] = T("api.templates.over_limit_14_days_title")
-	bodyPage.Props["Info1"] = T("api.templates.over_limit_14_days_info1", map[string]interface{}{"OverLimitDate": overLimitDate})
-	bodyPage.Props["Button"] = T("api.templates.over_limit_fix_now")
-	bodyPage.Props["EmailUs"] = T("api.templates.email_us_anytime_at")
+	data := es.newEmailTemplateData(locale)
+	data.Props["SiteURL"] = siteURL
+	data.Props["Title"] = T("api.templates.over_limit_14_days_title")
+	data.Props["Info1"] = T("api.templates.over_limit_14_days_info1", map[string]interface{}{"OverLimitDate": overLimitDate})
+	data.Props["Button"] = T("api.templates.over_limit_fix_now")
+	data.Props["EmailUs"] = T("api.templates.email_us_anytime_at")
 
-	bodyPage.Props["Footer"] = T("api.templates.copyright")
+	data.Props["Footer"] = T("api.templates.copyright")
 
-	if err := es.sendMail(email, subject, bodyPage.Render()); err != nil {
+	body, err := es.srv.TemplatesContainer().RenderToString("over_user_limit_7_days_body", data)
+	if err != nil {
+		return false, model.NewAppError("SendOverUserLimitWarningEmail", "api.user.send_password_reset.send.app_error", nil, "err="+err.Error(), http.StatusInternalServerError)
+	}
+
+	if err := es.sendMail(email, subject, body); err != nil {
 		return false, model.NewAppError("SendOverUserLimitWarningEmail", "api.user.send_password_reset.send.app_error", nil, "err="+err.Error(), http.StatusInternalServerError)
 	}
 
@@ -832,16 +943,21 @@ func (es *EmailService) SendOverUserSevenDayWarningEmail(email string, locale st
 
 	subject := T("api.templates.over_limit_7_days_subject")
 
-	bodyPage := es.newEmailTemplate("over_user_limit_7_days_body", locale)
-	bodyPage.Props["SiteURL"] = siteURL
-	bodyPage.Props["Title"] = T("api.templates.over_limit_7_days_title")
-	bodyPage.Props["Info1"] = T("api.templates.over_limit_7_days_info1")
-	bodyPage.Props["Button"] = T("api.templates.over_limit_fix_now")
-	bodyPage.Props["EmailUs"] = T("api.templates.email_us_anytime_at")
+	data := es.newEmailTemplateData(locale)
+	data.Props["SiteURL"] = siteURL
+	data.Props["Title"] = T("api.templates.over_limit_7_days_title")
+	data.Props["Info1"] = T("api.templates.over_limit_7_days_info1")
+	data.Props["Button"] = T("api.templates.over_limit_fix_now")
+	data.Props["EmailUs"] = T("api.templates.email_us_anytime_at")
 
-	bodyPage.Props["Footer"] = T("api.templates.copyright")
+	data.Props["Footer"] = T("api.templates.copyright")
 
-	if err := es.sendMail(email, subject, bodyPage.Render()); err != nil {
+	body, err := es.srv.TemplatesContainer().RenderToString("over_user_limit_7_days_body", data)
+	if err != nil {
+		return false, model.NewAppError("SendOverUserLimitWarningEmail", "api.user.send_password_reset.send.app_error", nil, "err="+err.Error(), http.StatusInternalServerError)
+	}
+
+	if err := es.sendMail(email, subject, body); err != nil {
 		return false, model.NewAppError("SendOverUserLimitWarningEmail", "api.user.send_password_reset.send.app_error", nil, "err="+err.Error(), http.StatusInternalServerError)
 	}
 
@@ -852,15 +968,20 @@ func (es *EmailService) SendSuspensionEmailToSupport(email string, installationI
 	// Localization not needed
 
 	subject := fmt.Sprintf("Cloud Installation %s Scheduled Suspension", installationID)
-	bodyPage := es.newEmailTemplate("over_user_limit_support_body", "en")
-	bodyPage.Props["CustomerID"] = customerID
-	bodyPage.Props["SiteURL"] = siteURL
-	bodyPage.Props["SubscriptionID"] = subscriptionID
-	bodyPage.Props["InstallationID"] = installationID
-	bodyPage.Props["SuspensionDate"] = time.Now().AddDate(0, 0, 61).Format("2006-01-02")
-	bodyPage.Props["UserCount"] = userCount
+	data := es.newEmailTemplateData("en")
+	data.Props["CustomerID"] = customerID
+	data.Props["SiteURL"] = siteURL
+	data.Props["SubscriptionID"] = subscriptionID
+	data.Props["InstallationID"] = installationID
+	data.Props["SuspensionDate"] = time.Now().AddDate(0, 0, 61).Format("2006-01-02")
+	data.Props["UserCount"] = userCount
 
-	if err := es.sendMail(email, subject, bodyPage.Render()); err != nil {
+	body, err := es.srv.TemplatesContainer().RenderToString("over_user_limit_support_body", data)
+	if err != nil {
+		return false, model.NewAppError("SendOverUserLimitWarningEmail", "api.user.send_password_reset.send.app_error", nil, "err="+err.Error(), http.StatusInternalServerError)
+	}
+
+	if err := es.sendMail(email, subject, body); err != nil {
 		return false, model.NewAppError("SendOverUserLimitWarningEmail", "api.user.send_password_reset.send.app_error", nil, "err="+err.Error(), http.StatusInternalServerError)
 	}
 
@@ -872,20 +993,25 @@ func (es *EmailService) SendPaymentFailedEmail(email string, locale string, fail
 
 	subject := T("api.templates.payment_failed.subject")
 
