rinri
/
distributed-and-network-programming-course
1
0
Fork 0
Code Issues 0 Pull Requests 0 Releases 0 Wiki Activity
You can not select more than 25 topics Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
1 Commit
1 Branch
2.1 MiB
 
 
 
Branch: master
Branches Tags
${ item.name }
Create branch ${ searchTerm }
from 'master'
${ noResults }
distributed-and-network-pro.../lab6/Week 6.html

317 lines
42 KiB
Raw Permalink Blame History 

  1. <!DOCTYPE html>

  2. 

  3. <html lang="en">

  4. 

  5. <head>

  6.     <meta charset="utf-8">

  7.     <meta http-equiv="X-UA-Compatible" content="IE=edge">

  8.     <meta name="viewport" content="width=device-width, initial-scale=1.0, user-scalable=no">

  9.     <meta name="apple-mobile-web-app-capable" content="yes">

  10.     <meta name="apple-mobile-web-app-status-bar-style" content="black">

  11.     <meta name="mobile-web-app-capable" content="yes">

  12.     <title>

  13.         Week 6 - Distributed Consensus - HackMD

  14.     </title>

  15.     <link rel="icon" type="image/png" href="https://hackmd.io/favicon.png">

  16.     <link rel="apple-touch-icon" href="https://hackmd.io/apple-touch-icon.png">

  17. 

  18.     <link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/twitter-bootstrap/3.3.7/css/bootstrap.min.css" integrity="sha256-916EbMg70RQy9LHiGkXzG8hSg9EdNy97GazNG/aiY1w=" crossorigin="anonymous" />

  19.     <link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/font-awesome/4.7.0/css/font-awesome.min.css" integrity="sha256-eZrrJcwDc/3uDhsdt61sL2oOBY362qM3lon1gyExkL0=" crossorigin="anonymous" />

  20.     <link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/ionicons/2.0.1/css/ionicons.min.css" integrity="sha256-3iu9jgsy9TpTwXKb7bNQzqWekRX7pPK+2OLj3R922fo=" crossorigin="anonymous" />

  21.     <link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/octicons/3.5.0/octicons.min.css" integrity="sha256-QiWfLIsCT02Sdwkogf6YMiQlj4NE84MKkzEMkZnMGdg=" crossorigin="anonymous" />

  22.     <link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/prism/1.5.1/themes/prism.min.css" integrity="sha256-vtR0hSWRc3Tb26iuN2oZHt3KRUomwTufNIf5/4oeCyg=" crossorigin="anonymous" />

  23.     <link rel="stylesheet" href="https://cdn.jsdelivr.net/npm/@hackmd/emojify.js@2.1.0/dist/css/basic/emojify.min.css" integrity="sha256-UOrvMOsSDSrW6szVLe8ZDZezBxh5IoIfgTwdNDgTjiU=" crossorigin="anonymous" />

