2936 lines
131 KiB
HTML
2936 lines
131 KiB
HTML
<!DOCTYPE html>
|
||
<html lang="en">
|
||
<head>
|
||
<meta charset="utf-8">
|
||
<meta http-equiv="X-UA-Compatible" content="IE=edge,chrome=1">
|
||
<meta name="viewport" content="width=device-width, initial-scale=1">
|
||
<meta name="description" content="An overview of how developers and data scientists can use various transaction models (exactly-once, at-least-once, etc.) out of the box with Apache Kafka.">
|
||
<meta name="keywords" content="kafka, semantics, application, Transaction log">
|
||
|
||
<meta property="og:description" content="An overview of how developers and data scientists can use various transaction models (exactly-once, at-least-once, etc.) out of the box with Apache Kafka.">
|
||
<meta property="og:site_name" content="dzone.com">
|
||
<meta property="og:title" content="Interpreting Kafka's Exactly-Once Semantics">
|
||
<meta property="og:url" content="https://dzone.com/articles/interpreting-kafkas-exactly-once-semantics">
|
||
<meta property="og:image" content="https://dz2cdn1.dzone.com/storage/article-thumb/10954057-thumb.jpg">
|
||
<meta property="og:type" content="article">
|
||
|
||
<meta name="twitter:site" content="@DZoneInc">
|
||
<meta name="twitter:image" content="https://dz2cdn1.dzone.com/storage/article-thumb/10954057-thumb.jpg">
|
||
<meta name="twitter:card" content="summary_large_image">
|
||
<meta name="twitter:description" content="An overview of how developers and data scientists can use various transaction models (exactly-once, at-least-once, etc.) out of the box with Apache Kafka.">
|
||
<meta name="twitter:title" content="Interpreting Kafka's Exactly-Once Semantics">
|
||
|
||
|
||
|
||
<meta name="referrer" content="origin-when-cross-origin">
|
||
<meta name="google-site-verification" content="kndbhxcupfEqWmZclhCpB6vlgOs7QSmx2UHAGGnP2mA">
|
||
<meta name="df-verify" content="df0d76632b4543">
|
||
|
||
<link rel="icon" type="image/x-icon" href="https://dz2cdn1.dzone.com/themes/dz20/images/favicon.png">
|
||
<link rel="image_src" href="https://dz2cdn1.dzone.com/storage/article-thumb/10954057-thumb.jpg">
|
||
<link rel="canonical" href="https://dzone.com/articles/interpreting-kafkas-exactly-once-semantics">
|
||
|
||
<title>Interpreting Kafka's Exactly-Once Semantics</title>
|
||
|
||
<link rel="preload" href="https://dz2cdn1.dzone.com/themes/dz20/font/fontello.woff?11773374" as="font" type="font/woff" crossorigin="anonymous">
|
||
|
||
<link rel="stylesheet" media="all" href="https://dz2cdn1.dzone.com/themes/dz20/ftl/icons.css">
|
||
<link rel="stylesheet" media="all" href="https://dz2cdn1.dzone.com/themes/dz20/lib/static/bootstrap/bootstrap.min.css">
|
||
<link rel="stylesheet" media="all" href="https://dz2cdn1.dzone.com/themes/dz20/ftl/article/global.css">
|
||
<link rel="stylesheet" media="all" href="https://dz2cdn1.dzone.com/themes/dz20/ftl/header-updated/styles.css">
|
||
<style>
|
||
:root {
|
||
--xs-size: 2px;
|
||
--sm-size: 5px;
|
||
--md-size: 10px;
|
||
--lg-size: 15px;
|
||
--xl-size: 25px;
|
||
--sm-border-size: 8px;
|
||
--sm-font-size: 13px;
|
||
--sm-plus-font-size: 16px;
|
||
--md-font-size: 18px;
|
||
--lg-font-size: 22px;
|
||
--xl-font-size: 26px;
|
||
}
|
||
|
||
/* Display Quick-Access Classes */
|
||
.display-none { display: none; }
|
||
.display-block { display: block; }
|
||
.display-inline { display: inline; }
|
||
.display-inline-block { display: inline-block; }
|
||
|
||
/* Margin Quick-Access Classes */
|
||
.m-xs { margin: var(--xs-size); }
|
||
.m-sm { margin: var(--sm-size); }
|
||
.m-md { margin: var(--md-size); }
|
||
.m-lg { margin: var(--lg-size); }
|
||
.m-xl { margin: var(--xl-size); }
|
||
|
||
.mt-xs, .my-xs { margin-top: var(--xs-size); }
|
||
.mr-xs, .mx-xs { margin-right: var(--xs-size); }
|
||
.mb-xs, .my-xs { margin-bottom: var(--xs-size); }
|
||
.ml-xs, .mx-xs { margin-left: var(--xs-size); }
|
||
|
||
.mt-sm, .my-sm { margin-top: var(--sm-size); }
|
||
.mr-sm, .mx-sm { margin-right: var(--sm-size); }
|
||
.mb-sm, .my-sm { margin-bottom: var(--sm-size); }
|
||
.ml-sm, .mx-sm { margin-left: var(--sm-size); }
|
||
|
||
.mt-md, .my-md { margin-top: var(--md-size); }
|
||
.mr-md, .mx-md { margin-right: var(--md-size); }
|
||
.mb-md, .my-md { margin-bottom: var(--md-size); }
|
||
.ml-md, .mx-md { margin-left: var(--md-size); }
|
||
|
||
.mt-lg, .my-lg { margin-top: var(--lg-size); }
|
||
.mr-lg, .mx-lg { margin-right: var(--lg-size); }
|
||
.mb-lg, .my-lg { margin-bottom: var(--lg-size); }
|
||
.ml-lg, .mx-lg { margin-left: var(--lg-size); }
|
||
|
||
.mt-xl, .my-xl { margin-top: var(--xl-size); }
|
||
.mr-xl, .mx-xl { margin-right: var(--xl-size); }
|
||
.mb-xl, .my-xl { margin-bottom: var(--xl-size); }
|
||
.ml-xl, .mx-xl { margin-left: var(--xl-size); }
|
||
|
||
.ml-auto, .mx-auto { margin-left: auto; }
|
||
.mr-auto, .mx-auto { margin-right: auto; }
|
||
.mt-auto, .my-auto { margin-top: auto; }
|
||
.mb-auto, .my-auto { margin-bottom: auto; }
|
||
|
||
.my-none, .mt-none { margin-top: 0 !important; }
|
||
.mx-none, .mr-none { margin-right: 0 !important; }
|
||
.my-none, .mb-none { margin-bottom: 0 !important; }
|
||
.mx-none, .ml-none { margin-left: 0 !important; }
|
||
|
||
/* Padding Quick-Access Classes */
|
||
.p-xs { padding: var(--xs-size); }
|
||
.p-sm { padding: var(--sm-size); }
|
||
.p-md { padding: var(--md-size); }
|
||
.p-lg { padding: var(--lg-size); }
|
||
.p-xl { padding: var(--xl-size); }
|
||
|
||
.pt-xs, .py-xs { padding-top: var(--xs-size); }
|
||
.pr-xs, .px-xs { padding-right: var(--xs-size); }
|
||
.pb-xs, .py-xs { padding-bottom: var(--xs-size); }
|
||
.pl-xs, .px-xs { padding-left: var(--xs-size); }
|
||
|
||
.pt-sm, .py-sm { padding-top: var(--sm-size); }
|
||
.pr-sm, .px-sm { padding-right: var(--sm-size); }
|
||
.pb-sm, .py-sm { padding-bottom: var(--sm-size); }
|
||
.pl-sm, .px-sm { padding-left: var(--sm-size); }
|
||
|
||
.pt-md, .py-md { padding-top: var(--md-size); }
|
||
.pr-md, .px-md { padding-right: var(--md-size); }
|
||
.pb-md, .py-md { padding-bottom: var(--md-size); }
|
||
.pl-md, .px-md { padding-left: var(--md-size); }
|
||
|
||
.pt-lg, .py-lg { padding-top: var(--lg-size); }
|
||
.pr-lg, .px-lg { padding-right: var(--lg-size); }
|
||
.pb-lg, .py-lg { padding-bottom: var(--lg-size); }
|
||
.pl-lg, .px-lg { padding-left: var(--lg-size); }
|
||
|
||
.pt-xl, .py-xl { padding-top: var(--xl-size); }
|
||
.pr-xl, .px-xl { padding-right: var(--xl-size); }
|
||
.pb-xl, .py-xl { padding-bottom: var(--xl-size); }
|
||
.pl-xl, .px-xl { padding-left: var(--xl-size); }
|
||
|
||
.py-none, .pt-none { padding-top: 0 !important; }
|
||
.px-none, .pr-none { padding-right: 0 !important; }
|
||
.py-none, .pb-none { padding-bottom: 0 !important; }
|
||