-	bodyPage := es.newEmailTemplate("payment_failed_body", locale)
-	bodyPage.Props["SiteURL"] = siteURL
-	bodyPage.Props["Title"] = T("api.templates.payment_failed.title")
-	bodyPage.Props["Info1"] = T("api.templates.payment_failed.info1", map[string]interface{}{"CardBrand": failedPayment.CardBrand, "LastFour": failedPayment.LastFour})
-	bodyPage.Props["Info2"] = T("api.templates.payment_failed.info2")
-	bodyPage.Props["Info3"] = T("api.templates.payment_failed.info3")
-	bodyPage.Props["Button"] = T("api.templates.over_limit_fix_now")
-	bodyPage.Props["EmailUs"] = T("api.templates.email_us_anytime_at")
+	data := es.newEmailTemplateData(locale)
+	data.Props["SiteURL"] = siteURL
+	data.Props["Title"] = T("api.templates.payment_failed.title")
+	data.Props["Info1"] = T("api.templates.payment_failed.info1", map[string]interface{}{"CardBrand": failedPayment.CardBrand, "LastFour": failedPayment.LastFour})
+	data.Props["Info2"] = T("api.templates.payment_failed.info2")
+	data.Props["Info3"] = T("api.templates.payment_failed.info3")
+	data.Props["Button"] = T("api.templates.over_limit_fix_now")
+	data.Props["EmailUs"] = T("api.templates.email_us_anytime_at")
 
-	bodyPage.Props["Footer"] = T("api.templates.copyright")
+	data.Props["Footer"] = T("api.templates.copyright")
 
-	bodyPage.Props["FailedReason"] = failedPayment.FailureMessage
+	data.Props["FailedReason"] = failedPayment.FailureMessage
 
-	if err := es.sendMail(email, subject, bodyPage.Render()); err != nil {
+	body, err := es.srv.TemplatesContainer().RenderToString("payment_failed_body", data)
+	if err != nil {
+		return false, model.NewAppError("SendPaymentFailedEmail", "api.user.send_password_reset.send.app_error", nil, "err="+err.Error(), http.StatusInternalServerError)
+	}
+
+	if err := es.sendMail(email, subject, body); err != nil {
 		return false, model.NewAppError("SendPaymentFailedEmail", "api.user.send_password_reset.send.app_error", nil, "err="+err.Error(), http.StatusInternalServerError)
 	}
 
@@ -897,17 +1023,22 @@ func (es *EmailService) SendNoCardPaymentFailedEmail(email string, locale string
 
 	subject := T("api.templates.payment_failed_no_card.subject")
 
-	bodyPage := es.newEmailTemplate("payment_failed_no_card_body", locale)
-	bodyPage.Props["SiteURL"] = siteURL
-	bodyPage.Props["Title"] = T("api.templates.payment_failed_no_card.title")
-	bodyPage.Props["Info1"] = T("api.templates.payment_failed_no_card.info1")
-	bodyPage.Props["Info3"] = T("api.templates.payment_failed_no_card.info3")
-	bodyPage.Props["Button"] = T("api.templates.payment_failed_no_card.button")
-	bodyPage.Props["EmailUs"] = T("api.templates.email_us_anytime_at")
+	data := es.newEmailTemplateData(locale)
+	data.Props["SiteURL"] = siteURL
+	data.Props["Title"] = T("api.templates.payment_failed_no_card.title")
+	data.Props["Info1"] = T("api.templates.payment_failed_no_card.info1")
+	data.Props["Info3"] = T("api.templates.payment_failed_no_card.info3")
+	data.Props["Button"] = T("api.templates.payment_failed_no_card.button")
+	data.Props["EmailUs"] = T("api.templates.email_us_anytime_at")
 
-	bodyPage.Props["Footer"] = T("api.templates.copyright")
+	data.Props["Footer"] = T("api.templates.copyright")
 
-	if err := es.sendMail(email, subject, bodyPage.Render()); err != nil {
+	body, err := es.srv.TemplatesContainer().RenderToString("payment_failed_no_card_body", data)
+	if err != nil {
+		return model.NewAppError("SendPaymentFailedEmail", "api.user.send_password_reset.send.app_error", nil, "err="+err.Error(), http.StatusInternalServerError)
+	}
+
+	if err := es.sendMail(email, subject, body); err != nil {
 		return model.NewAppError("SendPaymentFailedEmail", "api.user.send_password_reset.send.app_error", nil, "err="+err.Error(), http.StatusInternalServerError)
 	}
 

app/email_batching.go

@@ -15,7 +15,6 @@ import (
 	"github.com/mattermost/mattermost-server/v5/model"
 	"github.com/mattermost/mattermost-server/v5/shared/i18n"
 	"github.com/mattermost/mattermost-server/v5/shared/mlog"
-	"github.com/mattermost/mattermost-server/v5/utils"
 )
 
 const (
@@ -222,7 +221,13 @@ func (es *EmailService) sendBatchedEmailNotification(userID string, notification
 			emailNotificationContentsType = *es.srv.Config().EmailSettings.EmailNotificationContentsType
 		}
 
-		contents += es.renderBatchedPost(notification, channel, sender, *es.srv.Config().ServiceSettings.SiteURL, displayNameFormat, translateFunc, user.Locale, emailNotificationContentsType)
+		postContent, err := es.renderBatchedPost(notification, channel, sender, *es.srv.Config().ServiceSettings.SiteURL, displayNameFormat, translateFunc, user.Locale, emailNotificationContentsType)
+		if err != nil {
+			mlog.Warn("Unable to render post for batched email notification template", mlog.Err(err))
+			continue
+		}
+
+		contents += postContent
 	}
 
 	tm := time.Unix(notifications[0].post.CreateAt/1000, 0)
@@ -234,34 +239,39 @@ func (es *EmailService) sendBatchedEmailNotification(userID string, notification
 		"Day":      tm.Day(),
 	})
 
-	body := es.newEmailTemplate("post_batched_body", user.Locale)
-	body.Props["SiteURL"] = *es.srv.Config().ServiceSettings.SiteURL
-	body.Props["Posts"] = template.HTML(contents)
-	body.Props["BodyText"] = translateFunc("api.email_batching.send_batched_email_notification.body_text", len(notifications))
+	data := es.newEmailTemplateData(user.Locale)
+	data.Props["SiteURL"] = *es.srv.Config().ServiceSettings.SiteURL
+	data.Props["Posts"] = template.HTML(contents)
+	data.Props["BodyText"] = translateFunc("api.email_batching.send_batched_email_notification.body_text", len(notifications))
 
