music-assistant: Tell players to restart on startup

I haven't fully determined why, but when the Music Assistant server
restarts, it marks the _shairport-sync_ players as offline and will not
allow playing to them.  The only way I have found to work around this is
to restart the players after the server restarts.  As that's pretty
cumbersome and annoying, I naturally want to automate it, so I've
created this rudimentary synchronization technique using _ntfy_: each
player listens for notifications on a specific topic, and upon receiving
one, tells _shairport-sync_ to exit.  With the `Restart=` property
configured on the _shairport-sync.service_ unit, _systemd_ will restart
the service, which causes Music Assistant to discover the player again.

music-assistant/kustomization.yaml

@@ -16,6 +16,25 @@ resources:
 - music-assistant.yaml
 - ingress.yaml
 
+patches:
+- patch: |
+    apiVersion: apps/v1
+    kind: StatefulSet
+    metadata:
+      name: music-assistant
+    spec:
+      template:
+        spec:
+          containers:
+          - name: music-assistant
+            lifecycle:
+              postStart:
+                exec:
+                  command:
+                  - wget
+                  - -qO-
+                  - http://ntfy.ntfy:2586/0e386416-ac43-488c-b709-efac8e2555a3/publish?message=restart
+
 images:
 - name: ghcr.io/music-assistant/server
   newTag: 2.6.0b18

music-assistant/restart-sync.service

@@ -0,0 +1,22 @@
+# vim: set ft=systemd :
+
+# In order for this to be effective, `shairport-sync.service` needs a
+# configuration override to enable auto-restart, e.g.:
+#
+# [Service]
+# Restart=always
+# RestartSec=1
+
+[Unit]
+Description=Restart shairport-sync when music-assistant restarts
+Wants=network-online.target
+After=network-online.target
+
+[Service]
+Type=simple
+ExecStart=/usr/local/libexec/restart-sync.sh
+Restart=always
+RestartSec=1
+
+[Install]
+WantedBy=shairport-sync.service

music-assistant/restart-sync.sh

@@ -0,0 +1,15 @@
+#!/bin/sh
+
+TOPIC=0e386416-ac43-488c-b709-efac8e2555a3
+NTFY=https://ntfy.pyrocufflink.net
+DELAY=10
+
+url=$(printf '%s/%s/raw' "${NTFY}" "${TOPIC}")
+
+curl -sN "${url}" \
+	| stdbuf -o0 grep restart \
+	| while read l; do
+printf 'Restarting shairport-sync in %d seconds\n' "$DELAY" >&2
+sleep $DELAY
+busctl call org.gnome.ShairportSync /org/gnome/ShairportSync org.gnome.ShairportSync Quit
+done