.px-none, .pl-none { padding-left: 0 !important; }
|
||
|
||
/* Flex Quick-Access Classes */
|
||
.flex {
|
||
display: flex;
|
||
}
|
||
|
||
.flex-column {
|
||
display: flex;
|
||
flex-direction: column;
|
||
}
|
||
|
||
.flex-column-reverse {
|
||
display: flex;
|
||
flex-direction: column-reverse;
|
||
}
|
||
|
||
.flex-row {
|
||
display: flex;
|
||
flex-direction: row;
|
||
}
|
||
|
||
.flex-row-reverse {
|
||
display: flex;
|
||
flex-direction: row-reverse;
|
||
}
|
||
|
||
.flex-wrap {
|
||
flex-wrap: wrap;
|
||
}
|
||
|
||
.flex-grow {
|
||
flex-grow: 1;
|
||
}
|
||
|
||
.align-center { align-items: center; }
|
||
.align-end { align-items: flex-end; }
|
||
|
||
.content-center {
|
||
align-content: center;
|
||
}
|
||
|
||
.justify-center { justify-content: center; }
|
||
.justify-start { justify-content: flex-start; }
|
||
.justify-end { justify-content: flex-end; }
|
||
.justify-around { justify-content: space-around; }
|
||
.justify-between { justify-content: space-between; }
|
||
.justify-evenly { justify-content: space-evenly; }
|
||
|
||
.gap-sm { gap: var(--sm-size); }
|
||
.gap-md { gap: var(--md-size); }
|
||
.gap-lg { gap: var(--lg-size); }
|
||
.gap-xl { gap: var(--xl-size); }
|
||
|
||
/* Display Quick-Access Classes */
|
||
.inline-block { display: inline-block; }
|
||
|
||
/* Font Quick-Access Classes */
|
||
.font-xl { font-size: var(--xl-font-size); }
|
||
.font-lg { font-size: var(--lg-font-size); }
|
||
.font-md { font-size: var(--md-font-size); }
|
||
.font-sm-plus { font-size: var(--sm-plus-font-size); }
|
||
.font-sm { font-size: var(--sm-font-size); }
|
||
|
||
.font-strike { text-decoration: line-through; }
|
||
.font-underline { text-decoration: underline; }
|
||
.font-overline { text-decoration: overline; }
|
||
|
||
.font-italic { font-style: italic; }
|
||
.font-bold { font-weight: bold; }
|
||
|
||
.font-black { color: #000000; }
|
||
.font-white { color: #ffffff; }
|
||
.font-gray { color: var(--brand-gray-text); }
|
||
.font-danger { color: var(--header-dropdown-button-bg-danger); }
|
||
.font-center { text-align: center; }
|
||
|
||
.no-wrap { white-space: nowrap; }
|
||
|
||
/* Consistent headings between h and non-h tags */
|
||
.heading {
|
||
margin-top: 0;
|
||
margin-bottom: var(--md-size);
|
||
}
|
||
|
||
.heading.font-xl { line-height: var(--xl-font-size); }
|
||
.heading.font-lg { line-height: var(--lg-font-size); }
|
||
.heading.font-md { line-height: var(--md-font-size); }
|
||
.heading.font-sm-plus { line-height: var(--sm-plus-font-size); }
|
||
.heading.font-sm { line-height: var(--sm-font-size); }
|
||
|
||
/* Font Clamp Quick-Access Classes */
|
||
.line-clamp,
|
||
.line-clamp-2,
|
||
.line-clamp-3,
|
||
.line-clamp-4,
|
||
.line-clamp-5 {
|
||
display: -webkit-box;
|
||
-webkit-line-clamp: 4;
|
||
-webkit-box-orient: vertical;
|
||
overflow: hidden;
|
||
text-overflow: ellipsis;
|
||
}
|
||
|
||
.line-clamp-2 { -webkit-line-clamp: 2 !important; }
|
||
.line-clamp-3 { -webkit-line-clamp: 3 !important; }
|
||
.line-clamp-4 { -webkit-line-clamp: 4 !important; }
|
||
.line-clamp-5 { -webkit-line-clamp: 5 !important; }
|
||
|
||
/* User-Select Quick-Access Classes */
|
||
.select-none { user-select: none; }
|
||
|
||
/* Position Quick-Access Classes */
|
||
.absolute { position: absolute; }
|
||
.relative { position: relative; }
|
||
.float-left { float: left; }
|
||
.float-right { float: right; }
|
||
|
||
.pos-top { top: 0; }
|
||
.pos-right { right: 0; }
|
||
.pos-bottom { bottom: 0; }
|
||
.pos-left { left: 0; }
|
||
|
||
.va-top { vertical-align: top; }
|
||
.va-middle { vertical-align: middle; }
|
||
.va-bottom { vertical-align: bottom; }
|
||
|
||
/* Transition Quick-Access Classes */
|
||
.trans-linear-quick {
|
||
transition: all 0.15s linear;
|
||
}
|
||
|
||
/* Background Quick-Access Classes */
|
||
.bg-gray { background: #cccccc; }
|
||
.bg-white { background-color: white; }
|
||
.bg-none { background: none; }
|
||
|
||
/* Border Quick-Access Classes */
|
||
.border-gray { border: 1px solid #cccccc; }
|
||
.tab-pane.border-gray { border: 1px solid #ddd; }
|
||
.no-border, .border-none { border: none !important; }
|
||
|
||
.bt-none { border-top: none !important; }
|
||
.br-none { border-right: none !important; }
|
||
.bb-none { border-bottom: none !important; }
|
||
.bl-none { border-left: none !important; }
|
||
|
||
/* Border Radius Quick-Access Classes */
|
||
|
||
.round-t-sm, .round-tl-sm { border-top-left-radius: var(--sm-border-size); }
|
||
.round-t-sm, .round-tr-sm { border-top-right-radius: var(--sm-border-size); }
|
||
.round-b-sm, .round-bl-sm { border-bottom-left-radius: var(--sm-border-size); }
|
||
.round-b-sm, .round-br-sm { border-bottom-right-radius: var(--sm-border-size); }
|
||
.round-sm { border-radius: var(--sm-border-size); }
|
||
.round-fully { border-radius: 50%; }
|
||
|
||
/* Misc Quick-Access Classes */
|
||
.haikei {
|
||
position: relative;
|
||
background-image: url('https://dz2cdn1.dzone.com/themes/dz20/images/polygon-scatter-haikei-shapes.svg');
|
||
background-repeat: no-repeat;
|
||
background-size: cover;
|
||
}
|
||
|
||
.haikei:before {
|
||
content: '';
|
||
position:absolute;
|
||
top: 0;
|
||
left: 0;
|
||
width: 100%;
|
||
height: 100%;
|
||
background-color: var(--color-event-background);
|
||
z-index: -1;
|
||
}
|
||
|
||
.margin-auto-center {
|
||
display: block;
|
||
margin-left: auto;
|
||
margin-right: auto;
|
||
}
|
||
|
||
.flex-auto-center {
|
||
display: flex;
|
||
margin-left: auto;
|
||
margin-right: auto;
|
||
}
|
||
|
||
.mw-1100 { max-width: 1100px; }
|
||
.mw-1300 { max-width: 1300px; }
|
||
.full-width { width: 100%; }
|
||
|
||
.h-separator {
|
||
background-color: #cccccc;
|
||
height: 1px;
|
||
width: 100%;
|
||
margin: 5px auto;
|
||
}
|
||
|
||
.no-spacing {
|
||
margin: 0 !important;
|
||
padding: 0 !important;
|
||
}
|
||
|
||
.inherit-color { color: inherit; }
|
||
|
||
.inherit-decoration { text-decoration: inherit; }
|
||
|
||
/* Table Quick-Access Classes */
|
||
.table-border-gray tr:not(:last-child) {
|
||
border-bottom: 1px solid #cccccc;
|
||
}
|
||
|
||
table.full-width tr td:last-child {
|
||
width:100%;
|
||
}
|
||
|
||
/* Animation Quick-Access Classes */
|
||
@keyframes anim-spin {
|
||
0% { transform: rotate(0deg); }
|
||
100% { transform: rotate(359deg); }
|
||
}
|
||
|
||
.anim-spin {
|
||
display: inline-block;
|
||
animation: anim-spin 2s infinite linear;
|
||
}
|
||
|
||
.hov-pointer { cursor: pointer; }
|
||
.hov-brighten:hover { filter: brightness(1.2); }
|
||
.hov-darken:hover { filter: brightness(0.95); }
|
||
.hov-underline:hover { text-decoration: underline; }
|
||
|
||
/* Small tweaks related to components when using these styles */
|
||
.nav-tabs {
|
||
border-bottom: none;
|
||
}
|
||
.tab-content > .flex-column.active,
