結合阿里雲 FC 談談我對 FaaS 的理解

{"type":"doc","content":[{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"進入主題之前，先從背景簡述下最近前端界的熱點詞彙 Serverless，其實，Serverless 這個概念在其他領域已經提出來很久了。"}]},{"type":"heading","attrs":{"align":null,"level":2},"content":[{"type":"text","text":"Serverless"}]},{"type":"heading","attrs":{"align":null,"level":3},"content":[{"type":"text","text":"概念"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"Serverless 直譯爲無服務器，代表一種"},{"type":"text","marks":[{"type":"strong"}],"text":"無服務器架構"},{"type":"text","text":"（也被稱爲“"},{"type":"text","marks":[{"type":"strong"}],"text":"無服務器計算"},{"type":"text","text":"”），並不表示不需要物理服務器，而是指不需要關注和管理服務器，直接使用服務即可，其實就是一種"},{"type":"text","marks":[{"type":"strong"}],"text":"服務外包"},{"type":"text","text":"或者說"},{"type":"text","marks":[{"type":"strong"}],"text":"服務託管"},{"type":"text","text":"，這些服務由第三方供應商提供。"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"具體來說，Serverless 就是指服務端邏輯由開發者實現，運行在無狀態的計算容器中，由"},{"type":"text","marks":[{"type":"strong"}],"text":"事件驅動"},{"type":"text","text":"，完全"},{"type":"text","marks":[{"type":"strong"}],"text":"被第三方管理"},{"type":"text","text":"，而業務層面的狀態則記錄在"},{"type":"text","marks":[{"type":"strong"}],"text":"數據庫或存儲資源"},{"type":"text","text":"中。"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"目前國內一些大型公司如阿里、騰訊、滴滴都已經將 Serverless 逐步在業務中落地（案例分享："},{"type":"text","marks":[{"type":"strong"}],"text":"2020.06.19 ServerlessDays · China Online"},{"type":"text","text":" (https:\/\/cloud.tencent.com\/developer\/salon\/live-1224)）。"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"heading","attrs":{"align":null,"level":3},"content":[{"type":"text","text":"Serverless 與 FaaS 的聯繫"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"Serverless = "},{"type":"text","marks":[{"type":"strong"}],"text":"FaaS + BaaS"},{"type":"text","text":" ，是目前界內比較公認的定義："}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"bulletedlist","content":[{"type":"listitem","attrs":{"listStyle":null},"content":[{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"FaaS（Function as a Service）：函數即服務"}]}]},{"type":"listitem","attrs":{"listStyle":null},"content":[{"type":"paragraph","attrs":{"indent":1,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"負責"},{"type":"text","marks":[{"type":"strong"}],"text":"服務端業務邏輯場景"},{"type":"text","text":"，需要開發者自己實現，服務的粒度比微服務更小，小到以函數爲單位"}]}]},{"type":"listitem","attrs":{"listStyle":null},"content":[{"type":"paragraph","attrs":{"indent":1,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"strong"}],"text":"事件驅動"},{"type":"text","text":"的 Serverless 服務，毫秒級彈性伸縮"}]}]},{"type":"listitem","attrs":{"listStyle":null},"content":[{"type":"paragraph","attrs":{"indent":1,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"無法進行內存或數據共享，是"},{"type":"text","marks":[{"type":"strong"}],"text":"無狀態的"}]}]},{"type":"listitem","attrs":{"listStyle":null},"content":[{"type":"paragraph","attrs":{"indent":1,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"strong"}],"text":"無需運維"},{"type":"text","text":"，部署、運維等都由雲平臺提供"}]}]},{"type":"listitem","attrs":{"listStyle":null},"content":[{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"BaaS（Backend as Service）：後端即服務"}]}]}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"image","attrs":{"src":"https:\/\/static001.geekbang.org\/infoq\/e1\/e139bf73ebf8d53dc3b244231163bb01.png","alt":"Image","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}},{"type":"bulletedlist","content":[{"type":"listitem","attrs":{"listStyle":null},"content":[{"type":"paragraph","attrs":{"indent":1,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"負責"},{"type":"text","marks":[{"type":"strong"}],"text":"通用服務場景"},{"type":"text","text":"，不需要開發者自己開發，由雲廠商提供，比如數據庫、身份驗證、消息隊列、對象存儲等服務"}]}]},{"type":"listitem","attrs":{"listStyle":null},"content":[{"type":"paragraph","attrs":{"indent":1,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"是"},{"type":"text","marks":[{"type":"strong"}],"text":"有狀態"},{"type":"text","text":"的"}]}]}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"筆者認爲，單看 FaaS 或者 BaaS，都是一種 Serverless ，只是一般我們完整的應用需要兩者結合才能實現。"