Restore version check for updates on container restart

Author: thespad

root/etc/s6-overlay/s6-rc.d/init-mod-universal-calibre-setup/run

@@ -17,11 +17,18 @@ fi
 
 export DEBIAN_FRONTEND="noninteractive"
 
-if [[ ! -e /usr/bin/calibre-server ]]; then
+CALIBRE_RELEASE="$(cat /CALIBRE_RELEASE)"
+if [ -z ${CALIBRE_RELEASE+x} ]; then
+    CALIBRE_RELEASE=$(curl -sX GET "https://api.github.com/repos/kovidgoyal/calibre/releases/latest" \
+    | awk '/tag_name/{print $4;exit}' FS='[""]'); \
+fi
+
+if [[ ! -e /usr/bin/calibre-server ]] || [[ "${CALIBRE_RELEASE}" != "$(cat /config/.CALIBRE_RELEASE || :)" ]]; then
     tar xf \
         /tmp/calibre.txz \
         -C /app/calibre
     rm /tmp/calibre.txz
     echo "Installing Calibre version $(cat /CALIBRE_RELEASE)"
     /app/calibre/calibre_postinstall
+    echo "${CALIBRE_RELEASE}" > /config/.CALIBRE_RELEASE
 fi