|
||
.tab-content > .flex-row.active {
|
||
display: flex;
|
||
}
|
||
|
||
/* Alpine components with x-cloak should not be visible by default until conditionals kick in */
|
||
[x-cloak] { display: none !important; }
|
||
</style>
|
||
<link rel="stylesheet" media="all" href="https://dz2cdn1.dzone.com/themes/dz20/ftl/alpine-components/modal.css">
|
||
<script defer src="https://dz2cdn1.dzone.com/themes/dz20/lib/alpinejs/3.13.2/cdn.min.js"></script>
|
||
<script>
|
||
document.addEventListener('alpine:init', () => {
|
||
Alpine.store('article', {
|
||
id: null,
|
||
engagement: {
|
||
open: false,
|
||
page: 1,
|
||
users: [],
|
||
additional: true,
|
||
loading: false,
|
||
initializing: false,
|
||
unauthorized: false,
|
||
enqueued: null,
|
||
dequeued: null,
|
||
|
||
reset() {
|
||
this.open = false;
|
||
this.page = 1;
|
||
this.users.splice(0);
|
||
this.additional = true;
|
||
this.loading = false;
|
||
this.initializing = false;
|
||
this.enqueued = null;
|
||
this.dequeued = null;
|
||
},
|
||
|
||
enqueue(user) {
|
||
this.dequeued = null;
|
||
this.enqueued = user;
|
||
},
|
||
|
||
dequeue(user) {
|
||
this.enqueued = null;
|
||
this.dequeued = user;
|
||
},
|
||
|
||
add(user) {
|
||
this.users.push(user);
|
||
this.enqueued = null;
|
||
},
|
||
|
||
remove(user) {
|
||
const index = this.users.findIndex(u => u.id === user.id);
|
||
|
||
if (index !== -1) {
|
||
this.users.splice(index, 1);
|
||
}
|
||
|
||
this.dequeued = null;
|
||
},
|
||
|
||
contains(user) {
|
||
return this.users.filter(u => u.id === user.id).length;
|
||
}
|
||
}
|
||
});
|
||
|
||
Alpine.effect(() => {
|
||
const store = Alpine.store('article');
|
||
if (!store.engagement.additional && store.engagement.enqueued) {
|
||
if (!store.engagement.contains(store.engagement.enqueued)) {
|
||
store.engagement.add(store.engagement.enqueued);
|
||
}
|
||
}
|
||
});
|
||
|
||
Alpine.effect(() => {
|
||
const store = Alpine.store('article');
|
||
if (store.engagement.page && store.engagement.dequeued) {
|
||
store.engagement.remove(store.engagement.dequeued);
|
||
}
|
||
})
|
||
});
|
||
</script></head>
|
||
<body x-data>
|
||
<div class="skybox skybox-closeBtn dz_skybox" data-gpt-slot="skybox" id="div-gpt-ad-1435246566686-99"></div>
|
||
<header id="ftl-header">
|
||
<div class="header-top">
|
||
<div class="header-container">
|
||
<div class="pull-left logo-container">
|
||
<div class="logo">
|
||
<a class="inner" href="/">
|
||
<picture>
|
||
<source srcset="https://dz2cdn1.dzone.com/themes/dz20/images/dz_logo_2021_cropped.webp" type="image/webp">
|
||
<source srcset="https://dz2cdn1.dzone.com/themes/dz20/images/dz_logo_2021_cropped.png" type="image/png">
|
||
<img src="https://dz2cdn1.dzone.com/themes/dz20/images/dz_logo_2021_cropped.png" width="181" height="56" alt="DZone">
|
||
</picture>
|
||
</a>
|
||
</div>
|
||
</div>
|
||
|
||
<div class="pull-right login-and-search">
|
||
<div id="authenticated-block" class="logged-in">
|
||
<div class="welcome-back">Thanks for visiting DZone today,</div>
|
||
<div id="user-header" class="user-info">
|
||
<button class="user-avatar">
|
||
<span id="header-username" class="username"></span>
|
||
<img id="header-avatar" src="" alt="user avatar">
|
||
</button>
|
||
<div id="user-dropdown" class="browse-user-menu">
|
||
<div class="user-content">
|
||
<a id="header-user-plug" href="#" class="user-description"></a>
|
||
<a id="header-user-edit" href="#" class="edit-profile">Edit Profile</a>
|
||
</div>
|
||
<ul class="user-actions">
|
||
<li id="first-user-action">
|
||
<a id="header-dropdown-manage-email" href="#">Manage Email Subscriptions</a>
|
||
</li>
|
||
<li>
|
||
<a href="/articles/how-to-submit-a-post-to-dzone?utm_source=DZone&utm_medium=user_dropdown&utm_campaign=how_to_post">
|
||
How to Post to DZone
|
||
</a>
|
||
</li>
|
||
<li>
|
||
<a href="/articles/dzones-article-submission-guidelines">
|
||
Article Submission Guidelines
|
||
</a>
|
||
</li>
|
||
</ul>
|
||
<div class="bottom">
|
||
<a href="/users/logout.html" class="sign-out">Sign Out</a>
|
||
<a id="dropdown-view-profile" href="#" class="view-profile">View Profile</a>
|
||
</div>
|
||
</div>
|
||
</div>
|
||
|
||
<div class="post-content">
|
||
<button id="post-button" class="post-content--button">
|
||
<span class="post-class">Post</span>
|
||
<i class="icon-plus"></i>
|
||
</button>
|
||
|
||
<div id="post-menu" class="posting-links">
|
||
<div class="posting-links-menu">
|
||
<ul>
|
||
<li>
|
||
<img src="https://dz2cdn1.dzone.com/themes/dz20/images/dz-postarticle.svg" width="15" height="18" style="width: 15px; height: 18px;">
|
||
<a href="/content/article/post.html">Post an Article</a>
|
||
</li>
|
||
<li>
|
||
<a id="drafts-link" href="#">Manage My Drafts</a>
|
||
</li>
|
||
</ul>
|
||
</div>
|
||
</div>
|
||
</div>
|
||
</div>
|
||
|
||
<div id="unauthenticated-block">
|
||
<div class="dz-intro">Over 2 million developers have joined DZone.</div>
|
||
<div class="mobile-invisible sign-in-join">
|
||
<a href="/users/login.html">Log In</a>
|
||
<span class="dz-intro-span">/</span>
|
||
<a href="/static/registration.html">Join</a>
|
||
</div>
|
||
<a class="join-icon" href="/users/login.html" aria-label="User">
|
||
<svg xmlns="http://www.w3.org/2000/svg" width="24" height="24" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round" class="lucide svg-user lucide-user-icon lucide-user">
|
||
<path d="M19 21v-2a4 4 0 0 0-4-4H9a4 4 0 0 0-4 4v2"></path>
|
||
<circle cx="12" cy="7" r="4"></circle>
|
||
</svg>
|
||
</a>
|
||
</div>
|
||
|
||
<script>
|
||
document.addEventListener('alpine:init', () => {
|
||
Alpine.data('searchDrawer', () => ({
|
||
open: false,
|
||
query: '',
|
||
minCharsMet: false,
|
||
|
||
toggleVisibility() {
|
||
this.open = !this.open;
|
||
if (this.open) {
|
||
this.$nextTick(() => {
|
||
this.$refs.query.focus();
|
||
});
|
||
}
|
||
},
|
||
|
||
updateSearchValue() {
|
||
if (!this.query || !this.query.length || this.query.length < 3) {
|
||
this.minCharsMet = false;
|
||
return;
|
||
}
|
||
this.minCharsMet = true;
|
||
localStorage.setItem('ls.searchValue', this.query);
|
||
},
|
||
|
||
searchSite() {
|
||
if (this.minCharsMet) {
|
||
window.location = '/search';
|
||
}
|
||
}
|
||
}));
|
||
});
|
||
</script>
|
||
|
||
<div class="headerSearch" x-data="searchDrawer()" x-cloak>
|
||
<button class="btn-search dropdown-toggle" x-on:click="toggleVisibility()" aria-label="Search">
|
||
<svg xmlns="http://www.w3.org/2000/svg" width="24" height="24" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round" class="lucide svg-search lucide-search-icon lucide-search">
|
||
<path d="m21 21-4.34-4.34"></path>
|
||
<circle cx="11" cy="11" r="8"></circle>
|
||
</svg>
|
||
</button>
|
||
<template x-teleport=".header-container">
