make email templates configurable

Signed-off-by: Christian Richter <crichter@owncloud.com>

services/notifications/pkg/command/server.go

@@ -53,7 +53,7 @@ func Server(cfg *config.Config) *cli.Command {
 				logger.Fatal().Err(err).Str("addr", cfg.Notifications.RevaGateway).Msg("could not get reva client")
 			}
 
-			svc := service.NewEventsNotifier(evts, channel, logger, gwclient, cfg.Commons.MachineAuthAPIKey)
+			svc := service.NewEventsNotifier(evts, channel, logger, gwclient, cfg.Commons.MachineAuthAPIKey, cfg.Notifications.EmailTemplatePath)
 			return svc.Run()
 		},
 	}

services/notifications/pkg/config/config.go

@@ -26,6 +26,7 @@ type Notifications struct {
 	Events            Events `yaml:"events"`
 	RevaGateway       string `yaml:"reva_gateway" env:"REVA_GATEWAY;NOTIFICATIONS_REVA_GATEWAY" desc:"CS3 gateway used to look up user metadata"`
 	MachineAuthAPIKey string `yaml:"machine_auth_api_key" env:"OCIS_MACHINE_AUTH_API_KEY;NOTIFICATIONS_MACHINE_AUTH_API_KEY" desc:"Machine auth API key used to validate internal requests necessary to access resources from other services."`
+	EmailTemplatePath string `yaml:"email_template_path" env:"OCIS_EMAIL_TEMPLATE_PATH;NOTIFICATIONS_EMAIL_TEMPLATE_PATH" desc:"Path to the E-Mail templates for the notifications to override the embedded ones."`
 }
 
 // SMTP combines the smtp configuration options.

services/notifications/pkg/email/email.go

@@ -4,16 +4,30 @@ import (
 	"bytes"
 	"embed"
 	"html/template"
+	"path/filepath"
 )
 
 // go:embed templates/*.tmpl
 
 // RenderEmailTemplate renders the email template for a new share
-func RenderEmailTemplate(templateName string, templateVariables map[string]string) (string, error) {
+func RenderEmailTemplate(templateName string, templateVariables map[string]string, emailTemplatePath string) (string, error) {
 	var fs embed.FS
-	tpl, err := template.ParseFS(fs, templateName)
-	if err != nil {
-		return "", err
+	var err error
+	var tpl *template.Template
+	templateHasBeenFound := false
+	if emailTemplatePath != "" {
+		// try to lookup the files in the filesystem
+		tpl, err = template.ParseFiles(filepath.Join(emailTemplatePath, templateName))
+		if err == nil {
+			templateHasBeenFound = true
+		}
+	}
+	if !templateHasBeenFound {
+		// template has not been found in the fs, or path has not been specified => use embed templates
+		tpl, err = template.ParseFS(fs, templateName)
+		if err != nil {
+			return "", err
+		}
 	}
 	writer := bytes.NewBufferString("")
 	err = tpl.Execute(writer, templateVariables)

services/notifications/pkg/service/service.go

@@ -24,7 +24,8 @@ type Service interface {
 	Run() error
 }
 
-func NewEventsNotifier(events <-chan interface{}, channel channels.Channel, logger log.Logger, gwClient gateway.GatewayAPIClient, machineAuthAPIKey string) Service {
+// NewEventsNotifier provides a new eventsNotifier
+func NewEventsNotifier(events <-chan interface{}, channel channels.Channel, logger log.Logger, gwClient gateway.GatewayAPIClient, machineAuthAPIKey, emailTemplatePath string) Service {
 	return eventsNotifier{
 		logger:            logger,
 		channel:           channel,
@@ -32,6 +33,7 @@ func NewEventsNotifier(events <-chan interface{}, channel channels.Channel, logg
 		signals:           make(chan os.Signal, 1),
 		gwClient:          gwClient,
 		machineAuthAPIKey: machineAuthAPIKey,
+		emailTemplatePath: emailTemplatePath,
 	}
 }
 
@@ -42,6 +44,7 @@ type eventsNotifier struct {
 	signals           chan os.Signal
 	gwClient          gateway.GatewayAPIClient
 	machineAuthAPIKey string
+	emailTemplatePath string
 }
 
 func (s eventsNotifier) Run() error {
@@ -146,7 +149,7 @@ func (s eventsNotifier) handleShareCreated(e events.ShareCreated) {
 	msg, err := email.RenderEmailTemplate("shareCreated.email.tmpl", map[string]string{
 		"ShareSharer": userResponse.User.DisplayName,
 		"ShareFolder": md.Info.Name,
-	})
+	}, s.emailTemplatePath)
 
 	if err != nil {
 		s.logger.Error().