  24.     <style>

  25.         @import url(https://fonts.googleapis.com/css?family=Roboto:300,300i,400,400i,500,500i|Source+Code+Pro:300,400,500|Source+Sans+Pro:300,300i,400,400i,600,600i|Source+Serif+Pro&subset=latin-ext);.hljs{background:#fff;color:#333;display:block;overflow-x:auto;padding:.5em}.hljs-comment,.hljs-meta{color:#969896}.hljs-emphasis,.hljs-quote,.hljs-string,.hljs-strong,.hljs-template-variable,.hljs-variable{color:#df5000}.hljs-keyword,.hljs-selector-tag,.hljs-type{color:#a71d5d}.hljs-attribute,.hljs-bullet,.hljs-literal,.hljs-number,.hljs-symbol{color:#0086b3}.hljs-built_in,.hljs-builtin-name{color:#005cc5}.hljs-name,.hljs-section{color:#63a35c}.hljs-tag{color:#333}.hljs-attr,.hljs-selector-attr,.hljs-selector-class,.hljs-selector-id,.hljs-selector-pseudo,.hljs-title{color:#795da3}.hljs-addition{background-color:#eaffea;color:#55a532}.hljs-deletion{background-color:#ffecec;color:#bd2c00}.hljs-link{text-decoration:underline}.markdown-body{word-wrap:break-word;font-size:16px;line-height:1.5}.markdown-body:after,.markdown-body:before{content:"";display:table}.markdown-body:after{clear:both}.markdown-body>:first-child{margin-top:0!important}.markdown-body>:last-child{margin-bottom:0!important}.markdown-body a:not([href]){color:inherit;text-decoration:none}.markdown-body .absent{color:#c00}.markdown-body .anchor{float:left;line-height:1;margin-left:-20px;padding-right:4px}.markdown-body .anchor:focus{outline:none}.markdown-body blockquote,.markdown-body dl,.markdown-body ol,.markdown-body p,.markdown-body pre,.markdown-body table,.markdown-body ul{margin-bottom:16px;margin-top:0}.markdown-body hr{background-color:#e7e7e7;border:0;height:.25em;margin:24px 0;padding:0}.markdown-body blockquote{border-left:.25em solid #ddd;color:#777;font-size:16px;padding:0 1em}.markdown-body blockquote>:first-child{margin-top:0}.markdown-body blockquote>:last-child{margin-bottom:0}.markdown-body kbd,.popover kbd{background-color:#fcfcfc;border:1px solid;border-color:#ccc #ccc #bbb;border-radius:3px;box-shadow:inset 0 -1px 0 #bbb;color:#555;display:inline-block;font-size:11px;line-height:10px;padding:3px 5px;vertical-align:middle}.markdown-body .loweralpha{list-style-type:lower-alpha}.markdown-body h1,.markdown-body h2,.markdown-body h3,.markdown-body h4,.markdown-body h5,.markdown-body h6{font-weight:600;line-height:1.25;margin-bottom:16px;margin-top:24px}.markdown-body h1 .octicon-link,.markdown-body h2 .octicon-link,.markdown-body h3 .octicon-link,.markdown-body h4 .octicon-link,.markdown-body h5 .octicon-link,.markdown-body h6 .octicon-link{color:#000;vertical-align:middle;visibility:hidden}.markdown-body h1:hover .anchor,.markdown-body h2:hover .anchor,.markdown-body h3:hover .anchor,.markdown-body h4:hover .anchor,.markdown-body h5:hover .anchor,.markdown-body h6:hover .anchor{text-decoration:none}.markdown-body h1:hover .anchor .octicon-link,.markdown-body h2:hover .anchor .octicon-link,.markdown-body h3:hover .anchor .octicon-link,.markdown-body h4:hover .anchor .octicon-link,.markdown-body h5:hover .anchor .octicon-link,.markdown-body h6:hover .anchor .octicon-link{visibility:visible}.markdown-body h1 code,.markdown-body h1 tt,.markdown-body h2 code,.markdown-body h2 tt,.markdown-body h3 code,.markdown-body h3 tt,.markdown-body h4 code,.markdown-body h4 tt,.markdown-body h5 code,.markdown-body h5 tt,.markdown-body h6 code,.markdown-body h6 tt{font-size:inherit}.markdown-body h1{font-size:2em}.markdown-body h1,.markdown-body h2{border-bottom:1px solid #eee;padding-bottom:.3em}.markdown-body h2{font-size:1.5em}.markdown-body h3{font-size:1.25em}.markdown-body h4{font-size:1em}.markdown-body h5{font-size:.875em}.markdown-body h6{color:#777;font-size:.85em}.markdown-body ol,.markdown-body ul{padding-left:2em}.markdown-body ol.no-list,.markdown-body ul.no-list{list-style-type:none;padding:0}.markdown-body ol ol,.markdown-body ol ul,.markdown-body ul ol,.markdown-body ul ul{margin-bottom:0;margin-top:0}.markdown-body li>p{margin-top:16px}.markdown-body li+li{padding-top:.25em}.markdown-body dl{padding:0}.markdown-body dl dt{font-size:1em;font-style:italic;font-weight:700;margin-top:16px;padding:0}.markdown-body dl dd{margin-bottom:16px;padding:0 16px}.markdown-body table{display:block;overflow:auto;width:100%;word-break:normal;word-break:keep-all}.markdown-body table th{font-weight:700}.markdown-body table td,.markdown-body table th{border:1px solid #ddd;padding:6px 13px}.markdown-body table tr{background-color:#fff;border-top:1px solid #ccc}.markdown-body table tr:nth-child(2n){background-color:#f8f8f8}.markdown-body img{background-color:#fff;box-sizing:initial;max-width:100%}.markdown-body img[align=right]{padding-left:20px}.markdown-body img[align=left]{padding-right:20px}.markdown-body .emoji{background-color:initial;max-width:none;vertical-align:text-top}.markdown-body span.frame{display:block;overflow:hidden}.markdown-body span.frame>span{border:1px solid #ddd;display:block;float:left;margin:13px 0 0;overflow:hidden;padding:7px;width:auto}.markdown-body span.frame span img{display:block;float:left}.markdown-body span.frame span span{clear:both;color:#333;display:block;padding:5px 0 0}.markdown-body span.align-center{clear:both;display:block;overflow:hidden}.markdown-body span.align-center>span{display:block;margin:13px auto 0;overflow:hidden;text-align:center}.markdown-body span.align-center span img{margin:0 auto;text-align:center}.markdown-body span.align-right{clear:both;display:block;overflow:hidden}.markdown-body span.align-right>span{display:block;margin:13px 0 