|
||
<div id="search-drawer" x-show="open" x-on:click.outside="open = false" x-transition>
|
||
<div class="search-input">
|
||
<input type="text"
|
||
placeholder="Search"
|
||
autofocus="autofocus"
|
||
x-model="query"
|
||
x-ref="query"
|
||
x-on:input.change="updateSearchValue()"
|
||
x-on:keyup.enter="searchSite()"
|
||
>
|
||
<button x-on:click="searchSite()" x-bind:disabled="!minCharsMet">
|
||
<span>Search</span>
|
||
</button>
|
||
</div>
|
||
<div class="search-footer">
|
||
Please enter at least three characters to search
|
||
</div>
|
||
</div>
|
||
</template>
|
||
</div>
|
||
</div>
|
||
</div> </div>
|
||
<div class="header-bottom">
|
||
<div class="header-bottom-container">
|
||
<a class="resource-link" href="/refcardz">Refcards</a>
|
||
<a class="resource-link" href="/trendreports">Trend Reports</a>
|
||
<div class="resource-link link-menu">
|
||
<a href="/events">Events</a>
|
||
<a href="/events/video-library">Video Library</a>
|
||
</div>
|
||
</div>
|
||
</div>
|
||
<nav class="header-menu-bar">
|
||
<div class="header-menu resource-category">
|
||
<a href="/refcardz">Refcards</a>
|
||
</div>
|
||
<div class="header-menu-separator resource-category-separator"></div>
|
||
<div class="header-menu resource-category">
|
||
<a href="/trendreports">Trend Reports</a>
|
||
</div>
|
||
<div class="header-menu-separator resource-category-separator"></div>
|
||
<div class="header-menu resource-category no-bottom-radius" data-click-activation>
|
||
<p class="menu-label">Events</p>
|
||
<div class="header-menu-items">
|
||
<div class="header-menu-columns">
|
||
<a class="header-menu-item" href="/events">View Events</a>
|
||
<a class="header-menu-item" href="/events/video-library">Video Library</a>
|
||
</div>
|
||
</div>
|
||
</div>
|
||
<div class="header-menu zone-menu" data-click-activation>
|
||
<p class="menu-label">Zones <i class="icon-down-dir icon-closed"></i><i class="icon-right-dir icon-open"></i></p>
|
||
<div class="header-menu-items">
|
||
<div class="header-menu-columns">
|
||
<div class="header-menu-column-item">
|
||
<a class="header-menu-item" href="/culture-and-methodologies">Culture and Methodologies</a>
|
||
<a class="header-menu-item" href="/agile">Agile</a>
|
||
<a class="header-menu-item" href="/career-development">Career Development</a>
|
||
<a class="header-menu-item" href="/methodologies">Methodologies</a>
|
||
<a class="header-menu-item" href="/team-management">Team Management</a>
|
||
</div>
|
||
<div class="header-menu-column-item">
|
||
<a class="header-menu-item" href="/data-engineering">Data Engineering</a>
|
||
<a class="header-menu-item" href="/ai-ml">AI/ML</a>
|
||
<a class="header-menu-item" href="/big-data">Big Data</a>
|
||
<a class="header-menu-item" href="/data">Data</a>
|
||
<a class="header-menu-item" href="/databases">Databases</a>
|
||
<a class="header-menu-item" href="/iot">IoT</a>
|
||
</div>
|
||
<div class="header-menu-column-item">
|
||
<a class="header-menu-item" href="/software-design-and-architecture">Software Design and Architecture</a>
|
||
<a class="header-menu-item" href="/cloud-architecture">Cloud Architecture</a>
|
||
<a class="header-menu-item" href="/containers">Containers</a>
|
||
<a class="header-menu-item" href="/integration">Integration</a>
|
||
<a class="header-menu-item" href="/microservices">Microservices</a>
|
||
<a class="header-menu-item" href="/performance">Performance</a>
|
||
<a class="header-menu-item" href="/security">Security</a>
|
||
</div>
|
||
<div class="header-menu-column-item">
|
||
<a class="header-menu-item" href="/coding">Coding</a>
|
||
<a class="header-menu-item" href="/frameworks">Frameworks</a>
|
||
<a class="header-menu-item" href="/java">Java</a>
|
||
<a class="header-menu-item" href="/javascript">JavaScript</a>
|
||
<a class="header-menu-item" href="/languages">Languages</a>
|
||
<a class="header-menu-item" href="/tools">Tools</a>
|
||
</div>
|
||
<div class="header-menu-column-item">
|
||
<a class="header-menu-item" href="/testing-deployment-and-maintenance">Testing, Deployment, and Maintenance</a>
|
||
<a class="header-menu-item" href="/deployment">Deployment</a>
|
||
<a class="header-menu-item" href="/devops-and-cicd">DevOps and CI/CD</a>
|
||
<a class="header-menu-item" href="/maintenance">Maintenance</a>
|
||
<a class="header-menu-item" href="/monitoring-and-observability">Monitoring and Observability</a>
|
||
<a class="header-menu-item" href="/testing-tools-and-frameworks">Testing, Tools, and Frameworks</a>
|
||
</div>
|
||
<div class="header-menu-column-item sponsored">
|
||
<a class="header-menu-item" href="javascript:void(0)">Partner Zones</a>
|
||
<a class="header-menu-item" href="/hubs/build-ai-agents-that-are-ready-for-production/">Build AI Agents That Are Ready for Production</a>
|
||
</div>
|
||
</div>
|
||
</div>
|
||
</div>
|
||
<div class="header-menu parent-category" tabindex="1">
|
||
<a href="/culture-and-methodologies">Culture and Methodologies</a>
|
||
<div class="header-menu-items">
|
||
<a class="header-menu-item" href="/agile">Agile</a>
|
||
<a class="header-menu-item" href="/career-development">Career Development</a>
|
||
<a class="header-menu-item" href="/methodologies">Methodologies</a>
|
||
<a class="header-menu-item" href="/team-management">Team Management</a>
|
||
</div>
|
||
</div>
|
||
<div class="header-menu-separator parent-category-separator"></div>
|
||
<div class="header-menu parent-category" tabindex="2">
|
||
<a href="/data-engineering">Data Engineering</a>
|
||
<div class="header-menu-items">
|
||
<a class="header-menu-item" href="/ai-ml">AI/ML</a>
|
||
<a class="header-menu-item" href="/big-data">Big Data</a>
|
||
<a class="header-menu-item" href="/data">Data</a>
|
||
<a class="header-menu-item" href="/databases">Databases</a>
|
||
<a class="header-menu-item" href="/iot">IoT</a>
|
||
</div>
|
||
</div>
|
||
<div class="header-menu-separator parent-category-separator"></div>
|
||
<div class="header-menu parent-category" tabindex="3">
|
||
<a href="/software-design-and-architecture">Software Design and Architecture</a>
|
||
<div class="header-menu-items">
|
||
<a class="header-menu-item" href="/cloud-architecture">Cloud Architecture</a>
|
||
<a class="header-menu-item" href="/containers">Containers</a>
|
||
<a class="header-menu-item" href="/integration">Integration</a>
|
||
<a class="header-menu-item" href="/microservices">Microservices</a>
|
||
<a class="header-menu-item" href="/performance">Performance</a>
|
||
<a class="header-menu-item" href="/security">Security</a>
|
||
</div>
|
||
</div>
|
||
<div class="header-menu-separator parent-category-separator"></div>
|
||
<div class="header-menu parent-category" tabindex="4">
|
||
<a href="/coding">Coding</a>
|
||
<div class="header-menu-items">