-	if nErr := es.sendNotificationMail(user.Email, subject, body.Render()); nErr != nil {
+	body, err2 := es.srv.TemplatesContainer().RenderToString("post_batched_body", data)
+	if err2 != nil {
+		mlog.Warn("Unable build the batched email notification template", mlog.Err(err2))
+		return
+	}
+
+	if nErr := es.sendNotificationMail(user.Email, subject, body); nErr != nil {
 		mlog.Warn("Unable to send batched email notification", mlog.String("email", user.Email), mlog.Err(nErr))
 	}
 }
 
-func (es *EmailService) renderBatchedPost(notification *batchedNotification, channel *model.Channel, sender *model.User, siteURL string, displayNameFormat string, translateFunc i18n.TranslateFunc, userLocale string, emailNotificationContentsType string) string {
+func (es *EmailService) renderBatchedPost(notification *batchedNotification, channel *model.Channel, sender *model.User, siteURL string, displayNameFormat string, translateFunc i18n.TranslateFunc, userLocale string, emailNotificationContentsType string) (string, error) {
 	// don't include message contents if email notification contents type is set to generic
-	var template *utils.HTMLTemplate
+	var templateName = "post_batched_post_generic"
 	if emailNotificationContentsType == model.EMAIL_NOTIFICATION_CONTENTS_FULL {
-		template = es.newEmailTemplate("post_batched_post_full", userLocale)
-	} else {
-		template = es.newEmailTemplate("post_batched_post_generic", userLocale)
+		templateName = "post_batched_post_full"
 	}
 
-	template.Props["Button"] = translateFunc("api.email_batching.render_batched_post.go_to_post")
-	template.Props["PostMessage"] = es.srv.GetMessageForNotification(notification.post, translateFunc)
-	template.Props["PostLink"] = siteURL + "/" + notification.teamName + "/pl/" + notification.post.Id
-	template.Props["SenderName"] = sender.GetDisplayName(displayNameFormat)
+	data := es.newEmailTemplateData(userLocale)
+	data.Props["Button"] = translateFunc("api.email_batching.render_batched_post.go_to_post")
+	data.Props["PostMessage"] = es.srv.GetMessageForNotification(notification.post, translateFunc)
+	data.Props["PostLink"] = siteURL + "/" + notification.teamName + "/pl/" + notification.post.Id
+	data.Props["SenderName"] = sender.GetDisplayName(displayNameFormat)
 
 	tm := time.Unix(notification.post.CreateAt/1000, 0)
 	timezone, _ := tm.Zone()
 
-	template.Props["Date"] = translateFunc("api.email_batching.render_batched_post.date", map[string]interface{}{
+	data.Props["Date"] = translateFunc("api.email_batching.render_batched_post.date", map[string]interface{}{
 		"Year":     tm.Year(),
 		"Month":    translateFunc(tm.Month().String()),
 		"Day":      tm.Day(),
@@ -271,17 +281,17 @@ func (es *EmailService) renderBatchedPost(notification *batchedNotification, cha
 	})
 
 	if channel.Type == model.CHANNEL_DIRECT {
-		template.Props["ChannelName"] = translateFunc("api.email_batching.render_batched_post.direct_message")
+		data.Props["ChannelName"] = translateFunc("api.email_batching.render_batched_post.direct_message")
 	} else if channel.Type == model.CHANNEL_GROUP {
-		template.Props["ChannelName"] = translateFunc("api.email_batching.render_batched_post.group_message")
+		data.Props["ChannelName"] = translateFunc("api.email_batching.render_batched_post.group_message")
 	} else {
 		// don't include channel name if email notification contents type is set to generic
 		if emailNotificationContentsType == model.EMAIL_NOTIFICATION_CONTENTS_FULL {
-			template.Props["ChannelName"] = channel.DisplayName
+			data.Props["ChannelName"] = channel.DisplayName
 		} else {
-			template.Props["ChannelName"] = translateFunc("api.email_batching.render_batched_post.notification")
+			data.Props["ChannelName"] = translateFunc("api.email_batching.render_batched_post.notification")
 		}
 	}
 
-	return template.Render()
+	return es.srv.TemplatesContainer().RenderToString(templateName, data)
 }

app/email_batching_test.go

@@ -304,7 +304,8 @@ func TestRenderBatchedPostGeneric(t *testing.T) {
 		return translationID
 	}
 
-	var rendered = th.Server.EmailService.renderBatchedPost(notification, channel, sender, "http://localhost:8065", "", translateFunc, "en", model.EMAIL_NOTIFICATION_CONTENTS_GENERIC)
+	rendered, err := th.Server.EmailService.renderBatchedPost(notification, channel, sender, "http://localhost:8065", "", translateFunc, "en", model.EMAIL_NOTIFICATION_CONTENTS_GENERIC)
+	require.NoError(t, err)
 	require.NotContains(t, rendered, post.Message, "Rendered email should not contain post contents when email notification contents type is set to Generic.")
 }
 
@@ -329,6 +330,7 @@ func TestRenderBatchedPostFull(t *testing.T) {
 		return translationID
 	}
 