0;overflow:hidden;text-align:right}.markdown-body span.align-right span img{margin:0;text-align:right}.markdown-body span.float-left{display:block;float:left;margin-right:13px;overflow:hidden}.markdown-body span.float-left span{margin:13px 0 0}.markdown-body span.float-right{display:block;float:right;margin-left:13px;overflow:hidden}.markdown-body span.float-right>span{display:block;margin:13px auto 0;overflow:hidden;text-align:right}.markdown-body code,.markdown-body tt{background-color:#0000000a;border-radius:3px;font-size:85%;margin:0;padding:.2em 0}.markdown-body code:after,.markdown-body code:before,.markdown-body tt:after,.markdown-body tt:before{content:"\00a0";letter-spacing:-.2em}.markdown-body code br,.markdown-body tt br{display:none}.markdown-body del code{text-decoration:inherit}.markdown-body pre{word-wrap:normal}.markdown-body pre>code{background:#0000;border:0;font-size:100%;margin:0;padding:0;white-space:pre;word-break:normal}.markdown-body .highlight{margin-bottom:16px}.markdown-body .highlight pre{margin-bottom:0;word-break:normal}.markdown-body .highlight pre,.markdown-body pre{background-color:#f7f7f7;border-radius:3px;font-size:85%;line-height:1.45;overflow:auto;padding:16px}.markdown-body pre code,.markdown-body pre tt{word-wrap:normal;background-color:initial;border:0;display:inline;line-height:inherit;margin:0;max-width:auto;overflow:visible;padding:0}.markdown-body pre code:after,.markdown-body pre code:before,.markdown-body pre tt:after,.markdown-body pre tt:before{content:normal}.markdown-body .csv-data td,.markdown-body .csv-data th{font-size:12px;line-height:1;overflow:hidden;padding:5px;text-align:left;white-space:nowrap}.markdown-body .csv-data .blob-line-num{background:#fff;border:0;padding:10px 8px 9px;text-align:right}.markdown-body .csv-data tr{border-top:0}.markdown-body .csv-data th{background:#f8f8f8;border-top:0;font-weight:700}.news .alert .markdown-body blockquote{border:0;padding:0 0 0 40px}.activity-tab .news .alert .commits,.activity-tab .news .markdown-body blockquote{padding-left:0}.task-list-item{list-style-type:none}.task-list-item label{font-weight:400}.task-list-item.enabled label{cursor:pointer}.task-list-item+.task-list-item{margin-top:3px}.task-list-item-checkbox{cursor:default!important;float:left;margin:.31em 0 .2em -1.3em!important;vertical-align:middle}.markdown-body{max-width:758px;overflow:visible!important;padding-bottom:40px;padding-top:40px;position:relative}.markdown-body.next-editor{overflow-x:hidden!important}.markdown-body .emoji{vertical-align:top}.markdown-body pre{border:inherit!important}.markdown-body code{color:inherit!important}.markdown-body pre code .wrapper{display:-moz-inline-flex;display:-ms-inline-flex;display:-o-inline-flex;display:inline-flex}.markdown-body pre code .gutter{float:left;overflow:hidden;-webkit-user-select:none;user-select:none}.markdown-body pre code .gutter.linenumber{border-right:3px solid #6ce26c!important;box-sizing:initial;color:#afafaf!important;cursor:default;display:inline-block;min-width:20px;padding:0 8px 0 0;position:relative;text-align:right;z-index:4}.markdown-body pre code .gutter.linenumber>span:before{content:attr(data-linenumber)}.markdown-body pre code .code{float:left;margin:0 0 0 16px}.markdown-body .gist .line-numbers{border-bottom:none;border-left:none;border-top:none}.markdown-body .gist .line-data{border:none}.markdown-body .gist table{border-collapse:inherit!important;border-spacing:0}.markdown-body code[data-gist-id]{background:none;padding:0}.markdown-body code[data-gist-id]:after,.markdown-body code[data-gist-id]:before{content:""}.markdown-body code[data-gist-id] .blob-num{border:unset}.markdown-body code[data-gist-id] table{margin-bottom:unset;overflow:unset}.markdown-body code[data-gist-id] table tr{background:unset}.markdown-body[dir=rtl] pre{direction:ltr}.markdown-body[dir=rtl] code{direction:ltr;unicode-bidi:embed}.markdown-body .alert>p:last-child{margin-bottom:0}.markdown-body pre.abc,.markdown-body pre.flow-chart,.markdown-body pre.graphviz,.markdown-body pre.mermaid,.markdown-body pre.sequence-diagram,.markdown-body pre.vega{background-color:inherit;border-radius:0;overflow:visible;text-align:center;white-space:inherit}.markdown-body pre.abc>code,.markdown-body pre.flow-chart>code,.markdown-body pre.graphviz>code,.markdown-body pre.mermaid>code,.markdown-body pre.sequence-diagram>code,.markdown-body pre.vega>code{text-align:left}.markdown-body pre.abc>svg,.markdown-body pre.flow-chart>svg,.markdown-body pre.graphviz>svg,.markdown-body pre.mermaid>svg,.markdown-body pre.sequence-diagram>svg,.markdown-body pre.vega>svg{height:100%;max-width:100%}.markdown-body pre>code.wrap{word-wrap:break-word;white-space:pre-wrap;white-space:-moz-pre-wrap;white-space:-pre-wrap;white-space:-o-pre-wrap}.markdown-body .alert>p:last-child,.markdown-body .alert>ul:last-child{margin-bottom:0}.markdown-body summary{display:list-item}.markdown-body summary:focus{outline:none}.markdown-body details summary{cursor:pointer}.markdown-body details:not([open])>:not(summary){display:none}.markdown-body figure{margin:1em 40px}.markdown-body .mark,.markdown-body mark{background-color:#fff1a7}.vimeo,.youtube{background-color:#000;background-position:50%;background-repeat:no-repeat;background-size:contain;cursor:pointer;display:table;overflow:hidden;text-align:center}.vimeo,.youtube{position:relative;width:100%}.youtube{padding-bottom:56.25%}.vimeo img{object-fit:contain;width:100%;z-index:0}.youtube img{object-fit:cover;z-index:0}.vimeo iframe,.youtube iframe,.youtube