bundles/apt: rework upgrade-and-reboot mechanics to be more robust

bundles/apt/files/do-unattended-upgrades

@@ -0,0 +1,43 @@
+#!/bin/bash
+
+set -xeuo pipefail
+
+apt-get update
+
+DEBIAN_FRONTEND=noninteractive apt-get -y -q -o Dpkg::Options::=--force-confold -o Dpkg::Options::=--force-confdef dist-upgrade
+
+DEBIAN_FRONTEND=noninteractive apt-get -y -q autoclean
+
+DEBIAN_FRONTEND=noninteractive apt-get -y -q autoremove
+
+% if clean_old_kernels:
+existing=$(dpkg --get-selections | grep -E '^linux-(image|headers)-[0-9]' || true)
+
+if [[ -z "$existing" ]]
+then
+    echo "ERROR: No installed kernels found! Aborting!" >&2
+    exit 1
+fi
+
+current=$(uname -r | sed -r 's/-[a-zA-Z]+$//')
+latest=$(echo "$existing" | sort --version-sort -t- -k 3,4 | tail -n 1 | sed -r 's/[^0-9]+([0-9]\.[^-]+-[0-9]+).*/\1/')
+todelete=$(echo "$existing" | grep -v -E "($current|$latest)" | awk '{ print $1 }' || true)
+
+if [[ -n "$todelete" ]]
+then
+    DEBIAN_FRONTEND=noninteractive apt-get -qy purge $todelete
+fi
+% endif
+
+% for affected, restarts in sorted(restart_triggers.items()):
+    up_since=$(systemctl show "${affected}" | sed -n 's/^ActiveEnterTimestamp=//p' || echo 0)
+    up_since_ts=$(date -d "$up_since" +%s || echo 0)
+    now=$(date +%s)
+
+    if [ $((now - up_since_ts)) -lt 3600 ]
+    then
+% for restart in sorted(restarts):
+        systemctl restart "${restart}" || true
+% endfor
+    fi
+% endfor