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"好，下面正式介紹 FaaS。"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"heading","attrs":{"align":null,"level":2},"content":[{"type":"text","text":"FaaS"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"作爲一個前端，我們平日裏很難接觸到服務器、運維方面的操作。假設現在給你一個任務，讓你自己開發一個有前後端交互的應用，並從 0 到 1 進行部署，是不是覺得光靠自己根本搞不定，這個任務有點難。"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"傳統應用的部署，我們需要做很多工作：準備服務器、配置環境、購買域名、配置 Nginx、……。應用發佈之後，我們還要考慮運維的問題，線上監控，擴縮容，容災等等等等。"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"現在，我們運用 FaaS 去開發部署的話，以上都不用考慮，只需要專注於業務邏輯開發即可，因爲"},{"type":"text","marks":[{"type":"strong"}],"text":"其它一切都託管給 FaaS 平臺"},{"type":"text","text":"幫我們處理了。"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"heading","attrs":{"align":null,"level":3},"content":[{"type":"text","text":"概念"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"FaaS  是無服務器計算的一種形式。通過 FaaS，可以快速構建任何類型的應用和服務，它具有開發敏捷特性、自動彈性伸縮能力、免運維和完善的監控設施。因此："}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"bulletedlist","content":[{"type":"listitem","attrs":{"listStyle":null},"content":[{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"開發者只需專注於業務邏輯開發，無需管理服務器、運行環境等 IT 基礎設施"}]}]},{"type":"listitem","attrs":{"listStyle":null},"content":[{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"FaaS 平臺會爲我們準備好計算資源，以彈性、可靠的方式運行我們的代碼，實現毫秒級"},{"type":"text","marks":[{"type":"strong"}],"text":"彈性伸縮"},{"type":"text","text":"，輕鬆應對峯值壓力"}]}]},{"type":"listitem","attrs":{"listStyle":null},"content":[{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"用戶只需根據函數的實際執行時間"},{"type":"text","marks":[{"type":"strong"}],"text":"按量付費"}]}]}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"因此，相比傳統開發模式，大大提高了開發和交付效率，是未來雲服務發展的大趨勢。自 2014 年始，在 AWS Lambda 之後，Google、IBM、Microsoft、阿里、騰訊、華爲等國內外雲廠商相繼推出雲函數計算平臺 FaaS。"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"heading","attrs":{"align":null,"level":3},"content":[{"type":"text","text":"快速創建 FaaS 應用"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"函數計算開發方式有很多種，比如：Fun 工具、函數計算 FC 平臺、Serverless VScode、雲開發平臺。本文藉助"},{"type":"text","marks":[{"type":"strong"}],"text":"阿里雲函數計算平臺"},{"type":"text","text":"(https:\/\/fc.console.aliyun.com\/fc\/overview\/cn-shanghai)，通過其提供的模版快速創建、部署一個 Web 應用，向大家更清楚地展示 FaaS 是什麼。"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"本文直接基於模版創建，用戶也可以選擇自己上傳應用代碼直接部署 Web 應用。"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"image","attrs":{"src":"https:\/\/static001.geekbang.org\/infoq\/36\/362b67e94d10e17c0fcb906ef2f0916d.png","alt":"Image","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}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"我們選擇有前後端交互、數據增刪改查等行爲的 "},{"type":"text","marks":[{"type":"strong"}],"text":"Todo List 應用"},{"type":"text","text":"，它是一個"},{"type":"text","marks":[{"type":"strong"}],"text":"前後端一體化"},{"type":"text","text":"（前後端代碼共屬一個項目中開發、調試、部署，高效且節省資源） FaaS 應用。"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"image","attrs":{"src":"https:\/\/static001.geekbang.org\/infoq\/f3\/f36b11250edf862d1de5a882cd713ad2.png","alt":"Image","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}},{"type":"heading","attrs":{"align":null,"level":3},"content":[{"type":"text","text":"服務\/函數"}]},{"type":"heading","attrs":{"align":null,"level":4},"content":[{"type":"text","text":"服務"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"一個應用可以拆分爲多個服務。