blob: dc74c15126a8986e1221c14b2d44c2523fa823ac [file] [log] [blame]
<!doctype html>
<!--
Minimal Mistakes Jekyll Theme 4.4.1 by Michael Rose
Copyright 2017 Michael Rose - mademistakes.com | @mmistakes
Free for personal and commercial use under the MIT license
https://github.com/mmistakes/minimal-mistakes/blob/master/LICENSE.txt
-->
<html lang="en" class="no-js">
<head>
<meta charset="utf-8">
<!-- begin SEO -->
<title>Eventual Data Consistency Solution in ServiceComb - part 2 - Apache ServiceComb</title>
<meta name="description" content="The design of distributed saga in ServiceComb">
<meta name="author" content="Sean Yin">
<meta property="og:locale" content="en">
<meta property="og:site_name" content="Apache ServiceComb">
<meta property="og:title" content="Eventual Data Consistency Solution in ServiceComb - part 2">
<link rel="canonical" href="https://github.com/pages/apache/incubator-servicecomb-website/docs/distributed_saga_2/">
<meta property="og:url" content="https://github.com/pages/apache/incubator-servicecomb-website/docs/distributed_saga_2/">
<meta property="og:description" content="The design of distributed saga in ServiceComb">
<meta name="twitter:site" content="@ServiceComb">
<meta name="twitter:title" content="Eventual Data Consistency Solution in ServiceComb - part 2">
<meta name="twitter:description" content="The design of distributed saga in ServiceComb">
<meta name="twitter:url" content="">
<meta name="twitter:card" content="summary">
<meta name="twitter:creator" content="@seanyinx">
<meta property="og:type" content="article">
<meta property="article:published_time" content="2017-09-16T00:00:00+08:00">
<script type="application/ld+json">
{
"@context" : "http://schema.org",
"@type" : "Person",
"name" : "Apache ServiceComb",
"url" : "https://github.com/pages/apache/incubator-servicecomb-website",
"sameAs" : null
}
</script>
<meta name="google-site-verification" content="HvJjNd7vvJ-yjSTHlBiIWEYxp_Hrz-PYEY5Idz9LRcA" />
<!-- end SEO -->
<link href="/feed.xml" type="application/atom+xml" rel="alternate" title="Apache ServiceComb Feed">
<!-- http://t.co/dKP3o1e -->
<meta name="HandheldFriendly" content="True">
<meta name="MobileOptimized" content="320">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<script>
document.documentElement.className = document.documentElement.className.replace(/\bno-js\b/g, '') + ' js ';
</script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/clipboard.js/1.7.1/clipboard.min.js"></script>
<script src="/assets/vendor/prism/prism.js"></script>
<script type="text/javascript" async
src="https://cdnjs.cloudflare.com/ajax/libs/mathjax/2.7.1/MathJax.js?config=TeX-MML-AM_CHTML">
</script>
<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0-beta/css/bootstrap.min.css" integrity="sha384-/Y6pD6FV/Vv2HJnA6t+vslU6fwYXjCFtcEpHbNJ0lyAFsXTsjBbfaDjzALeQsN6M" crossorigin="anonymous">
<script src="https://code.jquery.com/jquery-3.2.1.slim.min.js" integrity="sha384-KJ3o2DKtIkvYIK3UENzmM7KCkRr/rE9/Qpg6aAZGJwFDMVNA/GpGFF93hXpG5KkN" crossorigin="anonymous"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.11.0/umd/popper.min.js" integrity="sha384-b/U6ypiBEHpOf/4+1nzFpr53nxSS+GLCkfwBdFNTxtclqqenISfwAzpKaMNFNmj4" crossorigin="anonymous"></script>
<script src="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0-beta/js/bootstrap.min.js" integrity="sha384-h0AbiXch4ZDo7tp9hKZ4TsHbi047NrKGLO3SEJAg45jXxnGIfYzk4Si90RDIqNm1" crossorigin="anonymous"></script>
<!-- For all browsers -->
<link rel="stylesheet" href="/assets/css/main.css?v=1">
<link rel="stylesheet" href="/assets/vendor/prism/prism.css?v=1">
<!--[if lte IE 9]>
<style>
/* old IE unsupported flexbox fixes */
.greedy-nav .site-title {
padding-right: 3em;
}
.greedy-nav button {
position: absolute;
top: 0;
right: 0;
height: 100%;
}
</style>
<![endif]-->
<meta http-equiv="cleartype" content="on">
