improvements to configure

configure.d/15-tailscale.sh

@@ -14,12 +14,45 @@ is_installed() {
 
 # Tailscale has no status field naming its login server, so tailscale.conf
 # records which Core it was set up for
-is_configured() {
-  [ -n "$CORE_DOMAIN" ] && [ "$TAILSCALE_DOMAIN" = "$CORE_DOMAIN" ] \
+joined() {
+  [ -n "$TAILSCALE_DOMAIN" ] \
     && tailscale status --json 2> /dev/null | jq -e '.BackendState == "Running"' > /dev/null
 }
 
+# Done when on the main Core's network
+is_configured() {
+  [ -n "$CORE_DOMAIN" ] && [ "$TAILSCALE_DOMAIN" = "$CORE_DOMAIN" ] && joined
+}
+
+# Log out rather than only go down, so this computer's key is expired on
+# headscale and it's off the network until it joins again
+leave_network() {
+  sudo tailscale logout || return 1
+  rm -f "$TAILSCALE_CONF"
+  echo "This computer has left your Core's Tailscale network. To join again: configure tailscale"
+}
+
 run_configure() {
+  local choice
+  if joined &> /dev/null; then
+    echo "This computer is on $TAILSCALE_DOMAIN's Tailscale network (headscale.$TAILSCALE_DOMAIN)."
+    echo
+    if [ "$TAILSCALE_DOMAIN" = "$CORE_DOMAIN" ]; then
+      echo "  1) Join it again"
+    else
+      echo "  1) Join your main Core's network instead (headscale.$CORE_DOMAIN)"
+    fi
+    echo "  2) Leave the network"
+    echo "  q) Leave it as it is"
+    echo
+    read -rp "Choose: " choice
+    case "$choice" in
+      1) ;;
+      2) leave_network; return ;;
+      *) return 0 ;;
+    esac
+  fi
+
   if [ -z "$CORE_DOMAIN" ]; then
     echo "This joins your Core's Tailscale network, so set up your Core first: configure core"
     return 1