img{height:100%;left:0;position:absolute;top:0;width:100%}.vimeo iframe,.youtube iframe{vertical-align:middle;z-index:1}.vimeo .icon,.youtube .icon{color:#fff;height:auto;left:50%;opacity:.3;position:absolute;top:50%;transform:translate(-50%,-50%);transition:opacity .2s;width:auto;z-index:0}.vimeo:hover .icon,.youtube:hover .icon{opacity:.6;transition:opacity .2s}.slideshare .inner,.speakerdeck .inner{position:relative;width:100%}.slideshare .inner iframe,.speakerdeck .inner iframe{bottom:0;height:100%;left:0;position:absolute;right:0;top:0;width:100%}.figma{display:table;padding-bottom:56.25%;position:relative;width:100%}.figma iframe{border:1px solid #eee;bottom:0;height:100%;left:0;position:absolute;right:0;top:0;width:100%}.markmap-container{height:300px}.markmap-container>svg{height:100%;width:100%}.MJX_Assistive_MathML{display:none}#MathJax_Message{z-index:1000!important}.ui-infobar{color:#777;margin:25px auto -25px;max-width:760px;position:relative;z-index:2}.toc .invisable-node{list-style-type:none}.ui-toc{bottom:20px;position:fixed;z-index:998}.ui-toc.both-mode{margin-left:8px}.ui-toc.both-mode .ui-toc-label{border-bottom-left-radius:0;border-top-left-radius:0;height:40px;padding:10px 4px}.ui-toc-label{background-color:#e6e6e6;border:none;color:#868686;transition:opacity .2s}.ui-toc .open .ui-toc-label{color:#fff;opacity:1;transition:opacity .2s}.ui-toc-label:focus{background-color:#ccc;color:#000;opacity:.3}.ui-toc-label:hover{background-color:#ccc;opacity:1;transition:opacity .2s}.ui-toc-dropdown{margin-bottom:20px;margin-top:20px;max-height:70vh;max-width:45vw;overflow:auto;padding-left:10px;padding-right:10px;text-align:inherit;width:25vw}.ui-toc-dropdown>.toc{max-height:calc(70vh - 100px);overflow:auto}.ui-toc-dropdown[dir=rtl] .nav{letter-spacing:.0029em;padding-right:0}.ui-toc-dropdown a{overflow:hidden;text-overflow:ellipsis;white-space:pre}.ui-toc-dropdown .nav>li>a{color:#767676;display:block;font-size:13px;font-weight:500;padding:4px 20px}.ui-toc-dropdown .nav>li:first-child:last-child>ul,.ui-toc-dropdown .toc.expand ul{display:block}.ui-toc-dropdown .nav>li>a:focus,.ui-toc-dropdown .nav>li>a:hover{background-color:initial;border-left:1px solid #000;color:#000;padding-left:19px;text-decoration:none}.ui-toc-dropdown[dir=rtl] .nav>li>a:focus,.ui-toc-dropdown[dir=rtl] .nav>li>a:hover{border-left:none;border-right:1px solid #000;padding-right:19px}.ui-toc-dropdown .nav>.active:focus>a,.ui-toc-dropdown .nav>.active:hover>a,.ui-toc-dropdown .nav>.active>a{background-color:initial;border-left:2px solid #000;color:#000;font-weight:700;padding-left:18px}.ui-toc-dropdown[dir=rtl] .nav>.active:focus>a,.ui-toc-dropdown[dir=rtl] .nav>.active:hover>a,.ui-toc-dropdown[dir=rtl] .nav>.active>a{border-left:none;border-right:2px solid #000;padding-right:18px}.ui-toc-dropdown .nav .nav{display:none;padding-bottom:10px}.ui-toc-dropdown .nav>.active>ul{display:block}.ui-toc-dropdown .nav .nav>li>a{font-size:12px;font-weight:400;padding-bottom:1px;padding-left:30px;padding-top:1px}.ui-toc-dropdown[dir=rtl] .nav .nav>li>a{padding-right:30px}.ui-toc-dropdown .nav .nav>li>ul>li>a{font-size:12px;font-weight:400;padding-bottom:1px;padding-left:40px;padding-top:1px}.ui-toc-dropdown[dir=rtl] .nav .nav>li>ul>li>a{padding-right:40px}.ui-toc-dropdown .nav .nav>li>a:focus,.ui-toc-dropdown .nav .nav>li>a:hover{padding-left:29px}.ui-toc-dropdown[dir=rtl] .nav .nav>li>a:focus,.ui-toc-dropdown[dir=rtl] .nav .nav>li>a:hover{padding-right:29px}.ui-toc-dropdown .nav .nav>li>ul>li>a:focus,.ui-toc-dropdown .nav .nav>li>ul>li>a:hover{padding-left:39px}.ui-toc-dropdown[dir=rtl] .nav .nav>li>ul>li>a:focus,.ui-toc-dropdown[dir=rtl] .nav .nav>li>ul>li>a:hover{padding-right:39px}.ui-toc-dropdown .nav .nav>.active:focus>a,.ui-toc-dropdown .nav .nav>.active:hover>a,.ui-toc-dropdown .nav .nav>.active>a{font-weight:500;padding-left:28px}.ui-toc-dropdown[dir=rtl] .nav .nav>.active:focus>a,.ui-toc-dropdown[dir=rtl] .nav .nav>.active:hover>a,.ui-toc-dropdown[dir=rtl] .nav .nav>.active>a{padding-right:28px}.ui-toc-dropdown .nav .nav>.active>.nav>.active:focus>a,.ui-toc-dropdown .nav .nav>.active>.nav>.active:hover>a,.ui-toc-dropdown .nav .nav>.active>.nav>.active>a{font-weight:500;padding-left:38px}.ui-toc-dropdown[dir=rtl] .nav .nav>.active>.nav>.active:focus>a,.ui-toc-dropdown[dir=rtl] .nav .nav>.active>.nav>.active:hover>a,.ui-toc-dropdown[dir=rtl] .nav .nav>.active>.nav>.active>a{padding-right:38px}.markdown-body{font-family:-apple-system,BlinkMacSystemFont,Segoe UI,Helvetica Neue,Helvetica,Roboto,Arial,sans-serif,Apple Color Emoji,Segoe UI Emoji,Segoe UI Symbol}html[lang^=ja] .markdown-body{font-family:-apple-system,BlinkMacSystemFont,Segoe UI,Helvetica Neue,Helvetica,Roboto,Arial,Hiragino Kaku Gothic Pro,ヒラギノ角ゴ Pro W3,Osaka,Meiryo,メイリオ,MS Gothic,ＭＳ ゴシック,sans-serif,Apple Color Emoji,Segoe UI Emoji,Segoe UI Symbol}html[lang=zh-tw] .markdown-body{font-family:-apple-system,BlinkMacSystemFont,Segoe UI,Helvetica Neue,Helvetica,Roboto,Arial,PingFang TC,Microsoft JhengHei,微軟正黑,sans-serif,Apple Color Emoji,Segoe UI Emoji,Segoe UI Symbol}html[lang=zh-cn] .markdown-body{font-family:-apple-system,BlinkMacSystemFont,Segoe UI,Helvetica Neue,Helvetica,Roboto,Arial,PingFang SC,Microsoft YaHei,微软雅黑,sans-serif,Apple Color Emoji,Segoe UI Emoji,Segoe UI Symbol}html .markdown-body[lang^=ja]{font-family:-apple-system,BlinkMacSystemFont,Segoe UI,Helvetica Neue,Helvetica,Roboto,Arial,Hiragino Kaku Gothic Pro,ヒラギノ角ゴ Pro W3,Osaka,Meiryo,メイリオ,MS Gothic,ＭＳ ゴシック,sans-serif,Apple Color Emoji,Segoe UI Emoji,Segoe UI Symbol}html .markdown-body[lang=zh-tw]{font-family:-apple-system,BlinkMacSystemFont,Segoe UI,Helvetica Neue,Helvetica,Roboto,Arial,PingFang TC,Microsoft JhengHei,微軟正黑,sans-serif,Apple Color Emoji,Segoe UI Emoji,Segoe UI Symbol}html .markdown-body[lang=zh-cn]{font-family:-apple-system,BlinkMacSystemFont,Segoe UI,Helvetica Neue,Helvetica,Roboto,Arial,PingFang SC,Microsoft YaHei,微软雅黑,sans-serif,Apple Color Emoji,Segoe UI Emoji,Segoe UI Symbol}html[lang^=ja] .ui-toc-dropdown{font-family:Source Sans Pro,Helvetica,Arial,Meiryo UI,MS PGothic,ＭＳ Ｐゴシック,sans-serif}html[lang=zh-tw] .ui-toc-dropdown{font-family:Source Sans Pro,Helvetica,Arial,Microsoft JhengHei UI,微軟正黑UI,sans-serif}html[lang=zh-cn] .ui-toc-dropdown{font-family:Source Sans Pro,Helvetica,Arial,Microsoft YaHei UI,微软雅黑UI,sans-serif}html .ui-toc-dropdown[lang^=ja]{font-family:Source Sans Pro,Helvetica,Arial,Meiryo UI,MS PGothic,ＭＳ Ｐゴシック,sans-serif}html .ui-toc-dropdown[lang=zh-tw]{font-family:Source Sans Pro,Helvetica,Arial,Microsoft JhengHei UI,微軟正黑UI,sans-serif}html .ui-toc-dropdown[lang=zh-cn]{font-family:Source Sans Pro,Helvetica,Arial,Microsoft YaHei UI,微软雅黑UI,sans-serif}.ui-affix-toc{max-height:70vh;max-width:15vw;overflow:auto;position:fixed;top:0}.back-to-top,.expand-toggle,.go-to-bottom{color:#999;display:block;font-size:12px;font-weight:500;margin-left:10px;margin-top:10px;padding:4px 10px}.back-to-top:focus,.back-to-top:hover,.expand-toggle:focus,.expand-toggle:hover,.go-to-bottom:focus,.go-to-bottom:hover{color:#563d7c;text-decoration:none}.back-to-top,.go-to-bottom{margin-top:0}.ui-user-icon{background-position:50%;background-repeat:no-repeat;background-size:cover;border-radius:50%;display:block;height:20px;margin-bottom:2px;margin-right:5px;margin-top:2px;width:20px}.ui-user-icon.small{display:inline-block;height:18px;margin:0 0 .2em;vertical-align:middle;width:18px}.ui-infobar>small>span{line-height:22px}.ui-infobar>small .dropdown{display:inline-block}.ui-infobar>small .dropdown a:focus,.ui-infobar>small .dropdown a:hover{text-decoration:none}.ui-more-info{color:#888;cursor:pointer;vertical-align:middle}.ui-more-info .fa{font-size:16px}.ui-connectedGithub,.ui-published-note{color:#888}.ui-connectedGithub{line-height:23px;white-space:nowrap}.ui-connectedGithub a.file-path{color:#888;padding-left:22px;text-decoration:none}.ui-connectedGithub a.file-path:active,.ui-connectedGithub a.file-path:hover{color:#888;text-decoration:underline}.ui-connectedGithub .fa{font-size:20px}.ui-published-note .fa{font-size:20px;vertical-align:top}.unselectable{-webkit-user-select:none;-o-user-select:none;user-select:none}.selectable{-webkit-user-select:text;-o-user-select:text;user-select:text}.inline-spoiler-section{cursor:pointer}.inline-spoiler-section .spoiler-text{background-color:#333;border-radius:2px}.inline-spoiler-section .spoiler-text>*{opacity:0}.inline-spoiler-section .spoiler-img{filter:blur(10px)}.inline-spoiler-section.raw{background-color:#333;border-radius:2px}.inline-spoiler-section.raw>*{opacity:0}.inline-spoiler-section.unveil{cursor:auto}.inline-spoiler-section.unveil .spoiler-text{background-color:#3333331a}.inline-spoiler-section.unveil .spoiler-text>*{opacity:1}.inline-spoiler-section.unveil .spoiler-img{filter:none}@media print{blockquote,div,img,pre,table{page-break-inside:avoid!important}a[href]:after{font-size:12px!important}}.markdown-body.slides{color:#222;position:relative;z-index:1}.markdown-body.slides:before{background-color:currentColor;bottom:0;box-shadow:0 0 0 50vw;content:"";display:block;left:0;position:absolute;right:0;top:0;z-index:-1}.markdown-body.slides section[data-markdown]{background-color:#fff;margin-bottom:1.5em;position:relative;text-align:center}.markdown-body.slides section[data-markdown] code{text-align:left}.markdown-body.slides section[data-markdown]:before{content:"";display:block;padding-bottom:56.23%}.markdown-body.slides section[data-markdown]>div:first-child{left:1em;max-height:100%;overflow:hidden;position:absolute;right:1em;top:50%;transform:translateY(-50%)}.markdown-body.slides section[data-markdown]>ul{display:inline-block}.markdown-body.slides>section>section+section:after{border:3px solid #777;content:"";height:1.5em;position:absolute;right:1em;top:-1.5em}.site-ui-font{font-family:Source Sans Pro,Helvetica,Arial,sans-serif}html[lang^=ja] .site-ui-font{font-family:Source Sans Pro,Helvetica,Arial,Hiragino Kaku Gothic Pro,ヒラギノ角ゴ Pro W3,Osaka,Meiryo,メイリオ,MS Gothic,ＭＳ ゴシック,sans-serif}html[lang=zh-tw] .site-ui-font{font-family:Source Sans Pro,Helvetica,Arial,PingFang TC,Microsoft JhengHei,微軟正黑,sans-serif}html[lang=zh-cn] .site-ui-font{font-family:Source Sans Pro,Helvetica,Arial,PingFang SC,Microsoft YaHei,微软雅黑,sans-serif}body{font-smoothing:subpixel-antialiased!important;-webkit-font-smoothing:subpixel-antialiased!important;-moz-osx-font-smoothing:auto!important;-webkit-overflow-scrolling:touch;font-family:Source Sans Pro,Helvetica,Arial,sans-serif;letter-spacing:.025em}html[lang^=ja] body{font-family:Source Sans Pro,Helvetica,Arial,Hiragino Kaku Gothic Pro,ヒラギノ角ゴ Pro W3,Osaka,Meiryo,メイリオ,MS Gothic,ＭＳ ゴシック,sans-serif}html[lang=zh-tw] body{font-family:Source Sans Pro,Helvetica,Arial,PingFang TC,Microsoft JhengHei,微軟正黑,sans-serif}html[lang=zh-cn] body{font-family:Source Sans Pro,Helvetica,Arial,PingFang SC,Microsoft YaHei,微软雅黑,sans-serif}abbr[title]{border-bottom:none;text-decoration:underline;-webkit-text-decoration:underline dotted;text-decoration:underline dotted}abbr[data-original-title],abbr[title]{cursor:help}body.modal-open{overflow-y:auto;padding-right:0!important}svg{text-shadow:none}

