notifications: Deprecate redundant encryptions settings

'tls' and 'ssl' are duplicates of 'starttls' and 'ssltls' and have been deprecated
in the upstream modules we use for sending mail notifications. Let's deprecate them
as well and issue a warning when they are still used.

Fixes: #7345

services/notifications/pkg/config/parser/parse.go

@@ -2,10 +2,12 @@ package parser
 
 import (
 	"errors"
+	"fmt"
 
 	ociscfg "github.com/owncloud/ocis/v2/ocis-pkg/config"
 	"github.com/owncloud/ocis/v2/services/notifications/pkg/config"
 	"github.com/owncloud/ocis/v2/services/notifications/pkg/config/defaults"
+	"github.com/owncloud/ocis/v2/services/notifications/pkg/logging"
 
 	"github.com/owncloud/ocis/v2/ocis-pkg/config/envdecode"
 )
@@ -33,5 +35,22 @@ func ParseConfig(cfg *config.Config) error {
 }
 
 func Validate(cfg *config.Config) error {
+	logger := logging.Configure(cfg.Service.Name, cfg.Log)
+
+	if cfg.Notifications.SMTP.Host != "" {
+		switch cfg.Notifications.SMTP.Encryption {
+		case "tls":
+			logger.Warn().Msg("The smtp_encryption value 'tls' is deprecated. Please use the value 'starttls' instead.")
+		case "ssl":
+			logger.Warn().Msg("The smtp_encryption value 'ssl' is deprecated. Please use the value 'ssltls' instead.")
+		case "starttls", "ssltls", "none":
+			break
+		default:
+			return fmt.Errorf(
+				"unknown value '%s' for 'smtp_encryption' in service %s. Allowed values are 'starttls', 'ssltls' or 'none'",
+				cfg.Notifications.SMTP.Encryption, cfg.Service.Name,
+			)
+		}
+	}
 	return nil
 }