長連接網關技術專題(四)：愛奇藝WebSocket實時推送網關技術實踐

{"type":"doc","content":[{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"本文由愛奇藝技術團隊原創分享，原題《構建通用WebSocket推送網關的設計與實踐》，有優化和改動。","attrs":{}}]},{"type":"heading","attrs":{"align":null,"level":1},"content":[{"type":"text","text":"1、引言","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"叢所周之，HTTP協議是一種無狀態、基於TCP的請求/響應模式的協議，即請求只能由客戶端發起、由服務端進行響應。在大多數場景，這種請求/響應的Pull模式可以滿足需求。但在某些情形：例如消息推送（IM中最爲常見，比如IM的離線消息推送）、實時通知等應用場景，需要實時將數據同步到客戶端，這就要求服務端支持主動Push數據的能力。","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"傳統的Web服務端推送技術歷史悠久，經歷了短輪詢、長輪詢等階段的發展（見《","attrs":{}},{"type":"link","attrs":{"href":"http://www.52im.net/thread-338-1-1.html","title":null,"type":null},"content":[{"type":"text","text":"新手入門貼：史上最全Web端即時通訊技術原理詳解","attrs":{}}]},{"type":"text","text":"》），一定程度上能夠解決問題，但也存在着不足，例如時效性、資源浪費等。HTML5標準帶來的WebSocket規範基本結束了這一局面，成爲目前服務端消息推送技術的主流方案。","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"在系統中集成WebSocket十分簡單，相關討論與資料很豐富。但如何實現一個通用的WebSocket推送網關尚未有成熟的方案。目前的雲服務廠商主要關注iOS和安卓等移動端推送，也缺少對WebSocket的支持。本文分享了愛奇藝基於Netty實現WebSocket長連接實時推送網關時的實踐經驗總結。","attrs":{}}]},{"type":"image","attrs":{"src":"https://static001.geekbang.org/infoq/0f/0f781672bdab9743e8f16d6a8b7ddcbe.png","alt":"","title":null,"style":[{"key":"width","value":"75%"},{"key":"bordertype","value":"none"}],"href":null,"fromPaste":true,"pastePass":true}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"strong","attrs":{}}],"text":"學習交流：","attrs":{}}]},{"type":"blockquote","content":[{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"- 移動端IM開發入門文章：《","attrs":{}},{"type":"link","attrs":{"href":"http://www.52im.net/thread-464-1-1.html","title":null,"type":null},"content":[{"type":"text","text":"新手入門一篇就夠：從零開發移動端IM","attrs":{}}]},{"type":"text","text":"》","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"- 開源IM框架源碼：","attrs":{}},{"type":"link","attrs":{"href":"https://github.com/JackJiang2011/MobileIMSDK","title":null,"type":null},"content":[{"type":"text","text":"https://github.com/JackJiang2011/MobileIMSDK","attrs":{}}]}]}],"attrs":{}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"（本文同步發佈於：","attrs":{}},{"type":"link","attrs":{"href":"http://www.52im.net/thread-3539-1-1.html","title":null,"type":null},"content":[{"type":"text","text":"http://www.52im.net/thread-3539-1-1.html","attrs":{}}]},{"type":"text","text":"）","attrs":{}}]},{"type":"heading","attrs":{"align":null,"level":1},"content":[{"type":"text","text":"2、專題目錄","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"strong","attrs":{}}],"text":"本文是系列文章的第4篇，總目錄如下：","attrs":{}}]},{"type":"blockquote","content":[{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"《","attrs":{}},{"type":"link","attrs":{"href":"http://www.52im.net/thread-1243-1-1.html","title":null,"type":null},"content":[{"type":"text","text":"長連接網關技術專題(一)：京東京麥的生產級TCP網關技術實踐總結","attrs":{}}]},{"type":"text","text":"》","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"《","attrs":{}},{"type":"link","attrs":{"href":"http://www.52im.net/thread-2737-1-1.html","title":null,"type":null},"content":[{"type":"text","text":"長連接網關技術專題(二)：知乎千萬級併發的高性能長連接網關技術實踐","attrs":{}}]},{"type":"text","text":"》","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"《","attrs":{}},{"type":"link","attrs":{"href":"http://www.52im.net/thread-3110-1-1.html","title":null,"type":null},"content":[{"type":"text","text":"長連接網關技術專題(三)：手淘億級移動端接入層網關的技術演進之路","attrs":{}}]},{"type":"text","text":"》","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"《","attrs":{}},{"type":"link","attrs":{"href":"http://www.52im.net/thread-3539-1-1.html","title":null,"type":null},"content":[{"type":"text","text":"長連接網關技術專題(四)：愛奇藝WebSocket實時推送網關技術實踐","attrs":{}}]},{"type":"text","text":"》（* 