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| author | Loïc Hoguin <[email protected]> | 2018-05-02 11:35:26 +0200 |
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| committer | Loïc Hoguin <[email protected]> | 2018-05-02 11:35:26 +0200 |
| commit | fec98300ec9af6c8b5f3120a60f217983c451076 (patch) | |
| tree | 9772977293124e8b9b5b253e44d8c2695cddfb44 /docs/en/cowboy/2.4/guide/erlang_web/index.html | |
| parent | bfd2b6e01cbb36b0be0b3c860f5baf8d5b49fe7a (diff) | |
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Cowboy 2.4.0
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diff --git a/docs/en/cowboy/2.4/guide/erlang_web/index.html b/docs/en/cowboy/2.4/guide/erlang_web/index.html new file mode 100644 index 00000000..845f3bf4 --- /dev/null +++ b/docs/en/cowboy/2.4/guide/erlang_web/index.html @@ -0,0 +1,354 @@ +<!DOCTYPE html> +<html lang="en"> + +<head> + <meta charset="utf-8"> + <meta name="viewport" content="width=device-width, initial-scale=1.0"> + <meta name="description" content=""> + <meta name="author" content="Loïc Hoguin based on a design from (Soft10) Pol Cámara"> + + <meta name="generator" content="Hugo 0.37.1" /> + + <title>Nine Nines: Erlang and the Web</title> + + <link href='https://fonts.googleapis.com/css?family=Open+Sans:400,700,400italic' rel='stylesheet' type='text/css'> + <link href="/css/99s.css?r=1" rel="stylesheet"> + + <link rel="shortcut icon" href="/img/ico/favicon.ico"> + <link rel="apple-touch-icon-precomposed" sizes="114x114" href="/img/ico/apple-touch-icon-114.png"> + <link rel="apple-touch-icon-precomposed" sizes="72x72" href="/img/ico/apple-touch-icon-72.png"> + <link rel="apple-touch-icon-precomposed" href="/img/ico/apple-touch-icon-57.png"> + + +</head> + + +<body class=""> + <header id="page-head"> + <div id="topbar" class="container"> + <div class="row"> + <div class="span2"> + <h1 id="logo"><a href="/" title="99s">99s</a></h1> + </div> + <div class="span10"> + + <div id="side-header"> + <nav> + <ul> + <li><a title="Hear my thoughts" href="/articles">Articles</a></li> + <li><a title="Watch my talks" href="/talks">Talks</a></li> + <li class="active"><a title="Read the docs" href="/docs">Documentation</a></li> + <li><a title="Request my services" href="/services">Consulting & Training</a></li> + </ul> + </nav> + <ul id="social"> + <li> + <a href="https://github.com/ninenines" title="Check my Github repositories"><img src="/img/ico_github.png" data-hover="/img/ico_github_alt.png" alt="Github"></a> + </li> + <li> + <a title="Contact me" href="mailto:[email protected]"><img src="/img/ico_mail.png" data-hover="/img/ico_mail_alt.png"></a> + </li> + </ul> + </div> + </div> + </div> + </div> + + +</header> + +<div id="contents" class="two_col"> +<div class="container"> +<div class="row"> +<div id="docs" class="span9 maincol"> + +<h1 class="lined-header"><span>Erlang and the Web</span></h1> + +<div class="paragraph"><p>Erlang is the ideal platform for writing Web applications. +Its features are a perfect match for the requirements of +modern Web applications.</p></div> +<div class="sect1"> +<h2 id="_the_web_is_concurrent">The Web is concurrent</h2> +<div class="sectionbody"> +<div class="paragraph"><p>When you access a website there is little concurrency +involved. A few connections are opened and requests +are sent through these connections. Then the web page +is displayed on your screen. Your browser will only +open up to 4 or 8 connections to the server, depending +on your settings. This isn’t much.</p></div> +<div class="paragraph"><p>But think about it. You are not the only one accessing +the server at the same time. There can be hundreds, if +not thousands, if not millions of connections to the +same server at the same time.</p></div> +<div class="paragraph"><p>Even today a lot of systems used in production haven’t +solved the C10K problem (ten thousand concurrent connections). +And the ones who did are trying hard to get to the next +step, C100K, and are pretty far from it.</p></div> +<div class="paragraph"><p>Erlang meanwhile has no problem handling millions of +connections. At the time of writing there are application +servers written in Erlang that can handle more than two +million connections on a single server in a real production +application, with spare memory and CPU!</p></div> +<div class="paragraph"><p>The Web is concurrent, and Erlang is a language designed +for concurrency, so it is a perfect match.</p></div> +<div class="paragraph"><p>Of course, various platforms need to scale beyond a few +million connections. This is where Erlang’s built-in +distribution mechanisms come in. If one server isn’t +enough, add more! Erlang allows you to use the same code +for talking to local processes or to processes in other +parts of your cluster, which means you can scale very +quickly if the need arises.</p></div> +<div class="paragraph"><p>The Web has large userbases, and the Erlang platform was +designed to work in a distributed setting, so it is a +perfect match.