  26.     </style>

  27.     <!-- HTML5 shim and Respond.js for IE8 support of HTML5 elements and media queries -->

  28.     <!-- WARNING: Respond.js doesn't work if you view the page via file:// -->

  29.     <!--[if lt IE 9]>

  30.     	<script src="https://cdnjs.cloudflare.com/ajax/libs/html5shiv/3.7.3/html5shiv.min.js" integrity="sha256-3Jy/GbSLrg0o9y5Z5n1uw0qxZECH7C6OQpVBgNFYa0g=" crossorigin="anonymous"></script>

  31.     	<script src="https://cdnjs.cloudflare.com/ajax/libs/respond.js/1.4.2/respond.min.js" integrity="sha256-g6iAfvZp+nDQ2TdTR/VVKJf3bGro4ub5fvWSWVRi2NE=" crossorigin="anonymous"></script>

  32. 		<script src="https://cdnjs.cloudflare.com/ajax/libs/es5-shim/4.5.9/es5-shim.min.js" integrity="sha256-8E4Is26QH0bD52WoQpcB+R/tcWQtpzlCojrybUd7Mxo=" crossorigin="anonymous"></script>

  33.     <![endif]-->

  34. </head>

  35. 

  36. <body>

  37.     <div id="doc" class="markdown-body container-fluid comment-inner comment-enabled" data-hard-breaks="true"><h1 id="Week-6---Distributed-Consensus" data-id="Week-6---Distributed-Consensus"><a class="anchor hidden-xs" href="#Week-6---Distributed-Consensus" title="Week-6---Distributed-Consensus"><span class="octicon octicon-link"></span></a><span>Week 6 - Distributed Consensus</span></h1><blockquote>

  38. <p><span>Distributed Systems and Network Programming - Spring 2023</span></p>

  39. </blockquote><h2 id="Overview" data-id="Overview"><a class="anchor hidden-xs" href="#Overview" title="Overview"><span class="octicon octicon-link"></span></a><span>Overview</span></h2><p><span>Your task for this lab is to use </span><a href="https://en.wikipedia.org/wiki/Raft_(algorithm)" target="_blank" rel="noopener"><span>RAFT</span></a><span> algorithm to maintain consensus between 3 nodes in a P2P system. All nodes in the cluster need to maintain a consistent replicated log (list of strings).</span></p><h2 id="Brief-Algorithm-Description" data-id="Brief-Algorithm-Description"><a class="anchor hidden-xs" href="#Brief-Algorithm-Description" title="Brief-Algorithm-Description"><span class="octicon octicon-link"></span></a><span>Brief Algorithm Description</span></h2><p><span>RAFT works in two phases: </span><strong><span>leader election</span></strong><span> and </span><strong><span>log replication</span></strong><span>.</span></p><ul>

  40. <li><span>Check </span><a href="https://thesecretlivesofdata.com/raft" target="_blank" rel="noopener"><span>this</span></a><span> visualization for a better understanding.</span></li>

  41. </ul><h3 id="Leader-Election" data-id="Leader-Election"><a class="anchor hidden-xs" href="#Leader-Election" title="Leader-Election"><span class="octicon octicon-link"></span></a><span>Leader Election</span></h3><ul>

  42. <li><span>In this phase, nodes must select a leader to be the single trusted source of information.</span></li>

  43. <li><span>Leader election algorithm should be fault tolerant.</span>

  44. <ul>

  45. <li><span>The system should stay operational as nodes go online or offline.</span></li>

  46. <li><span>If a leader goes offline, a new leader should be elected.</span></li>

  47. </ul>

  48. </li>

  49. <li><span>This is implemented using node states, election and heartbeat timers, and election term.</span></li>

  50. </ul><h3 id="Log-Replication" data-id="Log-Replication"><a class="anchor hidden-xs" href="#Log-Replication" title="Log-Replication"><span class="octicon octicon-link"></span></a><span>Log Replication</span></h3><ul>

  51. <li><span>In this phase, a client sends updates (log entries) to the leader.</span></li>

  52. <li><span>The leader should propagate this information to online followers.</span></li>

  53. <li><span>All online nodes in the cluster should maintain the same log.</span></li>

  54. </ul><h2 id="Task" data-id="Task"><a class="anchor hidden-xs" href="#Task" title="Task"><span class="octicon octicon-link"></span></a><span>Task</span></h2><ul>

  55. <li>

  56. <p><span>Implement a RAFT node to communicate with the given client.</span></p>

  57. </li>

  58. <li>

  59. <p><span>You may use the given boilerplate code or write your own.</span></p>

  60. <ul>

  61. <li><span>Logging that shows all major events in the cluster is required for grading.</span></li>

  62. <li><span>Check the output below for reference, similar logging is required.</span></li>

  63. </ul>

  64. </li>

  65. <li>

  66. <p><span>Use larger timeouts for easier inspection of the output</span></p>

  67. <ul>

  68. <li><code>ELECTION_TIMEOUT</code><span>: chosen uniformly between 6 and 8 seconds.</span></li>

  69. <li><code>HEARTBEAT_INTERVAL</code><span>: 5 seconds.</span></li>

  70. </ul>

  71. </li>

  72. </ul><h2 id="Example-Run" data-id="Example-Run"><a class="anchor hidden-xs" href="#Example-Run" title="Example-Run"><span class="octicon octicon-link"></span></a><span>Example Run</span></h2><h3 id="Input" data-id="Input"><a class="anchor hidden-xs" href="#Input" title="Input"><span class="octicon octicon-link"></span></a><span>Input</span></h3><ul>

  73. <li>

  74. <p><span>We have prepared an example cluster of 3 nodes (numbered from 1 to 3) and the required docker files to run all such nodes in one network, nodes are reachable from each other by their hostname (e.g., </span><code>http://node_1:1234</code><span>)</span></p>

  75. </li>

  76. <li>

  77. <p><span>An example client is also provided (</span><code>client.py</code><span>). The client runs in the same network with nodes and contacts the leader node (after leader election is done) to insert some data into the log.</span></p>

  78. </li>

  79. <li>

  80. <p><span>To run the example, execute the following command in the project directory</span></p>

  81. <pre><code class="bash hljs">docker-compose build --no-cache &amp;&amp; docker-compose up

  82. </code></pre>

  83. </li>

  84. </ul><h3 id="Output" data-id="Output"><a class="anchor hidden-xs" href="#Output" title="Output"><span class="octicon octicon-link"></span></a><span>Output</span></h3><h4 id="Typical-Run" data-id="Typical-Run"><a class="anchor hidden-xs" href="#Typical-Run" title="Typical-Run"><span class="octicon octicon-link"></span></a><span>Typical Run</span></h4><ul>

  85. <li><span>No interruptions or split-votes occur. Log replication happens normally.</span></li>

  86. </ul><p><img src="https://i.imgur.com/vHSO5KT.png" alt="typical_run" loading="lazy"></p><h4 id="Split-vote-case" data-id="Split-vote-case"><a class="anchor hidden-xs" href="#Split-vote-case" title="Split-vote-case"><span class="octicon octicon-link"></span></a><span>Split-vote case</span></h4><ul>

  87. <li><span>Nodes 1 and 3 hold elections simultaneously</span></li>

  88. <li><span>Only one of them should win and the elections should stop occurring</span></li>

  89. </ul><p><img src="https://i.imgur.com/rnU4S2i.png" alt="split_vote" loading="lazy"></p><h4 id="Dead-leader" data-id="Dead-leader"><a class="anchor hidden-xs" href="#Dead-leader" title="Dead-leader"><span class="octicon octicon-link"></span></a><span>Dead leader</span></h4><ul>

  90. <li><span>Ran </span><code>docker container stop node_3</code><span> to stop the leader</span></li>

  91. <li><span>Election happened and </span><code>node_1</code><span> became the new leader</span></li>

  92. <li><span>Ran </span><code>docker container start node_3</code><span> to revive the dead leader</span></li>