|
||
<a class="header-menu-item" href="/frameworks">Frameworks</a>
|
||
<a class="header-menu-item" href="/java">Java</a>
|
||
<a class="header-menu-item" href="/javascript">JavaScript</a>
|
||
<a class="header-menu-item" href="/languages">Languages</a>
|
||
<a class="header-menu-item" href="/tools">Tools</a>
|
||
</div>
|
||
</div>
|
||
<div class="header-menu-separator parent-category-separator"></div>
|
||
<div class="header-menu parent-category" tabindex="5">
|
||
<a href="/testing-deployment-and-maintenance">Testing, Deployment, and Maintenance</a>
|
||
<div class="header-menu-items">
|
||
<a class="header-menu-item" href="/deployment">Deployment</a>
|
||
<a class="header-menu-item" href="/devops-and-cicd">DevOps and CI/CD</a>
|
||
<a class="header-menu-item" href="/maintenance">Maintenance</a>
|
||
<a class="header-menu-item" href="/monitoring-and-observability">Monitoring and Observability</a>
|
||
<a class="header-menu-item" href="/testing-tools-and-frameworks">Testing, Tools, and Frameworks</a>
|
||
</div>
|
||
</div>
|
||
<div class="header-menu-separator parent-category-separator"></div>
|
||
<div class="header-menu parent-category sponsored" tabindex="6">
|
||
<a href="javascript:void(0)">Partner Zones</a>
|
||
<div class="header-menu-items sponsored">
|
||
<a class="header-menu-item" href="/hubs/build-ai-agents-that-are-ready-for-production/">Build AI Agents That Are Ready for Production</a>
|
||
</div>
|
||
</div>
|
||
<div class="header-menu-separator parent-category-separator"></div>
|
||
</nav>
|
||
</header>
|
||
|
||
<script>
|
||
const csrf = {
|
||
parameter: 'TH_CSRF',
|
||
header: 'X-TH-CSRF',
|
||
token: '-6473215330233261330'
|
||
}; // set csrf for auth-status script
|
||
</script>
|
||
<script>
|
||
addEventListener('DOMContentLoaded', function() {
|
||
handleRedirects();
|
||
handleMenus();
|
||
handleMobileMenuHeights();
|
||
handleGotoLinks();
|
||
});
|
||
|
||
function isHidden(element) {
|
||
try {
|
||
return window.getComputedStyle(element).display === 'none';
|
||
} catch (_) {
|
||
return false;
|
||
}
|
||
}
|
||
|
||
function getLink(element) {
|
||
if (element.hasAttribute('data-goto')) {
|
||
return element.getAttribute('data-goto');
|
||
}
|
||
return element.href;
|
||
}
|
||
|
||
function isLeftClick(event) {
|
||
if (event.altKey || event.shiftKey) {
|
||
return false;
|
||
} else if ('buttons' in event || 'which' in event) {
|
||
return event.buttons === 1 || event.which === 1;
|
||
} else {
|
||
return (event.button === 1 || (event.type === 'click'));
|
||
}
|
||
}
|
||
|
||
function handleRedirects() {
|
||
const redirections = [...document.querySelectorAll('[data-activate-menu]'), ...document.querySelectorAll('[data-click-target]')];
|
||
|
||
redirections.forEach(function(element) {
|
||
const menuSelector = element.getAttribute('data-activate-menu') || element.getAttribute('data-click-target');
|
||
const redirectingElement = document.querySelector(menuSelector);
|
||
if (redirectingElement) {
|
||
element.style.cursor = 'pointer';
|
||
const redirect = function(e) {
|
||
if (redirectingElement.hasAttribute('href') || redirectingElement.hasAttribute('data-goto')) {
|
||
if (redirectingElement.hasAttribute('data-new-window') || e.ctrlKey || e.metaKey) {
|
||
window.open(getLink(redirectingElement), '_blank');
|
||
} else {
|
||
window.open(getLink(redirectingElement), '_self');
|
||
}
|
||
} else {
|
||
const evt = new e.constructor(e.type, e);
|
||
redirectingElement.dispatchEvent(evt);
|
||
}
|
||
};
|
||
element.addEventListener('mouseup', redirect);
|
||
element.addEventListener('mousedown', (e) => e.preventDefault());
|
||
element.addEventListener('click', (e) => e.preventDefault());
|
||
}
|
||
});
|
||
}
|
||
|
||
function handleMenus() {
|
||
const menuElements = [
|
||
...document.querySelectorAll('.header-menu > a'),
|
||
...document.querySelectorAll('.header-menu > p.menu-label')
|
||
];
|
||
|
||
let scrollYMemory = -1;
|
||
|
||
function scrollToMemory() {
|
||
if (scrollYMemory !== -1) {
|
||
setTimeout(function() {
|
||
window.scrollTo(0, scrollYMemory);
|
||
scrollYMemory = -1;
|
||
}, 10);
|
||
}
|
||
}
|
||
|
||
function hideMenus() {
|
||
// unfocus menus & items, and set the menus to non-visible.
|
||
menuElements.forEach(function (element) {
|
||
element.blur();
|
||
element.parentElement.blur();
|
||
element.parentElement.classList.remove('menu-opened');
|
||
const menuItems = element.parentElement.querySelector('.header-menu-items');
|
||
if (menuItems) {
|
||
menuItems.style.display = 'none';
|
||
}
|
||
});
|
||
const wasHidden = document.body.style.overflowY === 'hidden';
|
||
document.body.style.overflowY = 'auto';
|
||
if (wasHidden) {
|
||
scrollToMemory();
|
||
}
|
||
}
|
||
|
||
function isEventOutsideMenu(e) {
|
||
return e.target.closest && !e.target.closest('.header-menu') && !e.target.closest('[data-activate-menu]');
|
||
}
|
||
|
||
// Handle mobile menu toggling
|
||
menuElements.forEach(function(element) {
|
||
const menu = element.parentElement;
|
||
const headerItems = menu.querySelector('.header-menu-items');
|
||
const menuEntries = headerItems ? headerItems.querySelectorAll('.header-menu-item') : [];
|
||
|
||
const focus = function() {
|
||
menu.focus();
|
||
menu.classList.add('menu-opened');
|
||
if (headerItems) {
|
||
headerItems.style.display = 'block';
|
||
}
|
||
if (menu.classList.contains('zone-menu')) {
|
||
scrollYMemory = window.scrollY;
|
||
document.body.style.overflowY = 'hidden';
|
||
} else {
|
||
scrollYMemory = -1;
|
||
}
|
||
};
|
||
|
||
const unfocus = function() {
|
||
menu.blur();
|
||
menu.classList.remove('menu-opened');
|
||
if (headerItems) {
|
||
headerItems.style.display = 'none';
|
||
}
|
||
const wasHidden = document.body.style.overflowY === 'hidden';
|
||
document.body.style.overflowY = 'auto';
|
||
if (wasHidden) {
|
||
scrollToMemory();
|
||
}
|
||
};
|
||
|
||
const toggleMenuVisibility = function(e) {
|
||
if ((e.type === 'click' || e.type === 'mouseup') && !isLeftClick(e)) {
|
||
e.preventDefault();
|
||
return;
|
||
}
|
||
const hidden = isHidden(headerItems);
|
||
if (menu.hasAttribute('data-click-activation')) { // handle click activated toggling
|
||
if (hidden) {
|
||
hideMenus(); // hide other open menus first
|
||
focus();
|
||
} else {
|
||
unfocus();
|
||
}
|
||
e.preventDefault();
|
||
} else if (hidden) {
|
||
hideMenus(); // hide other open menus first
|
||
focus();
|
||
e.preventDefault(); // prevent 'click' event from firing when menu is hidden
|
||
}
|
||
};
|
||
|
||
element.addEventListener('touchend', toggleMenuVisibility);
|
||
element.addEventListener('mouseup', toggleMenuVisibility);
|
||
|
||
// Add hover events to non-click-activated menus, even though CSS should cover it.