<!-- start custom head snippets -->
<!-- insert favicons. use http://realfavicongenerator.net/ -->
<link href="https://fonts.cat.net/css?family=Roboto:400,500,700|Source+Code+Pro" rel="stylesheet">
<script src="/assets/js/custom.js"></script>
<!-- end custom head snippets -->
</head>
<body class="layout--single">
<!--[if lt IE 9]>
<div class="notice--danger align-center" style="margin: 0;">You are using an <strong>outdated</strong> browser. Please <a href="http://browsehappy.com/">upgrade your browser</a> to improve your experience.</div>
<![endif]-->
<div class="masthead" onmouseleave="$('#childrenShow').css('display', 'none')">
<div class="masthead__inner-wrap">
<div class="masthead__menu">
<nav id="site-nav" class="greedy-nav">
<a class="site-title active" href="/"><img src="https://www.apache.org/img/servicecomb.png"></a>
<ul class="visible-links">
<li class="masthead__menu-item" onmouseenter="$('#childrenShow').css('display', 'none')">
<a href="/">Home</a>
</li>
<li class="masthead__menu-item" onmouseenter="$('#childrenShow').css('display', 'none')">
<a href="/developers/">Projects</a>
</li>
<li class="def-nav-li" onmouseenter="$('#childrenShow').css('display', 'block')">
<a href="/docs/users/">Documentation</a>
<ul id="childrenShow" class="def-children-show-en" onmouseleave="$('#childrenShow').css('display', 'none')">
<li><a href="/docs/getting-started/" class="">Getting started</a></li>
<li><a href="/docs/users/" class="">Docs</a></li>
<li><a href="/slides/" class="">Video</a></li>
<li><a href="/faqs/" class="">FAQ</a></li>
</ul>
</li>
<li class="masthead__menu-item" onmouseenter="$('#childrenShow').css('display', 'none')">
<a href="/developers/contributing">Community</a>
</li>
<li class="masthead__menu-item" onmouseenter="$('#childrenShow').css('display', 'none')">
<a href="/year-archive/">Blogs</a>
</li>
<li class="masthead__menu-item" onmouseenter="$('#childrenShow').css('display', 'none')">
<a href="/release/">Downloads</a>
</li>
</ul>
<button><div class="navicon"></div></button>
<ul class="hidden-links hidden"></ul>
<div class="nav-lang">
<a href=/cn/docs/distributed_saga_2/>中文</a>
</div>
</nav>
</div>
</div>
</div>
<div id="main" role="main">
<div class="sidebar sticky">
<div class="back-to-home"><a href="/">Home</a> > Eventual Data Consistency Solution in ServiceComb - part 2</div>
<div itemscope itemtype="http://schema.org/Person">
<div class="author__content">
<h3 class="author__name" itemprop="name">Sean Yin</h3>
<p class="author__bio" itemprop="description">
Nothing but speed is indestructible
</p>
</div>
<div class="author__urls-wrapper">
<button class="btn btn--inverse">Follow</button>
<ul class="author__urls social-icons">
<li>
<a href="http://seanyinx.github.io" itemprop="url">
<i class="fa fa-fw fa-chain" aria-hidden="true"></i> Website
</a>
</li>
<li>
<a href="mailto:seanyinx@gmail.com">
<meta itemprop="email" content="seanyinx@gmail.com" />
<i class="fa fa-fw fa-envelope-square" aria-hidden="true"></i> Email
</a>
</li>
<li>
<a href="https://twitter.com/seanyinx" itemprop="sameAs">
<i class="fa fa-fw fa-twitter-square" aria-hidden="true"></i> Twitter
</a>
</li>
<!--
<li>
<a href="http://link-to-whatever-social-network.com/user/" itemprop="sameAs">
<i class="fa fa-fw" aria-hidden="true"></i> Custom Social Profile Link
</a>
</li>
-->
</ul>
</div>
</div>
</div>
<article class="page" itemscope itemtype="http://schema.org/CreativeWork">
<meta itemprop="headline" content="Eventual Data Consistency Solution in ServiceComb - part 2">
<meta itemprop="description" content="The design of distributed saga in ServiceComb">
<meta itemprop="datePublished" content="September 16, 2017">
<meta itemprop="dateModified" content="September 16, 2017">
<div class="page__inner-wrap">
<header>
<h1 class="page__title" itemprop="headline">Eventual Data Consistency Solution in ServiceComb - part 2
