Files
nixconfig/packages/jellyfin-mpv-shim-watchdog/default.nix
T
2026-08-19 20:18:38 +02:00

52 lines
2.2 KiB
Nix

{ writeShellScriptBin
, coreutils
, findutils
, gnugrep
, iproute2
, systemd
}:
# jellyfin-mpv-shim keeps a persistent socket to the Jellyfin server. When the
# machine drops off the network that socket dies, but the process stays alive
# and the unit stays "active" — running yet deaf to cast requests, the "up but
# not working, restart it by hand" case. systemd can't see this: nothing
# crashes and the shim speaks no health protocol, so we probe the real thing —
# is its MainPID still holding a live (established, non-loopback) connection?
#
# check (default) one tick, run by a 60s timer: restart if online but
# not connected, rate-limited to one restart per 5 min
# wait-online block until a real address exists; used as ExecStartPre so the
# unit only starts once online
writeShellScriptBin "jellyfin-mpv-shim-watchdog" ''
set -u
service="jellyfin-mpv-shim.service"
stamp="''${XDG_RUNTIME_DIR:-/run/user/$(${coreutils}/bin/id -u)}/jellyfin-mpv-shim-watchdog.stamp"
# A global-scope address on a non-loopback interface — true for a LAN IP too,
# so this needs no server URL and works whether Jellyfin is local or remote.
network_up() { ${iproute2}/bin/ip -o addr show scope global up 2>/dev/null | ${gnugrep}/bin/grep -q .; }
if [ "''${1:-check}" = wait-online ]; then
while ! network_up; do ${coreutils}/bin/sleep 5; done
exit 0
fi
# Healthy: MainPID owns an established socket to something other than loopback.
pid="$(${systemd}/bin/systemctl --user show -p MainPID --value "$service" 2>/dev/null)"
if [ "''${pid:-0}" != 0 ] && ${iproute2}/bin/ss -tnpH state established 2>/dev/null \
| ${gnugrep}/bin/grep "pid=$pid," \
| ${gnugrep}/bin/grep -qv -e '127\.0\.0\.1' -e '\[::1\]'; then
exit 0
fi
# Not connected: only worth restarting once the network is actually back...
network_up || exit 0
# ...and not if we already restarted within the last 5 minutes.
[ -e "$stamp" ] && [ -n "$(${findutils}/bin/find "$stamp" -mmin -5 2>/dev/null)" ] && exit 0
: > "$stamp"
echo "jellyfin-mpv-shim-watchdog: online but no live connection -> restarting $service"
${systemd}/bin/systemctl --user restart "$service"
''