|
||
if (!menu.hasAttribute('data-click-activation')) {
|
||
menu.addEventListener('mouseover', function () {
|
||
hideMenus(); // hide other open menus first
|
||
focus();
|
||
});
|
||
|
||
menu.addEventListener('mouseout', function (e) {
|
||
if (isEventOutsideMenu(e)) {
|
||
unfocus();
|
||
}
|
||
});
|
||
}
|
||
|
||
// Hide menu when child is clicked
|
||
menuEntries.forEach(function(menuEntry) {
|
||
const linkToItem = function(e) {
|
||
if (e.type === 'mousedown' || e.type === 'click') {
|
||
e.preventDefault();
|
||
return;
|
||
}
|
||
if (e.type === 'mouseup' && !isLeftClick(e)) {
|
||
e.preventDefault();
|
||
return;
|
||
}
|
||
window.open(getLink(menuEntry), (e.ctrlKey || e.metaKey) ? '_blank' : (menuEntry.target || '_self'));
|
||
unfocus();
|
||
e.preventDefault();
|
||
};
|
||
|
||
const linkToMobileItem = function(e) {
|
||
if (e.type === 'touchstart') {
|
||
menuEntry.setAttribute('data-touchmove', false);
|
||
} else if (e.type === 'touchmove') {
|
||
menuEntry.setAttribute('data-touchmove', true);
|
||
} else if (e.type === 'touchend' && (!menuEntry.hasAttribute('data-touchmove') || menuEntry.getAttribute('data-touchmove').toLowerCase() === 'false')) {
|
||
window.open(getLink(menuEntry), (e.ctrlKey || e.metaKey) ? '_blank' : (menuEntry.target || '_self'));
|
||
unfocus();
|
||
e.preventDefault();
|
||
}
|
||
};
|
||
|
||
menuEntry.addEventListener('mousedown', linkToItem);
|
||
menuEntry.addEventListener('mouseup', linkToItem);
|
||
menuEntry.addEventListener('click', linkToItem);
|
||
menuEntry.addEventListener('touchstart', linkToMobileItem);
|
||
menuEntry.addEventListener('touchmove', linkToMobileItem);
|
||
menuEntry.addEventListener('touchend', linkToMobileItem);
|
||
});
|
||
});
|
||
|
||
function hideIfNonMenuBounds(e) {
|
||
if (isEventOutsideMenu(e)) {
|
||
hideMenus();
|
||
}
|
||
}
|
||
|
||
addEventListener('mousemove', hideIfNonMenuBounds);
|
||
addEventListener('touchend', hideIfNonMenuBounds);
|
||
addEventListener('mouseup', hideIfNonMenuBounds);
|
||
addEventListener('mousedown', hideIfNonMenuBounds);
|
||
addEventListener('click', hideIfNonMenuBounds);
|
||
}
|
||
|
||
function handleMobileMenuHeights() {
|
||
function setAppHeight() {
|
||
document.documentElement.style.setProperty('--app-height', window.innerHeight + 'px');
|
||
}
|
||
|
||
addEventListener('resize', function() {
|
||
setAppHeight();
|
||
});
|
||
|
||
setAppHeight();
|
||
}
|
||
|
||
function handleGotoLinks() {
|
||
// Add anchor mimicking to elements with data-goto attributes
|
||
// This addresses SEO concerns of linking to noindex pages by allowing JS to handle the URL
|
||
const anchorElements = document.querySelectorAll('*[data-goto]');
|
||
anchorElements.forEach((anchorElement) => {
|
||
anchorElement.addEventListener('mouseover', () => {
|
||
anchorElement.style.cursor = 'pointer';
|
||
anchorElement.style.textDecoration = 'underline';
|
||
});
|
||
anchorElement.addEventListener('mouseout', () => {
|
||
anchorElement.style.cursor = 'unset';
|
||
anchorElement.style.textDecoration = 'unset';
|
||
});
|
||
anchorElement.addEventListener('mouseup', (e) => {
|
||
e.preventDefault();
|
||
});
|
||
anchorElement.addEventListener('mousedown', (e) => {
|
||
e.preventDefault();
|
||
});
|
||
anchorElement.addEventListener('click', (e) => {
|
||
e.preventDefault();
|
||
const anchorHref = anchorElement.getAttribute('data-goto');
|
||
if (anchorElement.hasAttribute('data-new-window') || e.ctrlKey || e.metaKey) {
|
||
window.open(anchorHref, '_blank');
|
||
} else {
|
||
window.open(anchorHref, '_self');
|
||
}
|
||
});
|
||
});
|
||
}
|
||
</script><script>
|
||
const authenticatedBlock = document.querySelector('#authenticated-block');
|
||
const unauthenticatedBlock = document.querySelector('#unauthenticated-block');
|
||
|
||
let authenticated = {
|
||
isAuthenticated: false,
|
||
isAdmin: false,
|
||
user: {
|
||
id: null,
|
||
name: null,
|
||
url: null,
|
||
profileImage: null,
|
||
}
|
||
};
|
||
|
||
fetch('/services/internal/data/articles-getAuthenticationStatus', {
|
||
headers: {
|
||
'Accept': 'application/json'
|
||
}
|
||
})
|
||
.then(function (result) {
|
||
return result.json()
|
||
})
|
||
.then(function (result) {
|
||
const res = result.result.data
|
||
if (!res.authenticated) {
|
||
unauthenticatedBlock.classList.add('shown')
|
||
} else {
|
||
authenticated.user.id = res.id;
|
||
authenticated.user.name = res.realName;
|
||
authenticated.user.url = res.profileUrl;
|
||
authenticated.user.profileImage = res.avatar;
|
||
authenticated.user.jobTitle = res.jobTitle;
|
||
authenticated.user.companyName = res.companyName;
|
||
|
||
bindProps('#header-username', null, null, (res.firstName || res.username), null)
|
||
bindProps('#header-avatar', null, res.avatar, null, null)
|
||
bindProps('#header-user-plug', res.profileUrl, null, res.realName, null)
|
||
bindProps('#header-user-edit', '/users/' + res.id + '/edit.html', null, null, null)
|
||
bindProps('#header-dropdown-manage-email', '/newsletters/' + res.id + '/manage.html', null, null, null)
|
||
bindProps('#dropdown-view-profile', res.profileUrl, null, null, null)
|
||
bindProps('#drafts-link', '/users/' + res.id + '/drafts.html', null, null, null)
|
||
|
||
if (res.isAdmin) {
|
||
// Construct backwards so the #after call places elements in the correct order
|
||
const firstUserAction = document.querySelector('#first-user-action')
|
||
const adminConsoleItem = document.createElement('li')
|
||
const adminConsoleLink = createLink('/dzone/staff/index.html', 'Admin Console')
|
||
adminConsoleItem.appendChild(adminConsoleLink)
|
||
firstUserAction.after(adminConsoleItem)
|
||
|
||
const moderationItem = document.createElement('li')
|
||
const moderationLink = createLink('/moderation/list.html', 'Moderation')
|
||
moderationItem.appendChild(moderationLink)
|
||
firstUserAction.after(moderationItem)
|
||
|
||
const bountyModerationItem = document.createElement('li')
|
||
const bountyModerationLink = createLink('/moderation/bounties', 'Bounty Moderation')
|
||
bountyModerationItem.appendChild(bountyModerationLink)
|
||
firstUserAction.after(bountyModerationItem)
|
||
}
|
||
|
||
authenticated.isAuthenticated = res.authenticated;
|
||
authenticated.isAdmin = res.isAdmin;
|
||
|
||
authenticatedBlock.classList.add('shown')
|
||
}
|
||
}).catch(function (result) {
|
||
console.error(result)
|
||
})
|
||
|
||
/**
|
||
* Binds different properties to the selected element.