-	var rendered = th.Server.EmailService.renderBatchedPost(notification, channel, sender, "http://localhost:8065", "", translateFunc, "en", model.EMAIL_NOTIFICATION_CONTENTS_FULL)
+	rendered, err := th.Server.EmailService.renderBatchedPost(notification, channel, sender, "http://localhost:8065", "", translateFunc, "en", model.EMAIL_NOTIFICATION_CONTENTS_FULL)
+	require.NoError(t, err)
 	require.Contains(t, rendered, post.Message, "Rendered email should contain post contents when email notification contents type is set to Full.")
 }

app/notification.go

@@ -231,7 +231,10 @@ func (a *App) SendNotifications(post *model.Post, team *model.Team, channel *mod
 			}
 
 			if a.userAllowsEmail(profileMap[id], channelMemberNotifyPropsMap[id], post) {
-				a.sendNotificationEmail(notification, profileMap[id], team)
+				err := a.sendNotificationEmail(notification, profileMap[id], team)
+				if err != nil {
+					mlog.Warn("Unable to send notification email.", mlog.Err(err))
+				}
 			}
 		}
 	}

app/notification_email.go

@@ -7,7 +7,6 @@ import (
 	"fmt"
 	"html"
 	"html/template"
-	"net/http"
 	"net/url"
 	"path/filepath"
 	"strings"
@@ -16,17 +15,17 @@ import (
 	"github.com/mattermost/mattermost-server/v5/model"
 	"github.com/mattermost/mattermost-server/v5/shared/i18n"
 	"github.com/mattermost/mattermost-server/v5/shared/mlog"
-	"github.com/mattermost/mattermost-server/v5/utils"
+	"github.com/pkg/errors"
 )
 
-func (a *App) sendNotificationEmail(notification *PostNotification, user *model.User, team *model.Team) *model.AppError {
+func (a *App) sendNotificationEmail(notification *PostNotification, user *model.User, team *model.Team) error {
 	channel := notification.Channel
 	post := notification.Post
 
 	if channel.IsGroupOrDirect() {
 		teams, err := a.Srv().Store.Team().GetTeamsByUserId(user.Id)
 		if err != nil {
-			return model.NewAppError("sendNotificationEmail", "app.team.get_all.app_error", nil, err.Error(), http.StatusInternalServerError)
+			return errors.Wrap(err, "unable to get user teams")
 		}
 
 		// if the recipient isn't in the current user's team, just pick one
@@ -97,7 +96,10 @@ func (a *App) sendNotificationEmail(notification *PostNotification, user *model.
 	}
 
 	landingURL := a.GetSiteURL() + "/landing#/" + team.Name
-	var bodyText = a.getNotificationEmailBody(user, post, channel, channelName, senderName, team.Name, landingURL, emailNotificationContentsType, useMilitaryTime, translateFunc)
+	var bodyText, err = a.getNotificationEmailBody(user, post, channel, channelName, senderName, team.Name, landingURL, emailNotificationContentsType, useMilitaryTime, translateFunc)
+	if err != nil {
+		return errors.Wrap(err, "unable to render the email notification template")
+	}
 
 	a.Srv().Go(func() {
 		if nErr := a.Srv().EmailService.sendNotificationMail(user.Email, html.UnescapeString(subjectText), bodyText); nErr != nil {
@@ -163,11 +165,12 @@ func getGroupMessageNotificationEmailSubject(user *model.User, post *model.Post,
 /**
  * Computes the email body for notification messages
  */
-func (a *App) getNotificationEmailBody(recipient *model.User, post *model.Post, channel *model.Channel, channelName string, senderName string, teamName string, landingURL string, emailNotificationContentsType string, useMilitaryTime bool, translateFunc i18n.TranslateFunc) string {
+func (a *App) getNotificationEmailBody(recipient *model.User, post *model.Post, channel *model.Channel, channelName string, senderName string, teamName string, landingURL string, emailNotificationContentsType string, useMilitaryTime bool, translateFunc i18n.TranslateFunc) (string, error) {
 	// only include message contents in notification email if email notification contents type is set to full
-	var bodyPage *utils.HTMLTemplate
+	var templateName = "post_body_generic"
+	data := a.Srv().EmailService.newEmailTemplateData(recipient.Locale)
 	if emailNotificationContentsType == model.EMAIL_NOTIFICATION_CONTENTS_FULL {
-		bodyPage = a.Srv().EmailService.newEmailTemplate("post_body_full", recipient.Locale)
+		templateName = "post_body_full"
 		postMessage := a.GetMessageForNotification(post, translateFunc)
 		postMessage = html.EscapeString(postMessage)
 		normalizedPostMessage, err := a.generateHyperlinkForChannels(postMessage, teamName, landingURL)
@@ -175,16 +178,14 @@ func (a *App) getNotificationEmailBody(recipient *model.User, post *model.Post,
 			mlog.Warn("Encountered error while generating hyperlink for channels", mlog.String("team_name", teamName), mlog.Err(err))
 			normalizedPostMessage = postMessage
 		}
-		bodyPage.Props["PostMessage"] = template.HTML(normalizedPostMessage)
-	} else {
-		bodyPage = a.Srv().EmailService.newEmailTemplate("post_body_generic", recipient.Locale)
+		data.Props["PostMessage"] = template.HTML(normalizedPostMessage)
 	}
 
-	bodyPage.Props["SiteURL"] = a.GetSiteURL()
+	data.Props["SiteURL"] = a.GetSiteURL()
 	if teamName != "select_team" {
-		bodyPage.Props["TeamLink"] = landingURL + "/pl/" + post.Id
+		data.Props["TeamLink"] = landingURL + "/pl/" + post.Id
 	} else {
-		bodyPage.Props["TeamLink"] = landingURL
+		data.Props["TeamLink"] = landingURL
 	}
 