</h1>
<p class="page__meta"><i class="fa fa-clock-o" aria-hidden="true"></i>
4 minute read
</p>
</header>
<section class="page__content" itemprop="text">
<p>In my <a href="/docs/distributed_saga_1/">previous post</a>, I talked about how <a href="https://www.cs.cornell.edu/andru/cs711/2002fa/reading/sagas.pdf">Saga</a> can
be used to solve the data consistency issue of our trip planning application. Now let's gather the requirements to design
a saga.</p>
<h2 id="saga-log">Saga Log</h2>
<p>Saga guarantees either all sub-transactions are committed or compensated for, but the saga system itself may crash. There
are a few states that a saga may be in on crash:</p>
<ul>
<li>Saga received a request, but no transaction started yet. States of services involved in sub-transactions are not modified
by saga, nothing has been done.</li>
<li>Some sub-transactions were done. When restarted, saga has to resume from the last completed transaction.</li>
<li>A sub-transaction was started, but not completed yet. Since we are not sure if the remote service completed the transaction,
failed the transaction, or the request to remote service timed out, saga has to redo the sub-transaction on restart. That also
means sub-transactions have to be idempotent.</li>
<li>A sub-transaction failed and its compensating transaction has not started yet. Saga has to resume from the compensating
transaction on restart.</li>
<li>A compensating transaction started but not completed yet. The solution is basically the same as the previous one. That means
compensating transactions have to idempotent too.</li>
<li>All sub-transactions or compensating transactions were done, which is the same as the first case.</li>
</ul>
<p>In order for saga to recover to the states mentioned above, we have to keep track of each step of sub-transactions and
compensating transactions. We decided to achieve that by saving the following events in a persistent store called saga log:</p>
<ul>
<li><strong>Saga started event</strong> stores the entire saga request, which includes multiple transaction/compensation requests</li>
<li><strong>Transaction started event</strong> stores individual transaction request</li>
<li><strong>Transaction ended event</strong> stores individual transaction request and its response</li>
<li><strong>Transaction aborted event</strong> stores individual transaction request and the cause of failure</li>
<li><strong>Transaction compensated event</strong> stores individual compensation request and its response</li>
<li><strong>Saga ended event</strong> marks the end of a saga request and stores nothing</li>
</ul>
<p><img src="/assets/images/saga.events.png" alt="Events" class="align-center" /></p>
<p>By persisting these events in saga log, a crashed saga can be recovered to any states above.</p>
<p>Since saga only needs persistence of events and the event contents are stored as JSON, the implementation of the saga log
is very flexible. Databases (SQL or NoSQL), durable message queues, or even plain files can be used as event storage, but
some are faster for saga to recover.</p>
<h2 id="request-data-structure-of-saga">Request Data Structure of Saga</h2>
<p>In our case, flight booking, car rental, and hotel reservation have no dependency among each other at all and they can be
processed in parallel. However, it's more user friendly for our customers to only charge their credit cards once, when all
the bookings are done successfully. That means the transactions of the four services look like the graph below.</p>
<p><img src="/assets/images/saga.transactions.png" alt="Transactions" class="align-center" /></p>
<p>It makes sense to implement the data structure of trip planning request as a <a href="https://en.wikipedia.org/wiki/Directed_acyclic_graph">Directed Acyclic Graph</a>.
