Live Nginx (re)configuration without reloading (#2174)

rootfs/etc/nginx/lua/util.lua

@@ -0,0 +1,27 @@
+local _M = {}
+
+-- this implementation is taken from
+-- https://web.archive.org/web/20131225070434/http://snippets.luacode.org/snippets/Deep_Comparison_of_Two_Values_3
+-- and modified for use in this project
+local function deep_compare(t1, t2, ignore_mt)
+  local ty1 = type(t1)
+  local ty2 = type(t2)
+  if ty1 ~= ty2 then return false end
+  -- non-table types can be directly compared
+  if ty1 ~= 'table' and ty2 ~= 'table' then return t1 == t2 end
+  -- as well as tables which have the metamethod __eq
+  local mt = getmetatable(t1)
+  if not ignore_mt and mt and mt.__eq then return t1 == t2 end
+  for k1,v1 in pairs(t1) do
+    local v2 = t2[k1]
+    if v2 == nil or not deep_compare(v1,v2) then return false end
+  end
+  for k2,v2 in pairs(t2) do
+    local v1 = t1[k2]
+    if v1 == nil or not deep_compare(v1,v2) then return false end
+  end
+  return true
+end
+_M.deep_compare = deep_compare
+
+return _M