</p></div> +<div class="paragraph"><p>Or is it? Surely you can find solutions to handle that many +concurrent connections with your favorite language… But all +these solutions will break down in the next few years. Why? +Firstly because servers don’t get any more powerful, they +instead get a lot more cores and memory. This is only useful +if your application can use them properly, and Erlang is +light-years away from anything else in that area. Secondly, +today your computer and your phone are online, tomorrow your +watch, goggles, bike, car, fridge and tons of other devices +will also connect to various applications on the Internet.</p></div> +<div class="paragraph"><p>Only Erlang is prepared to deal with what’s coming.</p></div> +</div> +</div> +<div class="sect1"> +<h2 id="_the_web_is_soft_real_time">The Web is soft real time</h2> +<div class="sectionbody"> +<div class="paragraph"><p>What does soft real time mean, you ask? It means we want the +operations done as quickly as possible, and in the case of +web applications, it means we want the data propagated fast.</p></div> +<div class="paragraph"><p>In comparison, hard real time has a similar meaning, but also +has a hard time constraint, for example an operation needs to +be done in under N milliseconds otherwise the system fails +entirely.</p></div> +<div class="paragraph"><p>Users aren’t that needy yet, they just want to get access +to their content in a reasonable delay, and they want the +actions they make to register at most a few seconds after +they submitted them, otherwise they’ll start worrying about +whether it successfully went through.</p></div> +<div class="paragraph"><p>The Web is soft real time because taking longer to perform an +operation would be seen as bad quality of service.</p></div> +<div class="paragraph"><p>Erlang is a soft real time system. It will always run +processes fairly, a little at a time, switching to another +process after a while and preventing a single process to +steal resources from all others. This means that Erlang +can guarantee stable low latency of operations.</p></div> +<div class="paragraph"><p>Erlang provides the guarantees that the soft real time Web +requires.</p></div> +</div> +</div> +<div class="sect1"> +<h2 id="_the_web_is_asynchronous">The Web is asynchronous</h2> +<div class="sectionbody"> +<div class="paragraph"><p>Long ago, the Web was synchronous because HTTP was synchronous. +You fired a request, and then waited for a response. Not anymore. +It all began when XmlHttpRequest started being used. It allowed +the client to perform asynchronous calls to the server.</p></div> +<div class="paragraph"><p>Then Websocket appeared and allowed both the server and the client +to send data to the other endpoint completely asynchronously. The +data is contained within frames and no response is necessary.</p></div> +<div class="paragraph"><p>Erlang processes work the same. They send each other data contained +within messages and then continue running without needing a response. +They tend to spend most of their time inactive, waiting for a new +message, and the Erlang VM happily activate them when one is received.</p></div> +<div class="paragraph"><p>It is therefore quite easy to imagine Erlang being good at receiving +Websocket frames, which may come in at unpredictable times, pass the +data to the responsible processes which are always ready waiting for +new messages, and perform the operations required by only activating +the required parts of the system.</p></div> +<div class="paragraph"><p>The more recent Web technologies, like Websocket of course, but also +HTTP/2.0, are all fully asynchronous protocols. The concept +of requests and responses is retained of course, but anything could +be sent in between, by both the client or the browser, and the +responses could also be received in a completely different order.</p></div> +<div class="paragraph"><p>Erlang is by nature asynchronous and really good at it thanks to the +great engineering that has been done in the VM over the years. It’s +only natural that it’s so good at dealing with the asynchronous Web.</p></div> +</div> +</div> +<div class="sect1"> +<h2 id="_the_web_is_omnipresent">The Web is omnipresent</h2> +<div class="sectionbody"> +<div class="paragraph"><p>The Web has taken a very important part of our lives. We’re +connected at all times, when we’re on our phone, using our computer, +passing time using a tablet while in the bathroom… And this +isn’t going to slow down, every single device at home or on us +will be connected.</p></div> +<div class="paragraph"><p>All these devices are always connected. And with the number of +alternatives to give you access to the content you seek, users +tend to not stick around when problems arise. Users today want +their applications to be always available and if it’s having +too many issues they just move on.</p></div> +<div class="paragraph"><p>Despite this, when developers choose a product to use for building +web applications, their only concern seems to be "Is it fast?", +and they look around for synthetic benchmarks showing which one +is the fastest at sending "Hello world" with only a handful +concurrent connections. Web benchmarks haven’t been representative +of reality in a long time, and are drifting further away as +time goes on.