The root of the graph is saga start task and the leaf is saga end task.</p>
<p><img src="/assets/images/saga.graph.png" alt="Request Graph" class="align-center" /></p>
<h2 id="parallel-saga">Parallel Saga</h2>
<p>As mentioned above, flight booking, car rental, and hotel reservation can be processed in parallel. But doing so creates
another problem: what if flight booking failed while car rental is being processed? We can't keep waiting for the response
from car rental service, because we have no idea how long it will take.</p>
<p>THe best thing we can do is to send the car rental request again and hope we get a response so that we can continue our
backward recovery. If car rental service never responds, we may have to fallback with manual intervention.</p>
<p>The delayed booking request may still be received by the remote car rental service. When it does, the service has already
processed the same booking and its cancellation request.</p>
<p><img src="/assets/images/saga.commutative.png" alt="Network Latency" class="align-center" /></p>
<p>Therefore, services have to implement transactions and compensations in such a way that transaction request received after
its compensation request takes no effect. Caitie McCaffrey called this <strong>commutative compensating request</strong> in her talk
on <a href="https://www.youtube.com/watch?v=1H6tounpnG8">Distributed Sagas: A Protocol for Coordinating Microservices</a>.</p>
<h2 id="acid-and-saga">ACID and Saga</h2>
<p><a href="https://en.wikipedia.org/wiki/ACID">ACID</a> is consistency model with the following properties:</p>
<ul>
<li>Atomicity</li>
<li>Consistency</li>
<li>Isolation</li>
<li>Durability</li>
</ul>
<p>Saga does not provide ACID guarantee, because atomicity and isolation are not satisfied according to the <a href="https://www.cs.cornell.edu/andru/cs711/2002fa/reading/sagas.pdf">paper</a></p>
<blockquote>
<p>full atomicity is not provided. That is, sagas may view the partial results of other sagas [<a href="https://www.cs.cornell.edu/andru/cs711/2002fa/reading/sagas.pdf">1</a>]</p>
</blockquote>
<p>With durable saga log, saga guarantees consistency and durability.</p>
<h2 id="saga-architecture">Saga Architecture</h2>
<p>Finally, the architecture of our saga looks like this</p>
<p><img src="/assets/images/saga.design.png" alt="Saga Architecture" class="align-center" /></p>
<ul>
<li>Saga execution component parses the request JSON and builds a graph of requests</li>
<li>TaskRunner ensures the execution order of requests with task queue</li>
<li>TaskConsumer processes tasks to write events to saga log and send requests to remote services</li>
</ul>
<h2 id="summary">Summary</h2>
<p>In this article, we talked about how saga can be implemented with a saga log to persist transaction/compensation events
and request graph. A crashed saga can also be recovered from all the persisted events in saga log on restart. However,
there are a few requirements on design of microservices to ensure saga consistency guarantee:</p>
<ul>
<li>transaction and compensation requests must be idempotent</li>
<li>compensation requests must be commutative</li>
</ul>
<h2 id="references">References</h2>
<ol>
<li><a href="https://www.cs.cornell.edu/andru/cs711/2002fa/reading/sagas.pdf">Original Paper on Sagas</a> by By Hector Garcia-Molina &amp; Kenneth Salem</li>
</ol>
</section>
<footer class="page__meta">
<p class="page__taxonomy">