從資源使用維度出發，一個服務可以由多個函數組成。先創建服務，再創建函數。"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"可以看到 TodoList 應用部署成功後創建好的服務，我們可以對該服務進行配置、刪除、查看指標等操作，還可以對其下的函數進行配置、刪除。"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"image","attrs":{"src":"https:\/\/static001.geekbang.org\/infoq\/bd\/bdea67ee47b9b1bfc961fd0041313fd7.png","alt":"Image","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}},{"type":"heading","attrs":{"align":null,"level":4},"content":[{"type":"text","text":"函數"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"函數是系統調度和運行的單位。函數必須從屬於服務，同一個服務下可以有多個函數，同一個服務下的所有函數共享相同的設置，例如服務授權、日誌配置，但彼此相互獨立，互不影響。"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"heading","attrs":{"align":null,"level":5},"content":[{"type":"text","text":"函數代碼"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"FaaS 對"},{"type":"text","marks":[{"type":"strong"}],"text":"多種語言"},{"type":"text","text":"都有良好的支持性，比如阿里雲支持 Node.js、Python、PHP、Java 等等，開發者可以使用自己熟悉的語言，根據平臺提供的函數接口形式編寫代碼。這也意味着，團隊協作時，大家可以利用多種語言混合開發複雜應用。"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"點擊代碼執行，可以看到這裏有一個在線編輯器，裏面就是模板生成的代碼，可以在此處進行運行、調試。該應用前端頁面用 React 實現，後端服務基於 Node 的 Express 框架。"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"image","attrs":{"src":"https:\/\/static001.geekbang.org\/infoq\/68\/68d719bef97752ed74d43ef48b60f116.png","alt":"Image","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}},{"type":"heading","attrs":{"align":null,"level":5},"content":[{"type":"text","text":"函數入口"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"codeinline","content":[{"type":"text","text":"template.yml"}]},{"type":"text","text":" 是我們的"},{"type":"text","marks":[{"type":"strong"}],"text":"函數信息配置文件"},{"type":"text","text":"，告訴雲廠商我們的代碼入口函數、觸發器類型等操作。"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"image","attrs":{"src":"https:\/\/static001.geekbang.org\/infoq\/bc\/bcc99142295dfae848af66c8cfcfc2c5.webp","alt":"Image","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}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"函數入口爲 "},{"type":"codeinline","content":[{"type":"text","text":"src\/index.handler"}]},{"type":"text","text":" ，即 "},{"type":"codeinline","content":[{"type":"text","text":"src\/index.js"}]},{"type":"text","text":" 服務端代碼文件中的 handler 方法，該文件代碼如下："}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"codeblock","attrs":{"lang":"javascript"},"content":[{"type":"text","text":"const { Server } = require('@webserverless\/fc-express')\nconst express = require('express');\nconst fs = require('fs');\nconst path = require('path');\nconst bodyParser = require('body-parser');\n\n\/\/ initial todo list\nlet todos = [\n  {\n    id: '123',\n    text: 'Go shopping',\n    isCompleted: false,\n  },\n  {\n    id: '213',\n    text: 'Clean room',\n    isCompleted: true,\n  },\n];\n\n\nconst staticBasePath = path.join('public', 'build');\n\nconst app = express();\n\n\/\/ index.html\napp.all(\"\/\", (req, resp) => {\n  resp.setHeader('Content-Type', 'text\/html');\n  resp.send(fs.readFileSync('.