feat(lua-client): 新增 Lua 客户端 SDK 及示例

kenaito-conf-lua-client/kenaito_conf/cache.lua

@@ -0,0 +1,41 @@
+local json = require("dkjson")
+
+local Cache = {}
+Cache.__index = Cache
+
+local CACHE_FILE = "config-cache.json"
+
+function Cache.new(cache_dir)
+    local self = setmetatable({}, Cache)
+    self.cache_dir = cache_dir or "."
+    return self
+end
+
+function Cache:write(data)
+    local path = self.cache_dir .. "/" .. CACHE_FILE
+    local file = io.open(path, "w")
+    if not file then
+        return false, "cannot open cache file: " .. path
+    end
+    local str = json.encode(data, { indent = true })
+    file:write(str)
+    file:close()
+    return true
+end
+
+function Cache:read()
+    local path = self.cache_dir .. "/" .. CACHE_FILE
+    local file = io.open(path, "r")
+    if not file then
+        return nil, "cache file not found"
+    end
+    local str = file:read("*a")
+    file:close()
+    local data, _, err = json.decode(str)
+    if err then
+        return nil, "json decode error: " .. err
+    end
+    return data
+end
+
+return Cache