[MM-31112] - Update license renewal email (#16747)

* [MM-31112] - Update license renewal email

* Feedback impl-1

* Update app/license.go

Co-authored-by: Maria A Nunez <maria.nunez@mattermost.com>

* Feedback impl-2

Co-authored-by: Maria A Nunez <maria.nunez@mattermost.com>

app/email.go

@@ -520,7 +520,14 @@ func (es *EmailService) SendDeactivateAccountEmail(email string, locale, siteURL
 	return nil
 }
 
-func (es *EmailService) SendRemoveExpiredLicenseEmail(email string, locale, siteURL string, licenseId string) *model.AppError {
+// SendRemoveExpiredLicenseEmail formats an email and uses the email service to send the email to user with link pointing to CWS
+// to renew the user license
+func (es *EmailService) SendRemoveExpiredLicenseEmail(email string, locale, siteURL string) *model.AppError {
+	renewalLink, err := es.srv.GenerateLicenseRenewalLink()
+	if err != nil {
+		return err
+	}
+
 	T := utils.GetUserTranslations(locale)
 	subject := T("api.templates.remove_expired_license.subject",
 		map[string]interface{}{"SiteName": es.srv.Config().TeamSettings.SiteName})
@@ -528,7 +535,7 @@ func (es *EmailService) SendRemoveExpiredLicenseEmail(email string, locale, site
 	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"] = fmt.Sprintf("%s?id=%s", model.LICENSE_RENEWAL_LINK, licenseId)
+	bodyPage.Props["Link"] = renewalLink
 	bodyPage.Props["LinkButton"] = T("api.templates.remove_expired_license.body.renew_button")
 
 	if err := es.sendMail(email, subject, bodyPage.Render()); err != nil {

app/license.go

@@ -331,3 +331,13 @@ func (s *Server) renewalTokenValid(tokenString, signingKey string) (bool, error)
 	}
 	return true, nil
 }
+
+// GenerateLicenseRenewalLink returns a link that points to the CWS where clients can renew license
+func (s *Server) GenerateLicenseRenewalLink() (string, *model.AppError) {
+	renewalToken, err := s.GenerateRenewalToken(JWTDefaultTokenExpiration)
+	if err != nil {
+		return "", err
+	}
+	renewalLink := LicenseRenewalURL + "?token=" + renewalToken
+	return renewalLink, nil
+}

app/server.go

@@ -1456,7 +1456,7 @@ func doLicenseExpirationCheck(a *App) {
 
 		mlog.Debug("Sending license expired email.", mlog.String("user_email", user.Email))
 		a.Srv().Go(func() {
-			if err := a.Srv().EmailService.SendRemoveExpiredLicenseEmail(user.Email, user.Locale, *a.Config().ServiceSettings.SiteURL, license.Id); err != nil {
+			if err := a.Srv().EmailService.SendRemoveExpiredLicenseEmail(user.Email, user.Locale, *a.Config().ServiceSettings.SiteURL); err != nil {
 				mlog.Error("Error while sending the license expired email.", mlog.String("user_email", user.Email), mlog.Err(err))
 			}
 		})