\/public\/build\/index.html', 'utf8'));\n});\n\n\/\/ 靜態資源文件：js、css、圖片\n\/\/ static js resources  \napp.all('\/*.js', (req, resp) => {\n  const filePath = path.join(staticBasePath, req.path);\n  resp.setHeader('Content-Type', 'text\/javascript');\n  resp.send(fs.readFileSync(filePath, 'utf8'));\n});\n\n\/\/ static css resources\napp.all('\/*.css', (req, resp) => {\n  const filePath = path.join(staticBasePath, req.path);\n  resp.setHeader('Content-Type', 'text\/css');\n  resp.send(fs.readFileSync(filePath, 'utf8'));\n});\n\n\/\/ static svg resources\napp.all('\/*.svg', (req, resp) => {\n  const filePath = path.join(staticBasePath, req.path);\n  resp.setHeader('Content-Type', 'image\/svg+xml');\n  resp.send(fs.readFileSync(filePath, 'utf8'));\n});\n\n\/\/ static png resources\napp.all('\/*.png', (req, resp) => {\n  const filePath = path.join(staticBasePath, req.path);\n  resp.setHeader('Content-Type', 'image\/png');\n  resp.send(fs.readFileSync(filePath, 'utf8'));\n});\n\napp.all('\/manifest.json', (req, resp) => {\n  const filePath = path.join(staticBasePath, req.path);\n  resp.setHeader('Content-Type', 'application\/json');\n  resp.send(fs.readFileSync(filePath, 'utf8'));\n});\n\n\/\/ 增刪改查對應的api接口\n\/\/ list api\napp.get('\/api\/listTodos', (req, resp) => {\n  resp.send(JSON.stringify(todos));\n});\n\n\/\/ create api\napp.get('\/api\/createTodo', (req, resp) => {\n  const { todo: todoStr } = req.query;\n  const todo = JSON.parse(todoStr);\n  todos.push({\n    id: todo.id,\n    text: todo.text,\n    isCompleted: todo.isCompleted,\n  });\n  resp.send(JSON.stringify(todos));\n});\n\n\/\/ update api\napp.get('\/api\/updateTodo', (req, resp) => {\n  const { todo: todoStr } = req.query;\n  const targetTodo = JSON.parse(todoStr);\n  const todo = todos.find((todo) => todo.id === targetTodo.id);\n  if (todo) {\n    todo.isCompleted = targetTodo.isCompleted;\n    todo.text = targetTodo.text;\n  }\n  resp.send(JSON.stringify(todos));\n});\n\n\/\/ remove api\napp.get('\/api\/removeTodo', (req, resp) => {\n  const { id } = req.query\n  \/\/ TODO: Implement methods to filter todos, filtering out item with the same id\n  \/\/ todos = todos.filter();\n  const todosIndex = todos.findIndex((todo) => todo.id === id);\n  if (todosIndex !== -1) {\n    todos.splice(todosIndex, 1);\n  } \n  resp.send(JSON.stringify(todos));\n});\n\nconst server = new Server(app);\n\n\/\/ 向外暴露了 http觸發器入口\n\/\/ http trigger entry\nmodule.exports.handler = function(req, res, context) {\n  server.httpProxy(req, res, context);\n};\n"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"可以看到，我們不需要自己起服務，FaaS 平臺會爲我們管理。這個文件，有兩個重要的部分："}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"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.函數入口 handler，也是 HTTP 觸發器入口，下文會詳細介紹"}]}]}]},{"type":"codeblock","attrs":{"lang":"typescript"},"content":[{"type":"text","text":"\/\/ http trigger entry\nmodule.exports.handler = function(req, res, context) {\n  server.httpProxy(req, res, context);\n};"}]},{"type":"bulletedlist","content":[{"type":"listitem","attrs":{"listStyle":null},"content":[{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"2.Web Service 和 API，通過路由調用相應的服務，比如請求路徑爲\"\/\"時，會返回 Web 應用的 Html 頁面；請求\"\/api\/*\"時，調用接口返回數據"}]}]}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"heading","attrs":{"align":null,"level":3},"content":[{"type":"text","text":"觸發器"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"前面說過，FaaS 是一種"},{"type":"text","marks":[{"type":"strong"}],"text":"事件驅動"},{"type":"text","text":"的計算模型，即函數的執行是由事件驅動的，沒有事件觸發，函數就不運行。與傳統開發模式不同，函數不需要自己啓動一個服務去監聽數據，而是通過綁定一個（或者多個）觸發器。"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"strong"}],"text":"觸發器"},{"type":"text","text":"就是觸發函數執行的方式，我們需要爲函數創建指定的觸發器。"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"FaaS 應用的觸發器有多種（不同雲廠商的觸發器會有所區別），但基本都支持 HTTP、對象存儲、定時任務、消息隊列等觸發器，其中 HTTP 觸發器是最常見的。"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"以阿里雲函數計算爲例，介紹幾個代表類型："}]},{"type":"heading","attrs":{"align":null,"level":4},"content":[{"type":"text","text":"觸發器類型"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"embedcomp","attrs":{"type":"table","data":{"content":"

名稱	描述