</p></div> +<div class="paragraph"><p>What developers should really ask themselves is "Can I service +all my users with no interruption?" and they’d find that they have +two choices. They can either hope for the best, or they can use +Erlang.</p></div> +<div class="paragraph"><p>Erlang is built for fault tolerance. When writing code in any other +language, you have to check all the return values and act accordingly +to avoid any unforeseen issues. If you’re lucky, you won’t miss +anything important. When writing Erlang code, you can just check +the success condition and ignore all errors. If an error happens, +the Erlang process crashes and is then restarted by a special +process called a supervisor.</p></div> +<div class="paragraph"><p>Erlang developers thus have no need to fear unhandled +errors, and can focus on handling only the errors that should +give some feedback to the user and let the system take care of +the rest. This also has the advantage of allowing them to write +a lot less code, and let them sleep at night.</p></div> +<div class="paragraph"><p>Erlang’s fault tolerance oriented design is the first piece of +what makes it the best choice for the omnipresent, always available +Web.</p></div> +<div class="paragraph"><p>The second piece is Erlang’s built-in distribution. Distribution +is a key part of building a fault tolerant system, because it +allows you to handle bigger failures, like a whole server going +down, or even a data center entirely.</p></div> +<div class="paragraph"><p>Fault tolerance and distribution are important today, and will be +vital in the future of the Web. Erlang is ready.</p></div> +</div> +</div> +<div class="sect1"> +<h2 id="_learn_erlang">Learn Erlang</h2> +<div class="sectionbody"> +<div class="paragraph"><p>If you are new to Erlang, you may want to grab a book or +two to get started. Those are my recommendations as the +author of Cowboy.</p></div> +<div class="sect3"> +<h4 id="_the_erlanger_playbook">The Erlanger Playbook</h4> +<div class="paragraph"><p>The Erlanger Playbook is an ebook I am currently writing, +which covers a number of different topics from code to +documentation to testing Erlang applications. It also has +an Erlang section where it covers directly the building +blocks and patterns, rather than details like the syntax.</p></div> +<div class="paragraph"><p>You can most likely read it as a complete beginner, but +you will need a companion book to make the most of it. +Buy it from the <a href="https://ninenines.eu">Nine Nines website</a>.</p></div> +</div> +<div class="sect3"> +<h4 id="_programming_erlang">Programming Erlang</h4> +<div class="paragraph"><p>This book is from one of the creator of Erlang, Joe +Armstrong. It provides a very good explanation of what +Erlang is and why it is so. It serves as a very good +introduction to the language and platform.</p></div> +<div class="paragraph"><p>The book is <a href="http://pragprog.com/book/jaerlang2/programming-erlang">Programming Erlang</a>, +and it also features a chapter on Cowboy.</p></div> +</div> +<div class="sect3"> +<h4 id="_learn_you_some_erlang_for_great_good">Learn You Some Erlang for Great Good!</h4> +<div class="paragraph"><p><a href="http://learnyousomeerlang.com">LYSE</a> is a much more complete +book covering many aspects of Erlang, while also providing +stories and humor. Be warned: it’s pretty verbose. It comes +with a free online version and a more refined paper and +ebook version.</p></div> +</div> +</div> +</div> + + + + + + + + + + + <nav style="margin:1em 0"> + + <a style="float:left" href="https://ninenines.eu/docs/en/cowboy/2.4/guide/modern_web/"> + The modern Web + </a> + + + + <a style="float:right" href="https://ninenines.eu/docs/en/cowboy/2.4/guide/introduction/"> + Introduction + </a> + + </nav> + + + + +</div> + +<div class="span3 sidecol"> + + +<h3> + Cowboy + 2.4 + + User Guide +</h3> + +<ul> + + <li><a href="/docs/en/cowboy/2.4/guide">User Guide</a></li> + + + <li><a href="/docs/en/cowboy/2.4/manual">Function Reference</a></li> + + +</ul> + +<h4 id="docs-nav">Navigation</h4> + +<h4>Version select</h4> +<ul> + + + + <li><a href="/docs/en/cowboy/2.4/guide">2.4</a></li> + + <li><a href="/docs/en/cowboy/2.3/guide">2.3</a></li> + + <li><a href="/docs/en/cowboy/2.2/guide">2.2</a></li> + + <li><a href="/docs/en/cowboy/2.1/guide">2.1</a></li> + + <li><a href="/docs/en/cowboy/2.0/guide">2.0</a></li> + + <li><a href="/docs/en/cowboy/1.0/guide">1.0</a></li> + +</ul> + +</div> +</div> +</div> +</div> + + <footer> + <div class="container"> + <div class="row"> + <div class="span6"> + <p id="scroll-top"><a href="#">↑ Scroll to top</a></p> + <nav> + <ul> + <li><a href="mailto:[email protected]" title="Contact us">Contact us</a></li><li><a href="https://github.com/ninenines/ninenines.github.io" title="Github repository">Contribute to this site</a></li> + </ul> + </nav> + </div> + <div class="span6 credits"> + <p><img src="/img/footer_logo.png"></p> + <p>Copyright © Loïc Hoguin 2012-2018</p> + </div> + </div> + </div> + </footer> + + + <script src="/js/custom.js"></script> + </body> +</html> + + |