  93. <li><span>Old leader is now a follower and receives heartbeats from </span><code>node_1</code></li>

  94. </ul><p><img src="https://i.imgur.com/z7lTJ2U.png" alt="img" loading="lazy"></p><h4 id="Dead-follower" data-id="Dead-follower"><a class="anchor hidden-xs" href="#Dead-follower" title="Dead-follower"><span class="octicon octicon-link"></span></a><span>Dead follower</span></h4><ul>

  95. <li><span>Same as the above case, but stopping a follower (</span><code>node_1</code><span>) instead of the leader.</span></li>

  96. <li><span>Election may happen, but leader should not change.</span></li>

  97. <li><span>When the follower rejoins, everything goes back to normal.</span></li>

  98. </ul><p><img src="https://i.imgur.com/tyBdpwU.png" alt="dead_follower" loading="lazy"></p><h2 id="Checklist" data-id="Checklist"><a class="anchor hidden-xs" href="#Checklist" title="Checklist"><span class="octicon octicon-link"></span></a><span>Checklist</span></h2><ul class="contains-task-list">

  99. <li class="task-list-item enabled"><input class="task-list-item-checkbox" type="checkbox" disabled="disabled"><span> A single submitted file (</span><code>node_NameSurname.py</code><span>)</span></li>

  100. <li class="task-list-item enabled"><input class="task-list-item-checkbox" type="checkbox" disabled="disabled"><span> The code is readable and does not use any external dependencies</span></li>

  101. <li class="task-list-item enabled"><input class="task-list-item-checkbox" type="checkbox" disabled="disabled"><span> Logging shows all major system events in detail (check example run above)</span></li>

  102. <li class="task-list-item enabled"><input class="task-list-item-checkbox" type="checkbox" disabled="disabled"><span> Leader election and log replication are correctly implemented (depends on the above point)</span></li>

  103. <li class="task-list-item enabled"><input class="task-list-item-checkbox" type="checkbox" disabled="disabled"><span> The system is resilient to random testing (nodes may go online or offline any time)</span></li>

  104. <li class="task-list-item enabled"><input class="task-list-item-checkbox" type="checkbox" disabled="disabled"><span> The source code is the author’s original work. Both parties will be penalized for detected plagiarism</span></li>

  105. </ul><h2 id="Additional-Notes" data-id="Additional-Notes"><a class="anchor hidden-xs" href="#Additional-Notes" title="Additional-Notes"><span class="octicon octicon-link"></span></a><span>Additional Notes</span></h2><ul>

  106. <li><span>Original RAFT paper and a list of popular implementations are available </span><a href="https://raft.github.io/" target="_blank" rel="noopener"><span>here</span></a></li>

  107. <li><span>The following simplifications were made to adjust the complexity of the task:</span>

  108. <ul>

  109. <li><span>The number of nodes in the cluster is fixed to 3.</span></li>

  110. <li><span>Nodes may go online or offline any time, except while logs are being propagated.</span></li>

  111. <li><span>A revived node does not need to re-obtain historical logs.</span></li>

  112. <li><span>Client logic is separated from node logic for easier testing.</span></li>

  113. <li><span>The network is assumed to be reliable and network partitioning will not happen.</span></li>

  114. </ul>

  115. </li>

  116. </ul></div>

  117.     <div class="ui-toc dropup unselectable hidden-print" style="display:none;">

  118.         <div class="pull-right dropdown">

  119.             <a id="tocLabel" class="ui-toc-label btn btn-default" data-toggle="dropdown" href="#" role="button" aria-haspopup="true" aria-expanded="false" title="Table of content">

  120.                 <i class="fa fa-bars"></i>

  121.             </a>

  122.             <ul id="ui-toc" class="ui-toc-dropdown dropdown-menu" aria-labelledby="tocLabel">

  123.                 <div class="toc"><ul class="nav">

  124. <li class=""><a href="#Week-6---Distributed-Consensus" title="Week 6 - Distributed Consensus">Week 6 - Distributed Consensus</a><ul class="nav">

  125. <li class=""><a href="#Overview" title="Overview">Overview</a></li>

  126. <li class=""><a href="#Brief-Algorithm-Description" title="Brief Algorithm Description">Brief Algorithm Description</a><ul class="nav">

  127. <li class=""><a href="#Leader-Election" title="Leader Election">Leader Election</a></li>

  128. <li class=""><a href="#Log-Replication" title="Log Replication">Log Replication</a></li>

  129. </ul>

  130. </li>

  131. <li class=""><a href="#Task" title="Task">Task</a></li>

  132. <li class=""><a href="#Example-Run" title="Example Run">Example Run</a><ul class="nav">

  133. <li class=""><a href="#Input" title="Input">Input</a></li>

  134. <li class=""><a href="#Output" title="Output">Output</a></li>

  135. </ul>

  136. </li>

  137. <li><a href="#Checklist" title="Checklist">Checklist</a></li>

  138. <li class=""><a href="#Additional-Notes" title="Additional Notes">Additional Notes</a></li>

  139. </ul>

  140. </li>

  141. </ul>

  142. </div><div class="toc-menu"><a class="expand-toggle" href="#">Expand all</a><a class="back-to-top" href="#">Back to top</a><a class="go-to-bottom" href="#">Go to bottom</a></div>

  143.             </ul>

  144.         </div>

  145.     </div>

  146.     <div id="ui-toc-affix" class="ui-affix-toc ui-toc-dropdown unselectable hidden-print" data-spy="affix" style="top:17px;display:none;" null null>

  147.         <div class="toc"><ul class="nav">

  148. <li class=""><a href="#Week-6---Distributed-Consensus" title="Week 6 - Distributed Consensus">Week 6 - Distributed Consensus</a><ul class="nav">

  149. <li class=""><a href="#Overview" title="Overview">Overview</a></li>

  150. <li class=""><a href="#Brief-Algorithm-Description" title="Brief Algorithm Description">Brief Algorithm Description</a><ul class="nav">

  151. <li class=""><a href="#Leader-Election" title="Leader Election">Leader Election</a></li>

  152. <li class=""><a href="#Log-Replication" title="Log Replication">Log Replication</a></li>

  153. </ul>

  154. </li>

  155. <li class=""><a href="#Task" title="Task">Task</a></li>

  156. <li class=""><a href="#Example-Run" title="Example Run">Example Run</a><ul class="nav">