<strong><i class="fa fa-fw fa-tags" aria-hidden="true"></i> Tags: </strong>
<span itemprop="keywords">
<a href="/tags/#saga" class="page__taxonomy-item" rel="tag">saga</a>
</span>
</p>
<p class="page__date"><strong><i class="fa fa-fw fa-calendar" aria-hidden="true"></i> Updated:</strong> <time datetime="2017-09-16">September 16, 2017</time></p>
</footer>
<section class="page__share">
<h4 class="page__share-title">Share on</h4>
<a href="https://twitter.com/intent/tweet?via=ServiceComb&text=Eventual Data Consistency Solution in ServiceComb - part 2 /docs/distributed_saga_2/" class="btn btn--twitter" title="Share on Twitter"><i class="fa fa-fw fa-twitter" aria-hidden="true"></i><span> Twitter</span></a>
<a href="https://www.facebook.com/sharer/sharer.php?u=/docs/distributed_saga_2/" class="btn btn--facebook" title="Share on Facebook"><i class="fa fa-fw fa-facebook" aria-hidden="true"></i><span> Facebook</span></a>
<a href="https://plus.google.com/share?url=/docs/distributed_saga_2/" class="btn btn--google-plus" title="Share on Google Plus"><i class="fa fa-fw fa-google-plus" aria-hidden="true"></i><span> Google+</span></a>
<a href="https://www.linkedin.com/shareArticle?mini=true&url=/docs/distributed_saga_2/" class="btn btn--linkedin" title="Share on LinkedIn"><i class="fa fa-fw fa-linkedin" aria-hidden="true"></i><span> LinkedIn</span></a>
</section>
<nav class="pagination">
<a href="/cn/docs/performance-test-on-seckill-with-jmeter/" class="pagination--pager" title="使用JMeter对秒杀示例进行性能测试
">Previous</a>
<a href="/cn/docs/distributed_saga_2/" class="pagination--pager" title="ServiceComb中的数据最终一致性方案 - part 2
">Next</a>
</nav>
</div>
<div class="page__comments">
<section id="static-comments">
<!-- Start static comments -->
<div class="js-comments">
</div>
<!-- End static comments -->
<!-- Start new comment form -->
<h4 class="page__comments-title">Leave a Comment</h4>
<p class="small">Your email address will not be published. Required fields are marked <span class="required">*</span></p>
<form id="new_comment" class="page__comments-form js-form form" method="post" action="https://api.staticman.net/v1/entry/apache/incubator-servicecomb-website/master">
<div class="form__spinner">
<i class="fa fa-spinner fa-spin fa-3x fa-fw"></i>
<span class="sr-only">Loading...</span>
</div>
<fieldset>
<label for="comment-form-message">Comment <small class="required">*</small></label>
<textarea type="text" rows="3" id="comment-form-message" name="fields[message]" tabindex="1"></textarea>
<div class="small help-block"><a href="https://daringfireball.net/projects/markdown/">Markdown is supported.</a></div>
</fieldset>
<fieldset>
<label for="comment-form-name">Name <small class="required">*</small></label>
<input type="text" id="comment-form-name" name="fields[name]" tabindex="2" />
</fieldset>
<fieldset>
<label for="comment-form-email">Email address <small class="required">*</small></label>
<input type="email" id="comment-form-email" name="fields[email]" tabindex="3" />
</fieldset>
<fieldset>
<label for="comment-form-url">Website (optional)</label>
<input type="url" id="comment-form-url" name="fields[url]" tabindex="4"/>
</fieldset>
<fieldset class="hidden" style="display: none;">
<input type="hidden" name="options[slug]" value="saga-design">
<label for="comment-form-location">Not used. Leave blank if you are a human.</label>
<input type="text" id="comment-form-location" name="fields[hidden]" autocomplete="off"/>
