deps(*) bump lua-resty-mlcache to 2.6.0 (#9287)

* bump lua-resty-mlcache to 2.6.0
* update changelog
* cache marshall with string.buffer
* style fix

CHANGELOG.md

@@ -288,6 +288,8 @@
   [#8845](https://github.com/Kong/kong/pull/8845)
 - Bumped penlight from 1.12.0 to 1.13.1
   [#9206](https://github.com/Kong/kong/pull/9206)
+- Bumped lua-resty-mlcache from 2.5.0 to 2.6.0
+  [#9287](https://github.com/Kong/kong/pull/9287)
 
 ### Additions
 

kong-3.0.0-0.rockspec

@@ -34,7 +34,7 @@ dependencies = {
   "lua-protobuf == 0.3.3",
   "lua-resty-worker-events == 1.0.0",
   "lua-resty-healthcheck == 1.6.1",
-  "lua-resty-mlcache == 2.5.0",
+  "lua-resty-mlcache == 2.6.0",
   "lua-messagepack == 0.5.2",
   "lua-resty-openssl == 0.8.10",
   "lua-resty-counter == 0.2.1",

kong/cache/marshall.lua

@@ -1,15 +1,23 @@
 -------------------------------------------------------------------------------
 -- NOTE: the following is copied from lua-resty-mlcache:                     --
 ------------------------------------------------------------------------ cut --
-local cjson = require "cjson.safe"
+local codec
+do
+  local pok
+  pok, codec = pcall(require, "string.buffer")
+  if not pok then
+    codec = require "cjson"
+  end
+end
 
 
 local type = type
+local pcall = pcall
 local error = error
 local tostring = tostring
 local fmt = string.format
 local now = ngx.now
-local cjson_encode = cjson.encode
+local encode = codec.encode
 
 
 local TYPES_LOOKUP = {
@@ -42,12 +50,12 @@ local marshallers = {
   end,
 
   [4] = function(t)      -- table
-      local json, err = cjson_encode(t)
-      if not json then
-          return nil, "could not encode table value: " .. err
+      local pok, str = pcall(encode, t)
+      if not pok then
+          return nil, "could not encode table value: " .. str
       end
 
-      return json
+      return str
   end,
 }