Reduce the coupling of the mailservice with the rest of the application (#16898)

* Reduce the coupling of the mailservice with the rest of the application

* Fixing tests in CI

* Simplifiying mailservice config

* Addressing PR review comments

* Fixing tests

* Removing unnecesary type definition

* Fixing ServerName usage

app/admin.go

@@ -226,7 +226,8 @@ func (a *App) TestEmail(userID string, cfg *model.Config) *model.AppError {
 
 	T := utils.GetUserTranslations(user.Locale)
 	license := a.Srv().License()
-	if err := mailservice.SendMailUsingConfig(user.Email, T("api.admin.test_email.subject"), T("api.admin.test_email.body"), cfg, license != nil && *license.Features.Compliance, ""); err != nil {
+	mailConfig := a.Srv().MailServiceConfig()
+	if err := mailservice.SendMailUsingConfig(user.Email, T("api.admin.test_email.subject"), T("api.admin.test_email.body"), mailConfig, license != nil && *license.Features.Compliance, ""); err != nil {
 		return model.NewAppError("testEmail", "app.admin.test_email.failure", map[string]interface{}{"Error": err.Error()}, "", http.StatusInternalServerError)
 	}
 

app/app.go

@@ -497,7 +497,8 @@ func (a *App) NotifyAndSetWarnMetricAck(warnMetricId string, sender *model.User,
 			subject := T("api.templates.warn_metric_ack.subject")
 			bodyPage.Props["Title"] = warnMetricDisplayTexts.EmailBody
 
-			if err := mailservice.SendMailUsingConfig(model.MM_SUPPORT_ADVISOR_ADDRESS, subject, bodyPage.Render(), a.Config(), false, sender.Email); err != nil {
+			mailConfig := a.Srv().MailServiceConfig()
+			if err := mailservice.SendMailUsingConfig(model.MM_SUPPORT_ADVISOR_ADDRESS, subject, bodyPage.Render(), 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/config.go

@@ -22,6 +22,7 @@ import (
 	"github.com/mattermost/mattermost-server/v5/config"
 	"github.com/mattermost/mattermost-server/v5/mlog"
 	"github.com/mattermost/mattermost-server/v5/model"
+	"github.com/mattermost/mattermost-server/v5/services/mailservice"
 	"github.com/mattermost/mattermost-server/v5/utils"
 )
 
@@ -450,3 +451,25 @@ func (a *App) HandleMessageExportConfig(cfg *model.Config, appCfg *model.Config)
 		}
 	}
 }
+
+func (s *Server) MailServiceConfig() *mailservice.SMTPConfig {
+	emailSettings := s.Config().EmailSettings
+	hostname := utils.GetHostnameFromSiteURL(*s.Config().ServiceSettings.SiteURL)
+	cfg := mailservice.SMTPConfig{
+		Hostname:                          hostname,
+		ConnectionSecurity:                *emailSettings.ConnectionSecurity,
+		SkipServerCertificateVerification: *emailSettings.SkipServerCertificateVerification,
+		ServerName:                        *emailSettings.SMTPServer,
+		Server:                            *emailSettings.SMTPServer,
+		Port:                              *emailSettings.SMTPPort,
+		ServerTimeout:                     *emailSettings.SMTPServerTimeout,
+		Username:                          *emailSettings.SMTPUsername,
+		Password:                          *emailSettings.SMTPPassword,
+		EnableSMTPAuth:                    *emailSettings.EnableSMTPAuth,
+		SendEmailNotifications:            *emailSettings.SendEmailNotifications,
+		FeedbackName:                      *emailSettings.FeedbackName,
+		FeedbackEmail:                     *emailSettings.FeedbackEmail,
+		ReplyToAddress:                    *emailSettings.ReplyToAddress,
+	}
+	return &cfg
+}

app/email.go

@@ -558,14 +558,16 @@ func (es *EmailService) sendMail(to, subject, htmlBody string) error {
 
 func (es *EmailService) sendMailWithCC(to, subject, htmlBody string, ccMail string) error {
 	license := es.srv.License()
-	return mailservice.SendMailUsingConfig(to, subject, htmlBody, es.srv.Config(), license != nil && *license.Features.Compliance, ccMail)
+	mailConfig := es.srv.MailServiceConfig()
+
+	return mailservice.SendMailUsingConfig(to, subject, htmlBody, mailConfig, license != nil && *license.Features.Compliance, ccMail)
 }
 
 func (es *EmailService) sendMailWithEmbeddedFiles(to, subject, htmlBody string, embeddedFiles map[string]io.Reader) error {
 	license := es.srv.License()
-	config := es.srv.Config()
+	mailConfig := es.srv.MailServiceConfig()
 
-	return mailservice.SendMailWithEmbeddedFilesUsingConfig(to, subject, htmlBody, embeddedFiles, config, license != nil && *license.Features.Compliance, "")
+	return mailservice.SendMailWithEmbeddedFilesUsingConfig(to, subject, htmlBody, embeddedFiles, mailConfig, license != nil && *license.Features.Compliance, "")
 }
 
 func (es *EmailService) CreateVerifyEmailToken(userID string, newEmail string) (*model.Token, *model.AppError) {

app/security_update_check.go

@@ -115,7 +115,9 @@ func (s *Server) DoSecurityUpdateCheck() {
 					for _, user := range users {
 						mlog.Info("Sending security bulletin", mlog.String("bulletin_id", bulletin.Id), mlog.String("user_email", user.Email))
 						license := s.License()
-						mailservice.SendMailUsingConfig(user.Email, utils.T("mattermost.bulletin.subject"), string(body), s.Config(), license != nil && *license.Features.Compliance, "")
+						mailConfig := s.MailServiceConfig()
+
+						mailservice.SendMailUsingConfig(user.Email, utils.T("mattermost.bulletin.subject"), string(body), mailConfig, license != nil && *license.Features.Compliance, "")
 					}
 
 					bulletinSeen := &model.System{Name: "SecurityBulletin_" + bulletin.Id, Value: bulletin.Id}

app/server.go

@@ -487,7 +487,9 @@ func NewServer(options ...Option) (*Server, error) {
 	}
 	s.WebSocketRouter.app = fakeApp
 
-	if nErr := mailservice.TestConnection(s.Config()); nErr != nil {
+	mailConfig := s.MailServiceConfig()
+
+	if nErr := mailservice.TestConnection(mailConfig); nErr != nil {
 		mlog.Error("Mail server connection test is failed", mlog.Err(nErr))
 	}