</fieldset>
<!-- Start comment form alert messaging -->
<p class="hidden js-notice">
<strong class="js-notice-text"></strong>
</p>
<!-- End comment form alert messaging -->
<fieldset>
<button type="submit" id="comment-form-submit" tabindex="5" class="btn btn--large">Submit Comment</button>
</fieldset>
</form>
<!-- End new comment form -->
</section>
</div>
</article>
<div class="page__related">
<h4 class="page__related-title">You May Also Enjoy</h4>
<div class="grid__wrapper">
<div class="grid__item">
<article class="archive__item" itemscope itemtype="http://schema.org/CreativeWork">
<h2 class="archive__item-title" itemprop="headline">
<a href="/cn/docs/playing-on-the-open-source-community-with-Apache-ServiceComb-GDUT/" rel="permalink">与Apache ServiceComb一起玩开源-广工站 (PPT Download)
</a>
</h2>
<p class="archive__item-excerpt" itemprop="description">与Apache ServiceComb一起玩开源-广工站 (PPT Download)
</p>
<p class="page__meta"><i class="fa fa-clock-o" aria-hidden="true"></i>
less than 1 minute read
</p>
</article>
</div>
<div class="grid__item">
<article class="archive__item" itemscope itemtype="http://schema.org/CreativeWork">
<h2 class="archive__item-title" itemprop="headline">
<a href="/cn/docs/servicecomb-service-center-client/" rel="permalink">使用ServiceComb客户端轻松调用ServiceCenter
</a>
</h2>
<p class="archive__item-excerpt" itemprop="description">使用ServiceComb客户端轻松调用ServiceCenter
</p>
<p class="page__meta"><i class="fa fa-clock-o" aria-hidden="true"></i>
2 minute read
</p>
</article>
</div>
<div class="grid__item">
<article class="archive__item" itemscope itemtype="http://schema.org/CreativeWork">
<h2 class="archive__item-title" itemprop="headline">
<a href="/cn/docs/playing-on-the-open-source-community-with-Apache-ServiceComb-BUPT/" rel="permalink">与Apache ServiceComb一起玩开源-北邮站 (PPT Download)
</a>
</h2>
<p class="archive__item-excerpt" itemprop="description">与Apache ServiceComb一起玩开源-北邮站 (PPT Download)
</p>
<p class="page__meta"><i class="fa fa-clock-o" aria-hidden="true"></i>
less than 1 minute read
</p>
</article>
</div>
<div class="grid__item">
<article class="archive__item" itemscope itemtype="http://schema.org/CreativeWork">
<h2 class="archive__item-title" itemprop="headline">
<a href="/docs/servicecomb-accept-newcapec-institute-code-donation/" rel="permalink">Apache ServiceComb Accept Code Donation From NewCapec Institute
</a>
</h2>
<p class="archive__item-excerpt" itemprop="description">Apache ServiceComb Accept Code Donation From NewCapec Institute
</p>
<p class="page__meta"><i class="fa fa-clock-o" aria-hidden="true"></i>
less than 1 minute read
</p>
</article>
</div>
</div>
</div>
</div>
<script async src="//pagead2.googlesyndication.com/pagead/js/adsbygoogle.js"></script>
<div align="center" style="margin: 0 0;">
<ins class="adsbygoogle"
style="display:block; border-bottom: initial;"
data-ad-client="ca-pub-7328585512091257"
data-ad-slot="3049671934"
data-ad-format="auto"></ins>
</div>
<div class="page__footer">
<footer>
<!-- start custom footer snippets -->
<!-- end custom footer snippets -->
<div class="container">
<div class="row justify-content-md-center">
<div class="col">
<ul>
<p class="header">Resources</p>
<li><a href="/docs/getting-started/">Getting started</a></li>
<li><a href="/docs/users/">User Guide</a></li>
<li><a href="/slides/">Slides</a></li>
<li><a href="/users/faq/">Common Questions</a></li>
</ul>
</div>
<div class="col">
<ul>
<p class="header">ASF</p>
