Better graphical start

2026-09-11 14:28:11 +02:00
parent b7cfc63310
commit 07b7e2bb05
13 changed files with 152 additions and 99 deletions
@@ -0,0 +1,69 @@
+{ writeShellScriptBin
+, coreutils
+, findutils
+, gnugrep
+, iproute2
+, systemd
+}:
+
+# For user services that only make sense while online (jellyfin-mpv-shim,
+# nextcloud-client, ...). They keep a persistent socket to their server; when
+# the machine drops off the network that socket dies, but the process stays
+# alive and the unit stays "active" — running yet deaf, the "up but not
+# working, restart it by hand" case. systemd can't see this: nothing crashes
+# and the programs speak no health protocol, so we probe the real thing — is
+# the MainPID still holding a live (established, non-loopback) connection?
+#
+#   wait-online UNIT  block until a real address exists; used as ExecStartPre
+#                     so UNIT only starts once online. Also stamps the start
+#                     time so `check` leaves a freshly (re)started UNIT alone.
+#   check UNIT...     one tick, run by a 60s timer: restart every UNIT that is
+#                     active but not connected, at most once per 5 minutes.
+#
+# Wired up by the services.network-watchdog home-manager module.
+
+writeShellScriptBin "network-watchdog" ''
+  set -u
+  stampdir="''${XDG_RUNTIME_DIR:-/run/user/$(${coreutils}/bin/id -u)}/network-watchdog"
+  ${coreutils}/bin/mkdir -p "$stampdir"
+
+  usage() { echo "usage: network-watchdog wait-online UNIT | check UNIT..." >&2; exit 64; }
+
+  # A global-scope address on a non-loopback interface — true for a LAN IP too,
+  # so this needs no server URL and works whether the server is local or remote.
+  network_up() { ${iproute2}/bin/ip -o addr show scope global up 2>/dev/null | ${gnugrep}/bin/grep -q .; }
+
+  # Healthy: MainPID owns an established socket to something other than loopback.
+  connected() {
+    pid="$(${systemd}/bin/systemctl --user show -p MainPID --value "$1" 2>/dev/null)"
+    [ "''${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 '\[::1\]'
+  }
+
+  # Stamped within the last 5 minutes: still connecting, or already restarted.
+  recently_started() { [ -n "$(${findutils}/bin/find "$stampdir/$1" -mmin -5 2>/dev/null)" ]; }
+
+  [ $# -ge 1 ] || usage
+  cmd="$1"; shift
+  case "$cmd" in
+    wait-online)
+      [ $# -eq 1 ] || usage
+      while ! network_up; do ${coreutils}/bin/sleep 5; done
+      : > "$stampdir/$1"
+      ;;
+    check)
+      # Nothing can be connected while offline, and restarting wouldn't help.
+      network_up || exit 0
+      for unit; do
+        # Not "active" (inactive, failed, or still in wait-online): systemd's job, not ours.
+        ${systemd}/bin/systemctl --user is-active --quiet "$unit" || continue
+        recently_started "$unit" && continue
+        connected "$unit" && continue
+        echo "network-watchdog: $unit is online but has no live connection -> restarting"
+        ${systemd}/bin/systemctl --user restart "$unit"  # its wait-online refreshes the stamp
+      done
+      ;;
+    *) usage ;;
+  esac
+''