fix(*): expose Bazel INSTALL_DESTDIR to Lua code and fix admin_gui in…

… dev

build/BUILD.bazel

@@ -174,7 +174,10 @@ kong_directory_genrule(
             fi
         done
         LN ${BUILD_DESTDIR}/openresty/nginx/sbin/nginx ${BUILD_DESTDIR}/openresty/bin/openresty
-    """,
+    """ + """
+        # Make INSTALL_DESTDIR available to Kong Lua code
+        echo 'return "%s/kong"' > ${BUILD_DESTDIR}/share/lua/5.1/kong/kong_usr_path.lua
+    """ % KONG_VAR["INSTALL_DESTDIR"],
     # XXX: bazel forces 0555 as artifact permission, which is not correct for packagin
     # here we deliberately use a different directory so file permission is preserved
     # see also https://github.com/bazelbuild/bazel/issues/5588

kong/cmd/utils/prefix_handler.lua

@@ -828,7 +828,11 @@ local function prepare_prefix(kong_config, nginx_custom_template_path, skip_writ
   end
 
   if kong_config.admin_gui_listeners then
-    prepare_prefixed_interface_dir("/usr/local/kong", "gui", kong_config)
+    -- kong.kong_usr_path is an AUTO GENERATED Lua module generated by BUILD.bazel
+    -- It's only used for locating the GUI directory under Kong's USR path
+    -- The module itself DOES NOT exist under <PROJECT_ROOT>/kong
+    local kong_usr_path_ok, kong_usr_path = pcall(require, "kong.kong_usr_path")
+    prepare_prefixed_interface_dir(kong_usr_path_ok and kong_usr_path or "/usr/local/kong", "gui", kong_config)
   end
 
   if secrets then