tunnel, restart the service if the remote host no longer forwards to the local process.

tasks/general/settings/tunnel.yml

@@ -17,6 +17,20 @@
   ansible.builtin.set_fact:
     tunnel_service_name: tunnel
 
+- name: General | Tunnel | Packages [pacman]
+  ansible.builtin.package:
+    name:
+      - openbsd-netcat
+    state: present
+  when: ansible_pkg_mgr == "pacman"
+
+- name: General | Tunnel | Packages [apt]
+  ansible.builtin.package:
+    name:
+      - netcat-openbsd
+    state: present
+  when: ansible_pkg_mgr == "apt"
+
 - name: General | Tunnel | runit
   block:
 
@@ -38,7 +52,22 @@
         content: |
           #!/bin/sh -e
           exec 2>&1
-          exec chpst -u {{ user }} ssh -v -N \
+
+          # Health check to ensure connection does not go stale.
+          (
+            while true; do
+              sleep 300
+              nc -zv {{ tunnel_remote_host }} {{ tunnel_remote_port }} >/dev/null 2>&1
+              status="$?"
+              if [[ "$status" != 0 ]]; then
+                echo "RUN: Port check returned $status, restarting service."
+                sv restart {{ tunnel_service_name }}
+              fi
+            done
+          ) &
+
+          # Do not use `exec` here otherwise the loop may get killed.
+          chpst -u {{ user }} ssh -v -N \
             -R {{ tunnel_remote_port }}:localhost:{{ tunnel_local_port }} \
             -p {{ tunnel_ssh_port }} {{ tunnel_remote_host }}
         mode: "0755"