 	t := getFormattedPostTime(recipient, post, useMilitaryTime, translateFunc)
@@ -198,51 +199,51 @@ func (a *App) getNotificationEmailBody(recipient *model.User, post *model.Post,
 	}
 	if channel.Type == model.CHANNEL_DIRECT {
 		if emailNotificationContentsType == model.EMAIL_NOTIFICATION_CONTENTS_FULL {
-			bodyPage.Props["BodyText"] = translateFunc("app.notification.body.intro.direct.full")
-			bodyPage.Props["Info1"] = ""
+			data.Props["BodyText"] = translateFunc("app.notification.body.intro.direct.full")
+			data.Props["Info1"] = ""
 			info["SenderName"] = senderName
-			bodyPage.Props["Info2"] = translateFunc("app.notification.body.text.direct.full", info)
+			data.Props["Info2"] = translateFunc("app.notification.body.text.direct.full", info)
 		} else {
-			bodyPage.Props["BodyText"] = translateFunc("app.notification.body.intro.direct.generic", map[string]interface{}{
+			data.Props["BodyText"] = translateFunc("app.notification.body.intro.direct.generic", map[string]interface{}{
 				"SenderName": senderName,
 			})
-			bodyPage.Props["Info"] = translateFunc("app.notification.body.text.direct.generic", info)
+			data.Props["Info"] = translateFunc("app.notification.body.text.direct.generic", info)
 		}
 	} else if channel.Type == model.CHANNEL_GROUP {
 		if emailNotificationContentsType == model.EMAIL_NOTIFICATION_CONTENTS_FULL {
-			bodyPage.Props["BodyText"] = translateFunc("app.notification.body.intro.group_message.full")
-			bodyPage.Props["Info1"] = translateFunc("app.notification.body.text.group_message.full",
+			data.Props["BodyText"] = translateFunc("app.notification.body.intro.group_message.full")
+			data.Props["Info1"] = translateFunc("app.notification.body.text.group_message.full",
 				map[string]interface{}{
 					"ChannelName": channelName,
 				})
 			info["SenderName"] = senderName
-			bodyPage.Props["Info2"] = translateFunc("app.notification.body.text.group_message.full2", info)
+			data.Props["Info2"] = translateFunc("app.notification.body.text.group_message.full2", info)
 		} else {
-			bodyPage.Props["BodyText"] = translateFunc("app.notification.body.intro.group_message.generic", map[string]interface{}{
+			data.Props["BodyText"] = translateFunc("app.notification.body.intro.group_message.generic", map[string]interface{}{
 				"SenderName": senderName,
 			})
-			bodyPage.Props["Info"] = translateFunc("app.notification.body.text.group_message.generic", info)
+			data.Props["Info"] = translateFunc("app.notification.body.text.group_message.generic", info)
 		}
 	} else {
 		if emailNotificationContentsType == model.EMAIL_NOTIFICATION_CONTENTS_FULL {
-			bodyPage.Props["BodyText"] = translateFunc("app.notification.body.intro.notification.full")
-			bodyPage.Props["Info1"] = translateFunc("app.notification.body.text.notification.full",
+			data.Props["BodyText"] = translateFunc("app.notification.body.intro.notification.full")
+			data.Props["Info1"] = translateFunc("app.notification.body.text.notification.full",
 				map[string]interface{}{
 					"ChannelName": channelName,
 				})
 			info["SenderName"] = senderName
-			bodyPage.Props["Info2"] = translateFunc("app.notification.body.text.notification.full2", info)
+			data.Props["Info2"] = translateFunc("app.notification.body.text.notification.full2", info)
 		} else {
-			bodyPage.Props["BodyText"] = translateFunc("app.notification.body.intro.notification.generic", map[string]interface{}{
+			data.Props["BodyText"] = translateFunc("app.notification.body.intro.notification.generic", map[string]interface{}{
 				"SenderName": senderName,
 			})
-			bodyPage.Props["Info"] = translateFunc("app.notification.body.text.notification.generic", info)
+			data.Props["Info"] = translateFunc("app.notification.body.text.notification.generic", info)
 		}
 	}
 
-	bodyPage.Props["Button"] = translateFunc("api.templates.post_body.button")
+	data.Props["Button"] = translateFunc("api.templates.post_body.button")
 
-	return bodyPage.Render()
+	return a.Srv().TemplatesContainer().RenderToString(templateName, data)
 }
 
 type formattedPostTime struct {

app/notification_email_test.go

@@ -91,7 +91,8 @@ func TestGetNotificationEmailBodyFullNotificationPublicChannel(t *testing.T) {
 	teamStoreMock.On("GetByName", "testteam").Return(&model.Team{Name: "testteam"}, nil)
 	storeMock.On("Team").Return(&teamStoreMock)
 
-	body := th.App.getNotificationEmailBody(recipient, post, channel, channelName, senderName, teamName, teamURL, emailNotificationContentsType, true, translateFunc)
+	body, err := th.App.getNotificationEmailBody(recipient, post, channel, channelName, senderName, teamName, teamURL, emailNotificationContentsType, true, translateFunc)
+	require.NoError(t, err)
 	require.Contains(t, body, "You have a new notification.", fmt.Sprintf("Expected email text 'You have a new notification. Got %s", body))
 	require.Contains(t, body, "Channel: "+channel.DisplayName, "Expected email text 'Channel: %s'. Got %s", channel.DisplayName, body)
 	require.Contains(t, body, senderName+" - ", fmt.Sprintf("Expected email text '%s - '. Got %s", senderName, body))
@@ -123,7 +124,8 @@ func TestGetNotificationEmailBodyFullNotificationGroupChannel(t *testing.T) {
 	teamStoreMock.On("GetByName", "testteam").Return(&model.Team{Name: "testteam"}, nil)
 	storeMock.On("Team").Return(&teamStoreMock)
 
-	body := th.App.getNotificationEmailBody(recipient, post, channel, channelName, senderName, teamName, teamURL, emailNotificationContentsType, true, translateFunc)
+	body, err := th.App.getNotificationEmailBody(recipient, post, channel, channelName, senderName, teamName, teamURL, emailNotificationContentsType, true, translateFunc)
+	require.NoError(t, err)
 	require.Contains(t, body, "You have a new Group Message.", fmt.Sprintf("Expected email text 'You have a new Group Message. Got "+body))
 	require.Contains(t, body, "Channel: ChannelName", fmt.Sprintf("Expected email text 'Channel: ChannelName'. Got %s", body))
 	require.Contains(t, body, senderName+" - ", fmt.Sprintf("Expected email text '%s - '. Got %s", senderName, body))
@@ -155,7 +157,8 @@ func TestGetNotificationEmailBodyFullNotificationPrivateChannel(t *testing.T) {
 	teamStoreMock.On("GetByName", "testteam").Return(&model.Team{Name: "testteam"}, nil)
 	storeMock.On("Team").Return(&teamStoreMock)
 
