【基于skyent的热更思考】

基于skyent的热更思考

skynet-inject热更原理
关键源码分析
热更方式
拓扑图
注意事项

skynet-inject热更原理

inject是一个用于动态加载 Lua 代码文件并执行其中定义的函数的功能。可以在运行时动态加载 Lua 代码文件，然后调用其中定义的函数，通过修改模块及其函数的upvalue，实现代码的动态注入和执行。热更实现的大概思路：通过向指定服务注入cmd实现热更
参考wiki https://blog.codingnow.com/2016/11/lua_update.html

关键源码分析

-- debug_console.lualocal function adjust_address(address)local prefix = address:sub(1,1)if prefix == '.' thenreturn assert(skynet.localname(address), "Not a valid name")elseif prefix ~= ':' thenaddress = assert(tonumber("0x" .. address), "Need an address") | (skynet.harbor(skynet.self()) << 24)endreturn address
endfunction COMMAND.inject(address, filename, ...)address = adjust_address(address)local f = io.open(filename, "rb")if not f thenreturn "Can't open " .. filenameendlocal source = f:read "*a"f:close()local ok, output = skynet.call(address, "debug", "RUN", source, filename, ...)if ok == false thenerror(output)endreturn output
end

adjust_address: 用于调整传入的地址参数，对传入的地址参数进行转换,以保证将热更脚本注入到正确的服务地址
io.open(filename, “rb”): 以二进制只读的方式读取文件内容
source: 存放读取到的热更脚本内容
skynet.call(address, “debug”, “RUN”, …): 通过skynet的debug消息类型，将读取的热更脚本内容注入到目标服务地址(debug.RUN内部实现)

-- skynet.debug.luafunction dbgcmd.RUN(source, filename, ...)local inject = require "skynet.inject"local args = table.pack(...)local ok, output = inject(skynet, source, filename, args, export.dispatch, skynet.register_protocol)collectgarbage "collect"skynet.ret(skynet.pack(ok, table.concat(output, "\n")))
end

-- skynet.inject.luareturn function(skynet, source, filename, args, ...)if filename thenfilename = "@" .. filenameelsefilename = "=(load)"endlocal output = {}local function print(...)local value = { ... }for k,v in ipairs(value) dovalue[k] = tostring(v)endtable.insert(output, table.concat(value, "\t"))endlocal u = {}local unique = {}local funcs = { ... }for k, func in ipairs(funcs) dogetupvaluetable(u, func, unique)endlocal p = {}local proto = u.protoif proto thenfor k,v in pairs(proto) dolocal name, dispatch = v.name, v.dispatchif name and dispatch and not p[name] thenlocal pp = {}p[name] = ppgetupvaluetable(pp, dispatch, unique)endendendlocal env = setmetatable( { print = print , _U = u, _P = p}, { __index = _ENV })local func, err = load(source, filename, "bt", env)if not func thenreturn false, { err }endlocal ok, err = skynet.pcall(func, table.unpack(args, 1, args.n))if not ok thentable.insert(output, err)return false, outputendreturn true, output
end