本文）","attrs":{}}]}],"attrs":{}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"strong","attrs":{}}],"text":"其它相關技術文章：","attrs":{}}]},{"type":"blockquote","content":[{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"《","attrs":{}},{"type":"link","attrs":{"href":"http://www.52im.net/thread-166-1-1.html","title":null,"type":null},"content":[{"type":"text","text":"絕對乾貨：基於Netty實現海量接入的推送服務技術要點","attrs":{}}]},{"type":"text","text":"》","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"《","attrs":{}},{"type":"link","attrs":{"href":"http://www.52im.net/thread-1548-1-1.html","title":null,"type":null},"content":[{"type":"text","text":"京東到家基於Netty的WebSocket應用實踐分享","attrs":{}}]},{"type":"text","text":"》","attrs":{}}]}],"attrs":{}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"strong","attrs":{}}],"text":"愛奇藝技術團隊分享的其它文章：","attrs":{}}]},{"type":"blockquote","content":[{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"《","attrs":{}},{"type":"link","attrs":{"href":"http://www.52im.net/thread-3028-1-1.html","title":null,"type":null},"content":[{"type":"text","text":"愛奇藝技術分享：輕鬆詼諧，講解視頻編解碼技術的過去、現在和將來","attrs":{}}]},{"type":"text","text":"》","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"《","attrs":{}},{"type":"link","attrs":{"href":"http://www.52im.net/thread-2221-1-1.html","title":null,"type":null},"content":[{"type":"text","text":"愛奇藝技術分享：愛奇藝Android客戶端啓動速度優化實踐總結","attrs":{}}]},{"type":"text","text":"》","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"《","attrs":{}},{"type":"link","attrs":{"href":"http://www.52im.net/thread-2981-1-1.html","title":null,"type":null},"content":[{"type":"text","text":"愛奇藝移動端網絡優化實踐分享：網絡請求成功率優化篇","attrs":{}}]},{"type":"text","text":"》","attrs":{}}]}],"attrs":{}},{"type":"heading","attrs":{"align":null,"level":1},"content":[{"type":"text","text":"3、舊方案存在的技術痛點","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"愛奇藝號是我們內容生態的重要組成，作爲前臺系統，對用戶體驗有較高要求，直接影響着創作者的創作熱情。","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"strong","attrs":{}}],"text":"目前，愛奇藝號多個業務場景中用到了WebSocket實時推送技術，包括：","attrs":{}}]},{"type":"bulletedlist","content":[{"type":"listitem","attrs":{"listStyle":null},"content":[{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"1）用戶評論：實時的將評論消息推送到瀏覽器；","attrs":{}}]}]},{"type":"listitem","attrs":{"listStyle":null},"content":[{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"2）實名認證：合同簽署前需要對用戶進行實名認證，用戶掃描二維碼後進入第三方的認證頁面，認證完成後異步通知瀏覽器認證的狀態；","attrs":{}}]}]},{"type":"listitem","attrs":{"listStyle":null},"content":[{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"3）活體識別：類似實名認證，當活體識別完成後，異步將結果通知瀏覽器。","attrs":{}}]}]}],"attrs":{}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"在實際的業務開發中，我們發現，WebSocket實時推送技術在使用中存在一些問題。","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"strong","attrs":{}}],"text":"這些問題是：","attrs":{}}]},{"type":"bulletedlist","content":[{"type":"listitem","attrs":{"listStyle":null},"content":[{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"1）首先：WebSocket技術棧不統一，既有基於Netty實現的，也有基於Web容器實現的，給開發和維護帶來困難；","attrs":{}}]}]},{"type":"listitem","attrs":{"listStyle":null},"content":[{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"2）其次：WebSocket實現分散在在各個工程中，與業務系統強耦合，如果有其他業務需要集成WebSocket，面臨着重複開發的窘境，浪費成本、效率低下；","attrs":{}}]}]},{"type":"listitem","attrs":{"listStyle":null},"content":[{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"3）第三：WebSocket是有狀態協議的，客戶端連接服務器時只和集羣中一個節點連接，數據傳輸過程中也只與這一節點通信。WebSocket集羣需要解決會話共享的問題。如果只採用單節點部署，雖然可以避免這一問題，但無法水平擴展支撐更高負載，有單點的風險；","attrs":{}}]}]},{"type":"listitem","attrs":{"listStyle":null},"content":[{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"4）最後：缺乏監控與報警，雖然可以通過Linux的Socket連接數大致評估WebSocket長連接數，但數字並不準確，也無法得知用戶數等具有業務含義的指標數據；無法與現有的微服務監控整合，實現統一監控和報警。","attrs":{}}]}]}],"attrs":{}},{"type":"paragraph","attrs":{"indent":0,"number":0,"alig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