Now based on Alpine Linux and s6 as supervisor, resulting in a much smaller Docker image. See README.md for details and other additions.

root/etc/services.d/ttrss-updater/run

@@ -1,6 +1,3 @@
-#!/bin/sh
-
-while true; do
-  /srv/update-ttrss.sh
-  sleep 24h
-done
+#!/usr/bin/with-contenv sh
+sleep 24h
+exec s6-setuidgid www-data /srv/update-ttrss.sh --wait-exit 24h