  157. <li class=""><a href="#Input" title="Input">Input</a></li>

  158. <li class=""><a href="#Output" title="Output">Output</a></li>

  159. </ul>

  160. </li>

  161. <li><a href="#Checklist" title="Checklist">Checklist</a></li>

  162. <li class=""><a href="#Additional-Notes" title="Additional Notes">Additional Notes</a></li>

  163. </ul>

  164. </li>

  165. </ul>

  166. </div><div class="toc-menu"><a class="expand-toggle" href="#">Expand all</a><a class="back-to-top" href="#">Back to top</a><a class="go-to-bottom" href="#">Go to bottom</a></div>

  167.     </div>

  168.     <script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.1.1/jquery.min.js" integrity="sha256-hVVnYaiADRTO2PzUGmuLJr8BLUSjGIZsDYGmIJLv2b8=" crossorigin="anonymous"></script>

  169.     <script src="https://cdnjs.cloudflare.com/ajax/libs/twitter-bootstrap/3.3.7/js/bootstrap.min.js" integrity="sha256-U5ZEeKfGNOja007MMD3YBI0A3OSZOQbeG6z2f2Y0hu8=" crossorigin="anonymous" defer></script>

  170.     <script src="https://cdnjs.cloudflare.com/ajax/libs/gist-embed/2.6.0/gist-embed.min.js" integrity="sha256-KyF2D6xPIJUW5sUDSs93vWyZm+1RzIpKCexxElmxl8g=" crossorigin="anonymous" defer></script>

  171.     <script>

  172.         var markdown = $(".markdown-body");

  173.         //smooth all hash trigger scrolling

  174.         function smoothHashScroll() {

  175.             var hashElements = $("a[href^='#']").toArray();

  176.             for (var i = 0; i < hashElements.length; i++) {

  177.                 var element = hashElements[i];

  178.                 var $element = $(element);

  179.                 var hash = element.hash;

  180.                 if (hash) {

  181.                     $element.on('click', function (e) {

  182.                         // store hash

  183.                         var hash = this.hash;

  184.                         if ($(hash).length <= 0) return;

  185.                         // prevent default anchor click behavior

  186.                         e.preventDefault();

  187.                         // animate

  188.                         $('body, html').stop(true, true).animate({

  189.                             scrollTop: $(hash).offset().top

  190.                         }, 100, "linear", function () {

  191.                             // when done, add hash to url

  192.                             // (default click behaviour)

  193.                             window.location.hash = hash;

  194.                         });

  195.                     });

  196.                 }

  197.             }

  198.         }

  199. 

  200.         smoothHashScroll();

  201.         var toc = $('.ui-toc');

  202.         var tocAffix = $('.ui-affix-toc');

  203.         var tocDropdown = $('.ui-toc-dropdown');

  204.         //toc

  205.         tocDropdown.click(function (e) {

  206.             e.stopPropagation();

  207.         });

  208. 

  209.         var enoughForAffixToc = true;

  210. 

  211.         function generateScrollspy() {

  212.             $(document.body).scrollspy({

  213.                 target: ''

  214.             });

  215.             $(document.body).scrollspy('refresh');

  216.             if (enoughForAffixToc) {

  217.                 toc.hide();

  218.                 tocAffix.show();

  219.             } else {

  220.                 tocAffix.hide();

  221.                 toc.show();

  222.             }

  223.             $(document.body).scroll();

  224.         }

  225. 

  226.         function windowResize() {

  227.             //toc right

  228.             var paddingRight = parseFloat(markdown.css('padding-right'));

  229.             var right = ($(window).width() - (markdown.offset().left + markdown.outerWidth() - paddingRight));

  230.             toc.css('right', right + 'px');

  231.             //affix toc left

  232.             var newbool;

  233.             var rightMargin = (markdown.parent().outerWidth() - markdown.outerWidth()) / 2;

  234.             //for ipad or wider device

  235.             if (rightMargin >= 133) {

  236.                 newbool = true;

  237.                 var affixLeftMargin = (tocAffix.outerWidth() - tocAffix.width()) / 2;

  238.                 var left = markdown.offset().left + markdown.outerWidth() - affixLeftMargin;

  239.                 tocAffix.css('left', left + 'px');

  240.             } else {

  241.                 newbool = false;

  242.             }

  243.             if (newbool != enoughForAffixToc) {

  244.                 enoughForAffixToc = newbool;

  245.                 generateScrollspy();

  246.             }

  247.         }

  248.         $(window).resize(function () {

  249.             windowResize();

  250.         });

  251.         $(document).ready(function () {

  252.             windowResize();

  253.             generateScrollspy();

  254.         });

  255. 

  256.         //remove hash

  257.         function removeHash() {

  258.             window.location.hash = '';

  259.         }

  260. 

  261.         var backtotop = $('.back-to-top');

  262.         var gotobottom = $('.go-to-bottom');

  263. 

  264.         backtotop.click(function (e) {

  265.             e.preventDefault();

  266.             e.stopPropagation();

  267.             if (scrollToTop)

  268.                 scrollToTop();

  269.             removeHash();

  270.         });

  271.         gotobottom.click(function (e) {

  272.             e.preventDefault();

  273.             e.stopPropagation();

  274.             if (scrollToBottom)

  275.                 scrollToBottom();

  276.             removeHash();

  277.         });

  278. 

  279.         var toggle = $('.expand-toggle');

  280.         var tocExpand = false;

  281. 

  282.         checkExpandToggle();

  283.         toggle.click(function (e) {

  284.             e.preventDefault();

  285.             e.stopPropagation();

  286.             tocExpand = !tocExpand;

  287.             checkExpandToggle();

  288.         })

  289. 

  290.         function checkExpandToggle () {

  291.             var toc = $('.ui-toc-dropdown .toc');

  292.             var toggle = $('.expand-toggle');

  293.             if (!tocExpand) {

  294.                 toc.removeClass('expand');

  295.                 toggle.text('Expand all');

  296.             } else {

  297.                 toc.addClass('expand');

  298.                 toggle.text('Collapse all');

  299.             }

  300.         }

  301. 

  302.         function scrollToTop() {

  303.             $('body, html').stop(true, true).animate({

  304.                 scrollTop: 0

  305.             }, 100, "linear");

  306.         }

  307. 

  308.         function scrollToBottom() {

  309.             $('body, html').stop(true, true).animate({

  310.                 scrollTop: $(document.body)[0].scrollHeight

  311.             }, 100, "linear");

  312.         }

  313.     </script>

  314. </body>

  315. 

  316. </html>