-	body := th.App.getNotificationEmailBody(recipient, post, channel, channelName, senderName, teamName, teamURL, emailNotificationContentsType, true, translateFunc)
+	body, err := th.App.getNotificationEmailBody(recipient, post, channel, channelName, senderName, teamName, teamURL, emailNotificationContentsType, true, translateFunc)
+	require.NoError(t, err)
 	require.Contains(t, body, "You have a new notification.", fmt.Sprintf("Expected email text 'You have a new notification. Got "+body))
 	require.Contains(t, body, "Channel: "+channel.DisplayName, fmt.Sprintf("Expected email text 'Channel: "+channel.DisplayName+"'. Got "+body))
 	require.Contains(t, body, senderName+" - ", fmt.Sprintf("Expected email text '%s - '. Got %s", senderName, body))
@@ -187,7 +190,8 @@ func TestGetNotificationEmailBodyFullNotificationDirectChannel(t *testing.T) {
 	teamStoreMock.On("GetByName", "testteam").Return(&model.Team{Name: "testteam"}, nil)
 	storeMock.On("Team").Return(&teamStoreMock)
 
-	body := th.App.getNotificationEmailBody(recipient, post, channel, channelName, senderName, teamName, teamURL, emailNotificationContentsType, true, translateFunc)
+	body, err := th.App.getNotificationEmailBody(recipient, post, channel, channelName, senderName, teamName, teamURL, emailNotificationContentsType, true, translateFunc)
+	require.NoError(t, err)
 	require.Contains(t, body, "You have a new Direct Message.", fmt.Sprintf("Expected email text 'You have a new Direct Message. Got "+body))
 	require.Contains(t, body, senderName+" - ", fmt.Sprintf("Expected email text '%s - '. Got %s", senderName, body))
 	require.Contains(t, body, post.Message, fmt.Sprintf("Expected email text '%s'. Got %s", post.Message, body))
@@ -222,7 +226,8 @@ func TestGetNotificationEmailBodyFullNotificationLocaleTimeWithTimezone(t *testi
 	teamStoreMock.On("GetByName", "testteam").Return(&model.Team{Name: "testteam"}, nil)
 	storeMock.On("Team").Return(&teamStoreMock)
 
-	body := th.App.getNotificationEmailBody(recipient, post, channel, channelName, senderName, teamName, teamURL, emailNotificationContentsType, false, translateFunc)
+	body, err := th.App.getNotificationEmailBody(recipient, post, channel, channelName, senderName, teamName, teamURL, emailNotificationContentsType, false, translateFunc)
+	require.NoError(t, err)
 	r, _ := regexp.Compile("E([S|D]+)T")
 	zone := r.FindString(body)
 	require.Contains(t, body, "sender - 9:43 AM "+zone+", April 25", fmt.Sprintf("Expected email text 'sender - 9:43 AM %s, April 25'. Got %s", zone, body))
@@ -274,7 +279,8 @@ func TestGetNotificationEmailBodyFullNotificationLocaleTimeNoTimezone(t *testing
 	err = tmp.Execute(&text, fmt.Sprintf("sender - %s:%s %s, %s %s", formattedTime.Hour, formattedTime.Minute, formattedTime.TimeZone, formattedTime.Month, formattedTime.Day))
 	require.NoError(t, err)
 
-	body := th.App.getNotificationEmailBody(recipient, post, channel, channelName, senderName, teamName, teamURL, emailNotificationContentsType, true, translateFunc)
+	body, err := th.App.getNotificationEmailBody(recipient, post, channel, channelName, senderName, teamName, teamURL, emailNotificationContentsType, true, translateFunc)
+	require.NoError(t, err)
 	postTimeLine := text.String()
 	require.Contains(t, body, postTimeLine, fmt.Sprintf("Expected email text '%s'. Got %s", postTimeLine, body))
 }
@@ -307,7 +313,8 @@ func TestGetNotificationEmailBodyFullNotificationLocaleTime12Hour(t *testing.T)
 	teamStoreMock.On("GetByName", "testteam").Return(&model.Team{Name: "testteam"}, nil)
 	storeMock.On("Team").Return(&teamStoreMock)
 
-	body := th.App.getNotificationEmailBody(recipient, post, channel, channelName, senderName, teamName, teamURL, emailNotificationContentsType, false, translateFunc)
+	body, err := th.App.getNotificationEmailBody(recipient, post, channel, channelName, senderName, teamName, teamURL, emailNotificationContentsType, false, translateFunc)
+	require.NoError(t, err)
 	require.Contains(t, body, "sender - 2:30 PM", fmt.Sprintf("Expected email text 'sender - 2:30 PM'. Got %s", body))
 	require.Contains(t, body, "April 25", fmt.Sprintf("Expected email text 'April 25'. Got %s", body))
 }
@@ -340,7 +347,8 @@ func TestGetNotificationEmailBodyFullNotificationLocaleTime24Hour(t *testing.T)
 	teamStoreMock.On("GetByName", "testteam").Return(&model.Team{Name: "testteam"}, nil)
 	storeMock.On("Team").Return(&teamStoreMock)
 
-	body := th.App.getNotificationEmailBody(recipient, post, channel, channelName, senderName, teamName, teamURL, emailNotificationContentsType, true, translateFunc)
+	body, err := th.App.getNotificationEmailBody(recipient, post, channel, channelName, senderName, teamName, teamURL, emailNotificationContentsType, true, translateFunc)
+	require.NoError(t, err)
 	require.Contains(t, body, "sender - 14:30", fmt.Sprintf("Expected email text 'sender - 14:30'. Got %s", body))
 	require.Contains(t, body, "April 25", fmt.Sprintf("Expected email text 'April 25'. Got %s", body))
 }
@@ -370,7 +378,8 @@ func TestGetNotificationEmailBodyGenericNotificationPublicChannel(t *testing.T)
 	teamStoreMock.On("GetByName", "testteam").Return(&model.Team{Name: "testteam"}, nil)
 	storeMock.On("Team").Return(&teamStoreMock)
 
