Recreate Supervisor container on OS upgrade/downgrade

When the operating system gets upgraded or downgraded the Supervisor
start script might start the Supervisor slightly differently (e.g. with
RT scheduling support). If the container has already been created, a OS
upgrade or downgrade won't recreate the Supervisor container.

buildroot-external/rootfs-overlay/usr/sbin/hassos-supervisor

@@ -11,6 +11,7 @@ set -e
 # Init supervisor
 SUPERVISOR_DATA=/mnt/data/supervisor
 SUPERVISOR_STARTUP_MARKER="/run/supervisor/startup-marker"
+SUPERVISOR_STARTSCRIPT_VERSION="${SUPERVISOR_DATA}/.hassos-supervisor-version"
 SUPERVISOR_IMAGE="homeassistant/${SUPERVISOR_ARCH}-hassio-supervisor"
 
 SUPERVISOR_IMAGE_ID=$(docker images --no-trunc --filter "reference=${SUPERVISOR_IMAGE}:latest" --format "{{.ID}}" || echo "")
@@ -55,11 +56,21 @@ if [ -z "${SUPERVISOR_IMAGE_ID}" ]; then
     SUPERVISOR_IMAGE_ID=$(docker inspect --format='{{.Id}}' "${SUPERVISOR_IMAGE}" || echo "")
 fi
 
-# Image changed, remove previous container
-if [ -n "${SUPERVISOR_CONTAINER_ID}" ] && [ "${SUPERVISOR_IMAGE_ID}" != "${SUPERVISOR_CONTAINER_ID}" ]; then
-    echo "[INFO] Supervisor image has been updated, destroying previous container..."
-    docker container rm --force hassio_supervisor || true
-    SUPERVISOR_CONTAINER_ID=""
+if [ -n "${SUPERVISOR_CONTAINER_ID}" ]; then
+    # Image changed, remove previous container
+    if [ "${SUPERVISOR_IMAGE_ID}" != "${SUPERVISOR_CONTAINER_ID}" ]; then
+        echo "[INFO] Supervisor image has been updated, destroying previous container..."
+        docker container rm --force hassio_supervisor || true
+        SUPERVISOR_CONTAINER_ID=""
+    fi
+
+    # Start script changed, remove previous container
+    # shellcheck disable=SC3013
+    if [ ! -f "${SUPERVISOR_STARTSCRIPT_VERSION}" ] || [ "${SUPERVISOR_STARTSCRIPT_VERSION}" -nt "$0" ] || [ "${SUPERVISOR_STARTSCRIPT_VERSION}" -ot "$0" ]; then
+        echo "[INFO] Supervisor start script has changed, destroying previous container..."
+        docker container rm --force hassio_supervisor || true
+        SUPERVISOR_CONTAINER_ID=""
+    fi
 fi
 
 # If Supervisor container is missing, create it
@@ -80,6 +91,10 @@ if [ -z "${SUPERVISOR_CONTAINER_ID}" ]; then
         -e SUPERVISOR_CPU_RT=1 \
         -e SUPERVISOR_MACHINE=${SUPERVISOR_MACHINE} \
         "${SUPERVISOR_IMAGE}:latest"
+
+    # Store the timestamp of this script. If the script changed, let's
+    # recreate the container automatically.
+    touch --reference="$0" "${SUPERVISOR_STARTSCRIPT_VERSION}"
 fi
 
 # Run supervisor