feat: Hide secrets on api and channels

server/internal/services/channels.go

@@ -90,12 +90,57 @@ func CreateChannel(instanceID string, ch *models.NotificationChannel) (*models.N
 }
 
 func UpdateChannel(instanceID, channelID string, upd bson.M) error {
+	if cfg, ok := upd["config"].(map[string]string); ok {
+		merged, err := mergeChannelSecrets(instanceID, channelID, upd, cfg)
+		if err != nil {
+			return err
+		}
+		upd["config"] = merged
+	}
 	ctx, cancel := monCtx()
 	defer cancel()
 	_, err := db.Col("notification_channels").UpdateOne(ctx, bson.M{"channel_id": channelID, "instance_id": instanceID}, bson.M{"$set": upd})
 	return err
 }
 
+// mergeChannelSecrets resolves models.RedactedSecret back to what it stood for.
+//
+// The API hands out a sentinel rather than the credential, and the UI's edit
+// form round-trips whatever it was given, so an ordinary "rename this channel"
+// save arrives carrying the sentinel in place of the password. Writing it
+// through would replace the credential with eight bullet characters and break
+// delivery on the next alert. A value that is not the sentinel is written
+// verbatim — including the empty string, which is how a credential is cleared.
+func mergeChannelSecrets(instanceID, channelID string, upd bson.M, cfg map[string]string) (map[string]string, error) {
+	stored, err := GetChannel(instanceID, channelID)
+	if err != nil {
+		return nil, err
+	}
+	if stored == nil {
+		return cfg, nil
+	}
+	// The secret keys are the ones of the type being saved, which the same
+	// request may be changing.
+	channelType := stored.Type
+	if t, ok := upd["type"].(string); ok && t != "" {
+		channelType = t
+	}
+	out := make(map[string]string, len(cfg))
+	for k, v := range cfg {
+		out[k] = v
+	}
+	for _, k := range models.ChannelSecretKeys(channelType) {
+		if out[k] == models.RedactedSecret {
+			if prev, ok := stored.Config[k]; ok {
+				out[k] = prev
+			} else {
+				delete(out, k)
+			}
+		}
+	}
+	return out, nil
+}
+
 func DeleteChannel(instanceID, channelID string) error {
 	ctx, cancel := monCtx()
 	defer cancel()