-	body := th.App.getNotificationEmailBody(recipient, post, channel, channelName, senderName, teamName, teamURL, emailNotificationContentsType, true, translateFunc)
+	body, err := th.App.getNotificationEmailBody(recipient, post, channel, channelName, senderName, teamName, teamURL, emailNotificationContentsType, true, translateFunc)
+	require.NoError(t, err)
 	require.Contains(t, body, "You have a new notification from "+senderName, fmt.Sprintf("Expected email text 'You have a new notification from %s'. Got %s", senderName, body))
 	require.False(t, strings.Contains(body, "Channel: "+channel.DisplayName), fmt.Sprintf("Did not expect email text 'CHANNEL: %s'. Got %s", channel.DisplayName, body))
 	require.False(t, strings.Contains(body, post.Message), fmt.Sprintf("Did not expect email text '%s'. Got %s", post.Message, body))
@@ -401,7 +410,8 @@ func TestGetNotificationEmailBodyGenericNotificationGroupChannel(t *testing.T) {
 	teamStoreMock.On("GetByName", "testteam").Return(&model.Team{Name: "testteam"}, nil)
 	storeMock.On("Team").Return(&teamStoreMock)
 
-	body := th.App.getNotificationEmailBody(recipient, post, channel, channelName, senderName, teamName, teamURL, emailNotificationContentsType, true, translateFunc)
+	body, err := th.App.getNotificationEmailBody(recipient, post, channel, channelName, senderName, teamName, teamURL, emailNotificationContentsType, true, translateFunc)
+	require.NoError(t, err)
 	require.Contains(t, body, "You have a new Group Message from "+senderName, fmt.Sprintf("Expected email text 'You have a new Group Message from %s'. Got %s", senderName, body))
 	require.False(t, strings.Contains(body, "CHANNEL: "+channel.DisplayName), fmt.Sprintf("Did not expect email text 'CHANNEL: %s'. Got %s", channel.DisplayName, body))
 	require.False(t, strings.Contains(body, post.Message), fmt.Sprintf("Did not expect email text '%s'. Got %s", post.Message, body))
@@ -432,7 +442,8 @@ func TestGetNotificationEmailBodyGenericNotificationPrivateChannel(t *testing.T)
 	teamStoreMock.On("GetByName", "testteam").Return(&model.Team{Name: "testteam"}, nil)
 	storeMock.On("Team").Return(&teamStoreMock)
 
-	body := th.App.getNotificationEmailBody(recipient, post, channel, channelName, senderName, teamName, teamURL, emailNotificationContentsType, true, translateFunc)
+	body, err := th.App.getNotificationEmailBody(recipient, post, channel, channelName, senderName, teamName, teamURL, emailNotificationContentsType, true, translateFunc)
+	require.NoError(t, err)
 	require.Contains(t, body, "You have a new notification from "+senderName, fmt.Sprintf("Expected email text 'You have a new notification from %s'. Got %s", senderName, body))
 	require.False(t, strings.Contains(body, "CHANNEL: "+channel.DisplayName), fmt.Sprintf("Did not expect email text 'CHANNEL: %s'. Got %s", channel.DisplayName, body))
 	require.False(t, strings.Contains(body, post.Message), fmt.Sprintf("Did not expect email text '%s'. Got %s", post.Message, body))
@@ -463,7 +474,8 @@ func TestGetNotificationEmailBodyGenericNotificationDirectChannel(t *testing.T)
 	teamStoreMock.On("GetByName", "testteam").Return(&model.Team{Name: "testteam"}, nil)
 	storeMock.On("Team").Return(&teamStoreMock)
 
-	body := th.App.getNotificationEmailBody(recipient, post, channel, channelName, senderName, teamName, teamURL, emailNotificationContentsType, true, translateFunc)
+	body, err := th.App.getNotificationEmailBody(recipient, post, channel, channelName, senderName, teamName, teamURL, emailNotificationContentsType, true, translateFunc)
+	require.NoError(t, err)
 	require.Contains(t, body, "You have a new Direct Message from "+senderName, fmt.Sprintf("Expected email text 'You have a new Direct Message from "+senderName+"'. Got "+body))
 	require.False(t, strings.Contains(body, "CHANNEL: "+channel.DisplayName), fmt.Sprintf("Did not expect email text 'CHANNEL: %s'. Got %s", channel.DisplayName, body))
 	require.False(t, strings.Contains(body, post.Message), fmt.Sprintf("Did not expect email text '%s'. Got %s", post.Message, body))
@@ -496,9 +508,10 @@ func TestGetNotificationEmailEscapingChars(t *testing.T) {
 	teamStoreMock.On("GetByName", "testteam").Return(&model.Team{Name: "testteam"}, nil)
 	storeMock.On("Team").Return(&teamStoreMock)
 
-	body := th.App.getNotificationEmailBody(recipient, post, ch,
+	body, err := th.App.getNotificationEmailBody(recipient, post, ch,
 		channelName, senderName, teamName, teamURL,
 		emailNotificationContentsType, true, translateFunc)
+	require.NoError(t, err)
 
 	assert.NotContains(t, body, message)
 }
@@ -539,9 +552,10 @@ func TestGetNotificationEmailBodyPublicChannelMention(t *testing.T) {
 	channelStoreMock.On("GetByNames", "test", []string{ch.Name}, true).Return([]*model.Channel{ch}, nil)
 	storeMock.On("Channel").Return(&channelStoreMock)
 
-	body := th.App.getNotificationEmailBody(recipient, post, ch,
+	body, err := th.App.getNotificationEmailBody(recipient, post, ch,
 		ch.Name, senderName, teamName, teamURL,
 		emailNotificationContentsType, true, translateFunc)
+	require.NoError(t, err)
 	channelURL := teamURL + "/channels/" + ch.Name
 	mention := "~" + ch.Name
 	assert.Contains(t, body, "<a href='"+channelURL+"'>"+mention+"</a>")
@@ -604,9 +618,10 @@ func TestGetNotificationEmailBodyMultiPublicChannelMention(t *testing.T) {
 	channelStoreMock.On("GetByNames", "test", []string{ch.Name, ch2.Name, ch3.Name}, true).Return([]*model.Channel{ch, ch2, ch3}, nil)
 	storeMock.On("Channel").Return(&channelStoreMock)
 
