fix(installer): only setup nginx on first install

Users usually want to setup a ssl certificate for LibreTime. Disabling any nginx config change unless it is the first install should prevent breaking a possible certbot setup.

install

@@ -73,6 +73,8 @@ Options:
   --no-setup-postgresql         Do not setup Postgresql.
   --no-setup-rabbitmq           Do not setup RabbitMQ.
 
+  --update-nginx                Update nginx files during upgrades.
+
 Environment variables:
 
   Advanced options can be changed using environment variables (flags will take
@@ -113,6 +115,9 @@ LIBRETIME_SETUP_POSTGRESQL=${LIBRETIME_SETUP_POSTGRESQL:-true}
 # > Create a default rabbitmq user with a random password.
 LIBRETIME_SETUP_RABBITMQ=${LIBRETIME_SETUP_RABBITMQ:-true}
 
+# > Update nginx files during upgrades.
+LIBRETIME_UPDATE_NGINX=${LIBRETIME_UPDATE_NGINX:-false}
+
 # > Comma separated list of sections to exclude from packages list.
 LIBRETIME_PACKAGES_EXCLUDES=${LIBRETIME_PACKAGES_EXCLUDES:-}
 
@@ -130,6 +135,10 @@ while [[ $# -gt 0 ]]; do
       LIBRETIME_INSTALL_IN_PLACE=true
       shift 1
       ;;
+    --update-nginx)
+      LIBRETIME_UPDATE_NGINX=true
+      shift 1
+      ;;
     --no-setup-icecast)
       LIBRETIME_SETUP_ICECAST=false
       shift 1
@@ -730,23 +739,35 @@ template_file cp_if_different \
 
 section "Nginx"
 
-install_packages nginx
+if $is_first_install || $LIBRETIME_UPDATE_NGINX; then
+  install_packages nginx
 
-info "disabling nginx default site"
-rm -f "/etc/nginx/sites-enabled/default"
+  info "disabling nginx default site"
+  rm -f "/etc/nginx/sites-enabled/default"
+fi
 
-info "deploying libretime nginx config"
-template_file cp_if_different \
-  "${SCRIPT_DIR}/installer/nginx/libretime.conf" \
-  "/etc/nginx/sites-available/libretime.conf" \
-  sed \
-    -e "s|@@LISTEN_PORT@@|${LIBRETIME_LISTEN_PORT}|g" \
+nginx_config_template_args=(
+  "${SCRIPT_DIR}/installer/nginx/libretime.conf"
+  "/etc/nginx/sites-available/libretime.conf"
+    sed
+    -e "s|@@LISTEN_PORT@@|${LIBRETIME_LISTEN_PORT}|g"
     -e "s|@@LEGACY_WEB_ROOT@@|${LEGACY_WEB_ROOT}|g"
+)
 
-info "enabling libretime nginx config"
-ln -s --force \
-  "/etc/nginx/sites-available/libretime.conf" \
-  "/etc/nginx/sites-enabled/libretime.conf"
+if $is_first_install || $LIBRETIME_UPDATE_NGINX; then
+  info "deploying libretime nginx config"
+  template_file cp_if_different "${nginx_config_template_args[@]}"
+else
+  info "printing libretime nginx config differences"
+  template_file diff_if_exists "${nginx_config_template_args[@]}"
+fi
+
+if $is_first_install || $LIBRETIME_UPDATE_NGINX; then
+  info "enabling libretime nginx config"
+  ln -s --force \
+    "/etc/nginx/sites-available/libretime.conf" \
+    "/etc/nginx/sites-enabled/libretime.conf"
+fi
 
 # Finalize
 ########################################################################################