HTTP 觸發器	1.HTTP 觸發器通過發送 HTTP 請求觸發函數執行，主要適用於快速構建 Web 服務等場 2.HTTP 觸發器支持 HEAD、POST、PUT、GET 和 DELETE 方式觸發函數 3.可以通過綁定自定義域名爲 HTTP 函數映射不同的 HTTP 訪問路徑 4.開發人員可以快速使用 HTTP 觸發器搭建 Web Service和 API
OSS 觸發器（對象存儲）	1.OSS 事件能觸發相關函數執行，實現對 OSS 中的數據進行自定義處理
日誌服務觸發器	1.當日志服務定時獲取更新的數據時，通過日誌服務觸發器，觸發函數消費增量的日誌數據，並完成對數據的自定義加工
定時觸發器	1.在指定的時間點自動觸發函數執行
API 網關觸發器	1.API 網關作爲事件源，當有請求到達後端服務設置爲函數計算的 API 網關時，API 網關會觸發函數的執行。函數計算會將執行結果返回給 API 網關 2.與 HTTP 觸發器類似，可應用於搭建 Web 應用。相較於 HTTP 觸發器，您可以使用 API 網關進行 IP 白名單或黑名單設置等高級操作"}}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"開發者在調試時，如果不配置觸發器，也可以使用控制檯、命令行工具 或者 SDK 等方式直接調用函數執行。"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"我們點開 TodoList 的觸發器，可以看到創建的 "},{"type":"text","marks":[{"type":"strong"}],"text":"HTTP 觸發器"},{"type":"text","text":"，WEB 用戶通過 HTTP 請求即可觸發函數的執行。"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"image","attrs":{"src":"https:\/\/static001.geekbang.org\/infoq\/07\/079a2c3a759a99203e26734afddd7597.webp","alt":"Image","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}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"注意這裏的提示語：打開鏈接，會下載一個 Html 附件，這時我們打開，因爲找不到靜態資源文件，應用不能正常運行。"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"image","attrs":{"src":"https:\/\/static001.geekbang.org\/infoq\/8e\/8e15b415089a14b47b9f430b8a3d9db4.webp","alt":"Image","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}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"可以點擊"},{"type":"text","marks":[{"type":"strong"}],"text":"自定義域名"},{"type":"text","text":"去用平臺爲我們創建的"},{"type":"text","marks":[{"type":"strong"}],"text":"臨時域名"},{"type":"text","text":"打開："}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"image","attrs":{"src":"https:\/\/static001.geekbang.org\/infoq\/9f\/9fd0d0f2e8423edc4ae241fb74a65cbe.png","alt":"Image","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}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"可以看到，頁面和功能都正常了。我們查看、新增、更新、刪除，在控制檯裏可以看到發起的請求和返回結果"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"image","attrs":{"src":"https:\/\/static001.geekbang.org\/infoq\/1f\/1f003682f4f17b015e6db7357c73c3c3.png","alt":"Image","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}},{"type":"image","attrs":{"src":"https:\/\/static001.geekbang.org\/infoq\/da\/da09735ffcd524c5d2ff5e73d05c3382.webp","alt":"Image","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}},{"type":"image","attrs":{"src":"https:\/\/static001.geekbang.org\/infoq\/21\/21a106b9c614d1dc31034408bf61c36b.png","alt":"Image","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}},{"type":"heading","attrs":{"align":null,"level":4},"content":[{"type":"text","text":"HTTP 觸發器"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"該應用 "},{"type":"text","marks":[{"type":"strong"}],"text":"HTTP 觸發器的入口函數"},{"type":"text","text":"形式如下："}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"codeblock","attrs":{"lang":"javascript"},"content":[{"type":"text","text":"\/\/ http trigger entry\nmodule.exports.handler = function(req, res, context) {\n  server.httpProxy(req, res, context);\n};"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"strong"}],"text":"配置 HTTP 觸發器的函數可以通過 HTTP 請求被觸發執行。此時函數可以看做一個 Web Server，對 HTTP 請求進行處理，並將處理結果返回給調用端"},{"type":"text","text":"。"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"訪問 Html 頁面、請求靜態資源文件，以及請求接口，都是通過 HTTP 請求去觸發相應函數的執行。"