-	body := th.App.getNotificationEmailBody(recipient, post, ch,
+	body, err := th.App.getNotificationEmailBody(recipient, post, ch,
 		ch.Name, senderName, teamName, teamURL,
 		emailNotificationContentsType, true, translateFunc)
+	require.NoError(t, err)
 	channelURL := teamURL + "/channels/" + ch.Name
 	channelURL2 := teamURL + "/channels/" + ch2.Name
 	channelURL3 := teamURL + "/channels/" + ch3.Name
@@ -652,9 +667,10 @@ func TestGetNotificationEmailBodyPrivateChannelMention(t *testing.T) {
 	channelStoreMock.On("GetByNames", "test", []string{ch.Name}, true).Return([]*model.Channel{ch}, nil)
 	storeMock.On("Channel").Return(&channelStoreMock)
 
-	body := th.App.getNotificationEmailBody(recipient, post, ch,
+	body, err := th.App.getNotificationEmailBody(recipient, post, ch,
 		ch.Name, senderName, teamName, teamURL,
 		emailNotificationContentsType, true, translateFunc)
+	require.NoError(t, err)
 	channelURL := teamURL + "/channels/" + ch.Name
 	mention := "~" + ch.Name
 	assert.NotContains(t, body, "<a href='"+channelURL+"'>"+mention+"</a>")
@@ -797,7 +813,8 @@ func TestLandingLink(t *testing.T) {
 	teamStoreMock.On("GetByName", "testteam").Return(&model.Team{Name: "testteam"}, nil)
 	storeMock.On("Team").Return(&teamStoreMock)
 
-	body := th.App.getNotificationEmailBody(recipient, post, channel, channelName, senderName, teamName, teamURL, emailNotificationContentsType, true, translateFunc)
+	body, err := th.App.getNotificationEmailBody(recipient, post, channel, channelName, senderName, teamName, teamURL, emailNotificationContentsType, true, translateFunc)
+	require.NoError(t, err)
 	require.Contains(t, body, teamURL, fmt.Sprintf("Expected email text '%s'. Got %s", teamURL, body))
 }
 
@@ -826,6 +843,7 @@ func TestLandingLinkPermalink(t *testing.T) {
 	teamStoreMock.On("GetByName", "testteam").Return(&model.Team{Name: "testteam"}, nil)
 	storeMock.On("Team").Return(&teamStoreMock)
 
-	body := th.App.getNotificationEmailBody(recipient, post, channel, channelName, senderName, teamName, teamURL, emailNotificationContentsType, true, translateFunc)
+	body, err := th.App.getNotificationEmailBody(recipient, post, channel, channelName, senderName, teamName, teamURL, emailNotificationContentsType, true, translateFunc)
+	require.NoError(t, err)
 	require.Contains(t, body, teamURL+"/pl/"+post.Id, fmt.Sprintf("Expected email text '%s'. Got %s", teamURL, body))
 }

app/server.go

@@ -58,6 +58,7 @@ import (
 	"github.com/mattermost/mattermost-server/v5/shared/filestore"
 	"github.com/mattermost/mattermost-server/v5/shared/i18n"
 	"github.com/mattermost/mattermost-server/v5/shared/mlog"
+	"github.com/mattermost/mattermost-server/v5/shared/templates"
 	"github.com/mattermost/mattermost-server/v5/store"
 	"github.com/mattermost/mattermost-server/v5/store/localcachelayer"
 	"github.com/mattermost/mattermost-server/v5/store/retrylayer"
@@ -65,6 +66,7 @@ import (
 	"github.com/mattermost/mattermost-server/v5/store/sqlstore"
 	"github.com/mattermost/mattermost-server/v5/store/timerlayer"
 	"github.com/mattermost/mattermost-server/v5/utils"
+	"github.com/mattermost/mattermost-server/v5/utils/fileutils"
 )
 
 var MaxNotificationsPerChannelDefault int64 = 1000000
@@ -133,7 +135,7 @@ type Server struct {
 
 	newStore func() (store.Store, error)
 
-	htmlTemplateWatcher     *utils.HTMLTemplateWatcher
+	htmlTemplateWatcher     *templates.Container
 	sessionCache            cache.Cache
 	seenPendingPostIdsCache cache.Cache
 	statusCache             cache.Cache
@@ -391,9 +393,19 @@ func NewServer(options ...Option) (*Server, error) {
 		}
 	}
 
-	if htmlTemplateWatcher, err2 := utils.NewHTMLTemplateWatcher("templates"); err2 != nil {
-		mlog.Error("Failed to parse server templates", mlog.Err(err2))
+	templatesDir, ok := fileutils.FindDir("templates")
+	if !ok {
+		mlog.Error("Failed find server templates", mlog.String("directory", "templates"))
 	} else {
+		htmlTemplateWatcher, errorsChan, err2 := templates.NewWithWatcher(templatesDir)
+		if err2 != nil {
+			return nil, errors.Wrap(err2, "cannot initialize server templates")
+		}
+		s.Go(func() {
+			for err2 := range errorsChan {
+				mlog.Warn("Server templates error", mlog.Err(err2))
+			}
+		})
 		s.htmlTemplateWatcher = htmlTemplateWatcher
 	}
 
@@ -865,13 +877,10 @@ func (s *Server) Shutdown() {
 	// Push notification hub needs to be shutdown after HTTP server
 	// to prevent stray requests from generating a push notification after it's shut down.
 	s.StopPushNotificationsHubWorkers()
+	s.htmlTemplateWatcher.Close()
 
 	s.WaitForGoroutines()
 
-	if s.htmlTemplateWatcher != nil {
-		s.htmlTemplateWatcher.Close()
-	}
-
 	if s.advancedLogListenerCleanup != nil {
 		s.advancedLogListenerCleanup()
 		s.advancedLogListenerCleanup = nil