|
||
*
|
||
* @param selector - Selector to select the element
|
||
* @param href - href attribute value
|
||
* @param src - src attribute value
|
||
* @param innerHTML - innerHTML property value
|
||
* @param innerText - innerText property value
|
||
*/
|
||
function bindProps(selector, href, src, innerHTML, innerText) {
|
||
const element = document.querySelector(selector)
|
||
if (element) {
|
||
if (href) element.href = href
|
||
if (src) element.src = src
|
||
if (innerHTML) element.innerHTML = innerHTML
|
||
if (innerText) element.innerText = innerText
|
||
}
|
||
}
|
||
|
||
/**
|
||
* Creates a new link element.
|
||
*
|
||
* @param href - href attribute value
|
||
* @param innerText - innerText property value
|
||
* @returns {HTMLAnchorElement} The generated link element
|
||
*/
|
||
function createLink(href, innerText) {
|
||
const link = document.createElement('a')
|
||
link.href = href
|
||
link.innerText = innerText
|
||
|
||
return link
|
||
}
|
||
</script><script>
|
||
const userHeader = document.querySelector('#user-header')
|
||
const userDropdown = document.querySelector('#user-dropdown')
|
||
const postDropdown = document.querySelector('#post-button')
|
||
const postMenu = document.querySelector('#post-menu')
|
||
|
||
let userDropdownOpen = false
|
||
let postDropdownOpen = false
|
||
|
||
document.addEventListener('click', function(event) {
|
||
if (postDropdown && postDropdown.contains(event.target)) {
|
||
setUserDropdown(false)
|
||
setPostDropdown(!postDropdownOpen)
|
||
} else if (userHeader && userHeader.contains(event.target)) {
|
||
setPostDropdown(false)
|
||
setUserDropdown(!userDropdownOpen)
|
||
} else {
|
||
setUserDropdown(false)
|
||
setPostDropdown(false)
|
||
}
|
||
})
|
||
|
||
function setUserDropdown(value) {
|
||
userDropdownOpen = value
|
||
if (userDropdownOpen) {
|
||
if (userDropdown) {
|
||
userDropdown.classList.add('open')
|
||
}
|
||
} else {
|
||
if (userDropdown) {
|
||
userDropdown.classList.remove('open')
|
||
}
|
||
}
|
||
}
|
||
|
||
function setPostDropdown(value) {
|
||
postDropdownOpen = value
|
||
if (postDropdownOpen) {
|
||
if (postMenu) {
|
||
postMenu.classList.add('open')
|
||
}
|
||
} else {
|
||
if (postMenu) {
|
||
postMenu.classList.remove('open')
|
||
}
|
||
}
|
||
}
|
||
</script><script>
|
||
document.addEventListener("alpine:init", () => {
|
||
Alpine.store('global', {
|
||
executeHttp(path, body, method) {
|
||
const options = {
|
||
method: method,
|
||
headers: {
|
||
[csrf.header]: csrf.token
|
||
}
|
||
};
|
||
|
||
if (method !== 'GET') {
|
||
options.body = JSON.stringify(body);
|
||
options.headers = {
|
||
...options.headers,
|
||
'Content-Type': 'application/json; charset=UTF-8'
|
||
};
|
||
}
|
||
|
||
return new Promise((resolve, reject) => {
|
||
fetch(path, options)
|
||
.then(res => {
|
||
if (!res.ok) {
|
||
reject(res);
|
||
} else {
|
||
resolve(res);
|
||
}
|
||
})
|
||
.catch(err => reject(err));
|
||
});
|
||
},
|
||
getFromService(path) {
|
||
return this.executeHttp(path, null, 'GET');
|
||
},
|
||
postToService(path, body = {}) {
|
||
return this.executeHttp(path, body, 'POST');
|
||
},
|
||
putToService(path, body = {}) {
|
||
return this.executeHttp(path, body, 'PUT');
|
||
}
|
||
});
|
||
});
|
||
</script>
|
||
<link rel="stylesheet" media="all" href="https://dz2cdn1.dzone.com/themes/dz20/ftl/colors.css">
|
||
<link rel="stylesheet" media="all" href="https://dz2cdn1.dzone.com/themes/dz20/ftl/article/styles.css">
|
||
|
||
|
||
|
||
|
||
|
||
<div id="body-container">
|
||
<div id="announcement-container-outer">
|
||
<div id="announcement-previous">
|
||
<i class="icon-angle-left"></i>
|
||
</div>
|
||
<div id="announcement-next">
|
||
<i class="icon-angle-right"></i>
|
||
</div>
|
||
<div id="announcement-container">
|
||
<div class="announcement announcement-count-1"
|
||
data-position="1">
|
||
<div class="body"><p><strong>Could your team report a vulnerability within 24 hours? </strong>Find out on September 23.</p></div>
|
||
<div class="spacer"></div>
|
||
<a href="https://cvent.me/O32zXR?utm_source=Announcements&utm_medium=DzoneWeb&utm_campaign=QtGroup-0923" target="_blank">
|
||
<button>Assess Your CRA Readiness</button>
|
||
</a>
|
||
</div>
|
||
</div>
|
||
</div>
|
||
<script type="text/javascript" async>
|
||
(function() {
|
||
let announcementPosition = 1;
|
||
let minAnnouncementPosition = -1;
|
||
let maxAnnouncementPosition = -1;
|
||
|
||
const announcementPrevBtn = document.querySelector('#announcement-previous');
|
||
const announcementNextBtn = document.querySelector('#announcement-next');
|
||
|
||
function withAnnouncements(callback) {
|
||
const announcements = document.querySelectorAll('#announcement-container .announcement');
|
||
for (let announcement of announcements) {
|
||
callback(announcement);
|
||
}
|
||
}
|
||
|
||
function initAnnouncementVars() {
|
||
document.querySelector(':root').style.setProperty('--mobile-announcement-separator-width', '1px');
|
||
withAnnouncements(function(announcement) {
|
||
const pos = parseInt(announcement.getAttribute('data-position'));
|
||
minAnnouncementPosition = minAnnouncementPosition === -1 ? pos : Math.min(minAnnouncementPosition, pos);
|
||
maxAnnouncementPosition = maxAnnouncementPosition === -1 ? pos : Math.max(maxAnnouncementPosition, pos);
|
||
});
|
||
|
||
if (document.querySelector('.announcementBarContainer')) {
|
||
document.querySelector(':root').style.setProperty('--body-top-padding', '0');
|
||
}
|
||
|
||
if (maxAnnouncementPosition <= 0) {
|
||
document.querySelector(':root').style.setProperty('--body-top-padding', '0');
|
||
}
|
||
|
||
sizeToFullWhenOneEntryOnMobile();
|
||
}
|
||
|
||
function setAnnouncementPosition(position) {
|
||
if (window.outerWidth >= 890) {
|
||
return; // we do not need to change the position, since we can display everything on desktop.
