Add HEALTHCHECK support

tailscale/DOCS.md

@@ -70,6 +70,7 @@ advertise_routes:
   - 192.168.1.0/24
   - fd12:3456:abcd::/64
 funnel: false
+healthcheck_timeout: 110
 log_level: info
 login_server: "https://controlplane.tailscale.com"
 proxy: false
@@ -189,6 +190,25 @@ port 443 (or the port configured in option `proxy_and_funnel_port`)._
 **Note:** _If you encounter strange browser behaviour or strange error messages,
 try to clear all site related cookies, clear all browser cache, restart browser._
 
+### Option: `healthcheck_timeout`
+
+This option allows you to set timeout in seconds for Tailscale to be offline.
+
+When not set, this option is disabled by default.
+
+Tailscale is quite resilient and can recover from nearly any network change. But
+in case it fails to recover and remains offline longer than healthcheck_timeout
+seconds, the add-on can be restarted. The check happens only when Tailscale is
+running, ie. it won't have any effect when Tailscale's status is eg. Starting,
+NeedsLogin or NeedsMachineAuth.
+
+The Stopped status is deemed unhealthy by default.
+
+**Note:** _If the network is down, the add-on will be restarted only once._
+
+**Note:** _The add-on's health is checked by Home Assistant in each 30s, ie. the
+effective resolution of this option is 30s, not 1s._
+
 ### Option: `log_level`
 
 Optionally enable tailscaled debug messages in the add-on's log. Turn it on only

tailscale/Dockerfile

@@ -35,6 +35,9 @@ RUN \
 # Copy root filesystem
 COPY rootfs /
 
+HEALTHCHECK \
+    CMD healthcheck
+
 # S6 Overlay stage 2 hook
 ENV S6_STAGE2_HOOK=/etc/s6-overlay/scripts/stage2_hook.sh
 

tailscale/config.yaml

@@ -35,6 +35,7 @@ schema:
   advertise_routes:
     - "match(^(((25[0-5]|(2[0-4]|1\\d|[1-9]?)\\d)\\.){3}(25[0-5]|(2[0-4]|1\\d|[1-9]?)\\d)\\/(3[0-2]|[12]?\\d)|[a-fA-F\\d.:]+:[a-fA-F\\d.:]+\\/(12[0-8]|(1[01]|[1-9]?)\\d))$)?"
   funnel: bool?
+  healthcheck_timeout: int?
   log_level: list(trace|debug|info|notice|warning|error|fatal)?
   login_server: url?
   proxy: bool?

tailscale/rootfs/etc/s6-overlay/s6-rc.d/post-tailscaled/run

@@ -90,7 +90,7 @@ unset IFS
 # Wait for the network to be available and logged in
 while ! bashio::fs.socket_exists "/var/run/tailscale/tailscaled.sock" || \
   ! /opt/tailscale status --json --peers=false --self=false \
-    | jq --exit-status '.BackendState == "Running" or .BackendState == "NeedsLogin"' > /dev/null;
+    | jq --exit-status '.BackendState == "Running" or .BackendState == "NeedsLogin" or .BackendState == "Stopped"' > /dev/null;
 do
   sleep 2
 done

tailscale/rootfs/usr/bin/healthcheck

@@ -0,0 +1,30 @@
+#!/command/with-contenv bashio
+# shellcheck shell=bash
+
+# Plain (non-json) tailscale status returns error when status is not Running or Starting, so eg. NeedsLogin and NeedsMachineAuth would make it unhealthy
+# The .Health json filter returns any problems, so even temporary health problems would make it unhealthy
+# This script treats the following situations unhealthy:
+# - always: .BackendState == "Stopped"
+# - optionally: .BackendState == "Running" && .Self.Online == false for more then healthcheck_timeout seconds (configurable)
+#   This can handle internal TS bugs, like https://github.com/tailscale/tailscale/issues/12021 where TS fails to recover from rerouting traffic from normal WAN to failover WAN
+
+declare status_json
+declare backend_state self_online
+# LAST_ONLINE_TIMESTAMP is in contenv at /var/run/s6/container_environment
+
+status_json=$(/opt/tailscale status --json --self=true --peers=false)
+backend_state=$(jq -r '.BackendState' <<< "${status_json}")
+self_online=$(jq -r '.Self.Online' <<< "${status_json}")
+
+if bashio::var.equals "${backend_state}" "Running" && bashio::var.equals "${self_online}" "true"; then
+  LAST_ONLINE_TIMESTAMP=$(date +"%s")
+  printf "${LAST_ONLINE_TIMESTAMP}" > /var/run/s6/container_environment/LAST_ONLINE_TIMESTAMP
+fi
+
+if [[ "${backend_state}" == "Stopped" ]] || \
+  bashio::config.has_value "healthcheck_timeout" && \
+    bashio::var.has_value "${LAST_ONLINE_TIMESTAMP-}" && \
+    (( $(date +"%s") - ${LAST_ONLINE_TIMESTAMP} > $(bashio::config "healthcheck_timeout") ))
+then
+  exit 1
+fi

tailscale/translations/en.yaml

@@ -41,6 +41,11 @@ configuration:
       Home Assistant instance on the wider internet using your Tailscale domain.
       This requires Tailscale Proxy to be enabled.
       When not set, this option is disabled by default.
+  healthcheck_timeout:
+    name: Healthcheck timeout [s]
+    description: >-
+      This option allows you to set timeout in seconds for Tailscale to be offline.
+      When not set, this option is disabled by default.
   log_level:
     name: Log level
     description: >-