Node.js for multiplayer mobile game

[2015-05-22 Fri 17:20] speaker: Temmu Ikkonen, Technical directory of Nonstop Games event: Hackers and Painters ** why Node.js Nonstop games started as a HTML5 company used Node.js for

• templating
• low latency json API
• game logic and DB
• HTML5 EventSource and ajax long polling
• avoid threading if possible less context switch between server and client side js
• important as the company is small friends startup had Node.js in production for a year language is not as important as platform ** stability typical instance restarts 1-4 weeks busy loop programming errors most common problem ** load distribution Nginx with URL paramter based affinity Redis and Memcached for IPC one node instance serves up to 400 sessions reduce DB IO by storing log of player events in redis, flush every 30mins to mongoDB world map stored in memory, higher risk of lossing data ** node scalability most of cpu time spent in JSON parsing and serialization io scalability not a problem javascript objects are memory heavy v8 gc takes a lot of cpu when heap grows to over 350mb node-webkit-agent for debugging memory leaks main optimization is to reduce memory consumption ** deployment from version controlled dependencies instead of using npm nested configuration files based on context
• base.js -> prod.js -> prod.server1.js ** javascript async library to deal with callback hell diligent return and error handling websockets is hard to load balance,
• use HTML5 EventSource for server -> client
• ajax for client -> server ** selecting platform ask what is EASY to do, not is possible to do platform and ecosystem matters more than the language
• batters included - libraries and integration consider the roadmap of the system in addition to current features tooling predictable performance and stability ** candy crush backend MySQL and Java memcached 4TB cluster, 2M tps couple of JVM crashes every day more requests per day than google has searches InnoDB used as key-value storage blog data stored as gzipped json 50k tps for MySQL ** what next? dropping Node.js no read roadmap, politics taking over oss rarely forks and stays relevant predictable performance is questionable javascript and callback style is fragile for large teams King using Java but investigating Go and Rust Go looks promising Rust looks interesting but very immature and maybe too low level