<li><a href="http://www.apache.org">Foundation</a></li>
<li><a href="http://www.apache.org/licenses/">License</a></li>
<li><a href="http://www.apache.org/events/current-event">Events</a></li>
<li><a href="http://www.apache.org/foundation/sponsorship.html">Sponsorship</a></li>
<li><a href="http://www.apache.org/foundation/thanks.html">Thanks</a></li>
</ul>
</div>
<div class="col">
<ul>
<p class="header">Contribute</p>
<li><a href="http://issues.apache.org/jira/browse/SCB">Report a Doc Issue</a></li>
<li><a href="https://github.com/apache/servicecomb-website/edit/master/_posts/2017-09-16-saga-design.md">Edit This Page on Github</a></li>
<li><a href="/developers/submit-codes/">Code Submit Guide</a></li>
<li><a href="/security">Security</a></li>
</ul>
</div>
<div class="col">
<ul class="social-icons">
<p class="header">Community</p>
<li>
<a href="mailto:dev-subscribe@servicecomb.incubator.apache.org" rel="nofollow"><span class="mail">Mailing List</span></a>
</li>
<li>
<a href="https://github.com/apache?q=ServiceComb" target="_blank"><span class="github">Github</span></a>
</li>
<li>
<a href="https://twitter.com/ServiceComb" target="_blank"><span class="twitter">Twitter</span></a>
</li>
<li>
<a href="/feed.xml" target="_blank"><span class="rss">Feed</span></a>
</li>
</ul>
</div>
</div>
</div>
<div class="page__footer-bottom">
<div>&copy; 2019 Apache ServiceComb. Powered by <a href="http://jekyllrb.com" rel="nofollow">Jekyll</a> &amp; <a href="https://mademistakes.com/work/minimal-mistakes-jekyll-theme/" rel="nofollow">Minimal Mistakes</a>.</div>
<div>All other marks mentioned may be trademarks or registered trademarks of their respective owners.</div>
</div>
</footer>
</div>
<script src="/assets/js/main.min.js"></script>
<script>
(function(i,s,o,g,r,a,m){i['GoogleAnalyticsObject']=r;i[r]=i[r]||function(){
(i[r].q=i[r].q||[]).push(arguments)},i[r].l=1*new Date();a=s.createElement(o),
m=s.getElementsByTagName(o)[0];a.async=1;a.src=g;m.parentNode.insertBefore(a,m)
})(window,document,'script','https://www.google-analytics.com/analytics.js','ga');
ga('create', 'UA-101622733-1', 'auto');
ga('send', 'pageview');
</script>
<script>
(function ($) {
var $comments = $('.js-comments');
$('#new_comment').submit(function () {
var form = this;
$(form).addClass('disabled');
$('#comment-form-submit').html('<i class="fa fa-spinner fa-spin fa-fw"></i> Loading...');
$.ajax({
type: $(this).attr('method'),
url: $(this).attr('action'),
data: $(this).serialize(),
contentType: 'application/x-www-form-urlencoded',
success: function (data) {
$('#comment-form-submit').html('Submitted');
$('.page__comments-form .js-notice').removeClass('notice--danger');
$('.page__comments-form .js-notice').addClass('notice--success');
showAlert('Thanks for your comment! It will show on the site once it has been approved.');
},
error: function (err) {
console.log(err);
$('#comment-form-submit').html('Submit Comment');
$('.page__comments-form .js-notice').removeClass('notice--success');
$('.page__comments-form .js-notice').addClass('notice--danger');
showAlert('Sorry, there was an error with your submission. Please make sure all required fields have been completed and try again.');
$(form).removeClass('disabled');
}
});
return false;
});
function showAlert(message) {
$('.page__comments-form .js-notice').removeClass('hidden');
$('.page__comments-form .js-notice-text').html(message);
}
})(jQuery);
</script>
</body>
</html>