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"可以在這裏進行調試："}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"image","attrs":{"src":"https:\/\/static001.geekbang.org\/infoq\/92\/922940f0dee33f941d7c8890a5b914f6.png","alt":"Image","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}},{"type":"heading","attrs":{"align":null,"level":3},"content":[{"type":"text","text":"FaaS 框架"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"目前市面上已經有一些較爲成熟的開源 FaaS 框架，比如 OpenFaaS、Funktion、Kubeless、Fission等等，本文向大家介紹阿里雲今年正式發佈的 "},{"type":"text","marks":[{"type":"strong"}],"text":"Midway FaaS框架"},{"type":"text","text":" (https:\/\/github.com\/midwayjs\/midway)，它是用於構建 Node.js 雲函數的 Serverless 框架，它提供了函數的本地"},{"type":"text","marks":[{"type":"strong"}],"text":"開發、調用、測試整個鏈路"},{"type":"text","text":"。它可以開發新的 Serveless 應用，也提供方案將傳統應用遷移至各雲廠商的雲函數。阿里內部已經使用一年多了。"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"我們可以運用腳手架 "},{"type":"codeinline","content":[{"type":"text","text":"@midwayjs\/faas-cli"}]},{"type":"text","text":" 提供的能力在"},{"type":"text","marks":[{"type":"strong"}],"text":"本地快速創建、調試、Mock、部署"},{"type":"text","text":"一個 FaaS 應用。Serverless 有一個很大的"},{"type":"text","marks":[{"type":"strong"}],"text":"弊端"},{"type":"text","text":"，就是"},{"type":"text","marks":[{"type":"strong"}],"text":"和雲服務商平臺強綁定"},{"type":"text","text":"，但是 Midway Serverles 是防平臺鎖定的，它能"},{"type":"text","marks":[{"type":"strong"}],"text":"一套代碼能夠運行在不同的平臺和運行時之上"},{"type":"text","text":"，Midaway Faas 的部署可以"},{"type":"text","marks":[{"type":"strong"}],"text":"跨雲廠商"},{"type":"text","text":"，默認部署到阿里雲 FC，我們也可以修改部署到其它平臺，如騰訊雲 SCF、AWS Lambda。"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"Midway FaaS 體系也與雲工作臺進行了結合，使用了和本地同樣的能力，這裏選擇登錄 "},{"type":"text","marks":[{"type":"strong"}],"text":"阿里雲開發平臺"},{"type":"text","text":" (https:\/\/workbench.aliyun.com\/application)，用示例庫模版再次創建一個 TodoList 應用進行演示，只不過這個是用 Midway FaaS 構建的。"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"image","attrs":{"src":"https:\/\/static001.geekbang.org\/infoq\/dc\/dc37299818000dbe150cb670ede10816.webp","alt":"Image","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}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"strong"}],"text":"代碼目錄結構"},{"type":"text","text":"可以簡單抽取爲："}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"codeblock","attrs":{"lang":null},"content":[{"type":"text","text":"|-- src\n|  |-- apis \/\/函數代碼\n|    |-- config \/\/針對不同環境創建配置文件\n|    |-- configuration.ts \/\/擴展能力配置\n|    |-- index.ts \/\/ 函數代碼入口文件，裏面包括多個函數\n|  |-- components \/\/ 前端組件\n|  |-- index.tsx \/\/ 前端頁面入口文件（該應用前端基於React，若是Vue，則是App.vue）\n|-- f.yml \/\/ 函數信息配置文件\n"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"f.yml 配置文件"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"codeblock","attrs":{"lang":null},"content":[{"type":"text","text":"service: serverless-hello-world\n\n\/\/ 服務提供商\nprovider:\n  name: aliyun\n  runtime: nodejs10 \/\/運行時環境及版本信息\n\n\/\/ 函數具體信息（包括函數入口、觸發器等等）\nfunctions:\n  render:\n    handler: render.handler \n    events:\n      - apigw:\n          path: \/*\n  list:\n    handler: todo.list \n    events:\n      - apigw:\n          path: \/api\/list\n  update:\n    handler: todo.update\n    events:\n      - apigw:\n          path: \/api\/update\n  remove:\n    handler: todo.remove\n    events:\n      - apigw:\n          path: \/api\/remove\n  add:\n    handler: todo.add\n    events:\n      - apigw:\n          path: \/api\/add\n          \n\/\/ 構建的配置信息\npackage:\n  include:\n    - build \/\/打包目錄\n  artifact: code.zip \/\/打包名稱\n"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"函數代碼中一個函數對應一個 API 接口："}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"image","attrs":{"src":"https:\/\/static001.geekbang.org\/infoq\/cc\/cc1d70fa4a36e07c5932fbfc37b3460e.png","alt":"Image","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}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"安裝依賴後，我們 "},{"type":"codeinline","content":[{"type":"text","text":"npm run 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