From f0987ccb44fd2b7575c0f2b3e33df07d366d49b9 Mon Sep 17 00:00:00 2001
From: Franziska Kunsmann <hi@kunsmann.eu>
Date: Thu, 19 Aug 2021 20:03:24 +0200
Subject: [PATCH] bundles/unbound: automatically restart unbound if dns
 resolution fails for more than five minutes

---
 bundles/unbound/files/unbound-auto-restart | 25 ++++++++++++++++++++++
 bundles/unbound/items.py                   |  3 +++
 bundles/unbound/metadata.py                |  1 +
 3 files changed, 29 insertions(+)
 create mode 100644 bundles/unbound/files/unbound-auto-restart

diff --git a/bundles/unbound/files/unbound-auto-restart b/bundles/unbound/files/unbound-auto-restart
new file mode 100644
index 0000000..b2a82d2
--- /dev/null
+++ b/bundles/unbound/files/unbound-auto-restart
@@ -0,0 +1,25 @@
+#!/bin/bash
+
+now="$(date +%s)"
+
+resolved="$(dig +short kunbox.net)"
+
+if [[ -n "$resolved" ]]
+then
+    echo "$now" > /var/tmp/unbound_last_resolved
+    exit 0
+fi
+
+last_resolved="$(cat /var/tmp/unbound_last_resolved)"
+five_min_ago="$(expr $now - 300)"
+
+if [[ "$last_resolved" -lt "$five_min_ago" ]]
+then
+    systemctl restart unbound
+
+    # Write "in 25 minutes" timestamp to /var/tmp/unbound_last_resolved.
+    # If resolving gets fixed by the restart, this will get re-written
+    # on the next run of this script. If not, this script will restart
+    # unbound again in half an hour (25min plus 5min grace time).
+    echo "$(expr $now + 1500)" > /var/tmp/unbound_last_resolved
+fi
diff --git a/bundles/unbound/items.py b/bundles/unbound/items.py
index fdd1a18..519b811 100644
--- a/bundles/unbound/items.py
+++ b/bundles/unbound/items.py
@@ -6,6 +6,9 @@ files = {
             'svc_systemd:unbound:restart',
         },
     },
+    '/usr/local/sbin/unbound-auto-restart': {
+        'mode': '0755',
+    },
 }
 
 actions = {
diff --git a/bundles/unbound/metadata.py b/bundles/unbound/metadata.py
index caf3d04..4a27851 100644
--- a/bundles/unbound/metadata.py
+++ b/bundles/unbound/metadata.py
@@ -13,6 +13,7 @@ defaults = {
             node.magic_number%24,
             node.magic_number%7,
         ),
+        'unbound-auto-restart': '* * * * *    root    /usr/local/sbin/unbound-auto-restart',
     },
     'nameservers': {
         '127.0.0.1',