|
||
}
|
||
|
||
// Make the announcement cyclical
|
||
if (minAnnouncementPosition !== -1 && maxAnnouncementPosition !== -1) {
|
||
if (position > maxAnnouncementPosition) {
|
||
position = minAnnouncementPosition; // overflow to the first announcement
|
||
} else if (position < minAnnouncementPosition) {
|
||
position = maxAnnouncementPosition; // underflow to the last announcement
|
||
}
|
||
announcementPosition = position;
|
||
}
|
||
|
||
const shownAnnouncements = [];
|
||
|
||
let reverseFlex = false; // should only be true when the first and last items are showing
|
||
|
||
// Now that the position is valid, apply the transforms
|
||
withAnnouncements(function(announcement) {
|
||
const pos = parseInt(announcement.getAttribute('data-position'));
|
||
const isWrapped = position === maxAnnouncementPosition && pos === minAnnouncementPosition; // showing first + last at same time
|
||
const doesNextQualify = window.outerWidth >= 500 && (pos === position + 1 || isWrapped);
|
||
|
||
if (pos === position || doesNextQualify) {
|
||
shownAnnouncements.push(announcement);
|
||
} else {
|
||
announcement.style.display = 'none';
|
||
}
|
||
|
||
announcement.style.opacity = 0.0;
|
||
|
||
if (isWrapped) {
|
||
reverseFlex = true;
|
||
}
|
||
});
|
||
|
||
for (let announcement of shownAnnouncements) {
|
||
announcement.style.display = 'flex';
|
||
announcement.style.opacity = 1.0;
|
||
}
|
||
|
||
const announcementContainer = document.querySelector('#announcement-container');
|
||
if (announcementContainer) {
|
||
announcementContainer.style.flexDirection = reverseFlex ? 'row-reverse' : 'row';
|
||
}
|
||
}
|
||
|
||
function resetAnnouncements() {
|
||
announcementPosition = 1;
|
||
const announcementContainer = document.querySelector('#announcement-container');
|
||
if (announcementContainer) {
|
||
announcementContainer.style.flexDirection = 'row';
|
||
}
|
||
withAnnouncements(function(announcement) {
|
||
announcement.style.opacity = 1.0;
|
||
announcement.style.display = 'flex';
|
||
});
|
||
}
|
||
|
||
function sizeToFullWhenOneEntryOnMobile() {
|
||
if (maxAnnouncementPosition <= 2 && announcementPrevBtn && announcementNextBtn) {
|
||
announcementPrevBtn.style.display = maxAnnouncementPosition === 2 && window.outerWidth < 500 ? 'flex' : 'none';
|
||
announcementNextBtn.style.display = maxAnnouncementPosition === 2 && window.outerWidth < 500 ? 'flex' : 'none';
|
||
}
|
||
if (maxAnnouncementPosition === 1 && window.outerWidth >= 500 && window.outerWidth < 890) {
|
||
document.querySelector(':root').style.setProperty('--mobile-announcement-separator-width', '0');
|
||
document.querySelector('#announcement-container .announcement').style.maxWidth = '100%';
|
||
}
|
||
}
|
||
|
||
function resetAnnouncementsOnResize() {
|
||
announcementPosition = 1; // we want to reset the announcement position every resize
|
||
if (window.outerWidth >= 890) { // 4 announcements can be shown (215px * 4) + separator padding
|
||
resetAnnouncements();
|
||
} else { // if we're still on mobile, set the position to normalize things after resize
|
||
setAnnouncementPosition(announcementPosition);
|
||
sizeToFullWhenOneEntryOnMobile();
|
||
}
|
||
}
|
||
|
||
window.addEventListener('resize', resetAnnouncementsOnResize);
|
||
|
||
initAnnouncementVars();
|
||
setAnnouncementPosition(announcementPosition); // sets the min & max positions as well as initializes transforms
|
||
|
||
if (announcementPrevBtn) {
|
||
announcementPrevBtn.onclick = function() {
|
||
setAnnouncementPosition(announcementPosition - 1);
|
||
};
|
||
}
|
||
|
||
if (announcementNextBtn) {
|
||
announcementNextBtn.onclick = function() {
|
||
setAnnouncementPosition(announcementPosition + 1);
|
||
};
|
||
}
|
||
})(); </script>
|
||
<div id="ftl-article" class="trending-article-body">
|
||
<aside class="trending-sidebar" aria-labelledby="related-sidebar-heading">
|
||
<div class="trending">
|
||
<h2 id="related-sidebar-heading">Related</h2>
|
||
<div class="trending-separator"></div>
|
||
<ul>
|
||
<li class="item">
|
||
<a href="/articles/streaming-optimization-kafka-delta" class="related-link">End-to-End Streaming Optimization: Kafka to Delta With Exactly-Once Guarantees</a>
|
||
</li>
|
||
<li class="item">
|
||
<a href="/articles/setting-up-local-kafka-container-for-spring-boot-application" class="related-link">Setting Up Local Kafka Container for Spring Boot Application</a>
|
||
</li>
|
||
<li class="item">
|
||
<a href="/articles/nodejs-walkthrough-build-a-simple-event-driven-app" class="related-link">Node.js Walkthrough: Build a Simple Event-Driven Application With Kafka</a>
|
||
</li>
|
||
<li class="item">
|
||
<a href="/articles/application-integration-with-flask-kakfa-and-api-l" class="related-link">Automated Application Integration With Flask, Kakfa, and API Logic Server</a>
|
||
</li>
|
||
</ul>
|
||
</div>
|
||
</aside>
|
||
<div class="container-fluid body trending-article-fluid">
|
||
<div class="row">
|
||
<div class="col-md-12">
|
||
<div class="articles-wrap">
|
||
<div class="ad-container">
|
||
<div id="div-gpt-ad-1435246566686-0" class="ads-billboard-article dz2_article_billboard_new" data-gpt-slot="top"></div>
|
||
</div>
|
||
|
||
|
||
<div class="article-stream widget-top-border">
|
||
<div class="article-main">
|
||
<div class="content-right-images">
|
||
<div id="div-gpt-ad-1435246566686-2" class="sidebar-ad dz2_article_halfpage_new" data-gpt-slot="sidebar1"></div>
|
||
<div class="trending-separator"></div>
|
||
<aside class="trending" aria-labelledby="trending-sidebar-heading">
|
||
<h2 id="trending-sidebar-heading">Trending</h2>
|
||
<ul>
|
||
<li class="item">
|
||
<a href="/articles/detect-ai-images-csharp" class="trending-link" target="_self">How to Detect AI-Generated Images in C# Using an API</a>
|
||
</li>
|
||
<li class="item">
|
||
<a href="/articles/shift-left-without-losing-the-audit-trail-test-aut" class="trending-link" target="_self">Shift-Left Without Losing the Audit Trail: Test Automation for Regulated Surgical Software</a>
|
||
</li>
|
||
<li class="item">
|
||
<a href="/articles/goose-agentgateway-security" class="trending-link" target="_self">Part 2: Securing and Scaling Goose-to-Java Agent Traffic With agentgateway</a>
|
||
</li>
|
||
<li class="item">
|
||
<a href="/articles/exploration-vs-exploitation" class="trending-link" target="_self">Exploration vs Exploitation: Why It Matters and the Engineer’s Role</a>
|
||
</li>
|
||
</ul>
|
||
</aside>
|
||
</div>
|
||
<script type="application/ld+json">
|
||
{
|
||
"@context": "https://schema.org",
|
||
"@type": "Article",
|
||
"headline": "Interpreting Kafka's Exactly-Once Semantics",
|
||
"author": [{"image":{"@type":"ImageObject","caption":"Rahul Agarwal","url":"https://secure.gravatar.com/avatar/9e0ddba41071e650b9c0008e4ebd8167?d=identicon&r=PG"},"@type":"Person","worksFor":{"@type":"Organization","name":"TCS"},"name":"Rahul Agarwal","url":"https://dzone.com/users/3356344/rahulag.html"}],
|
||
"audience": "software developers",
|
||
"keywords": "kafka architecture,big data,data streaming,apache kafka tutorial",
|
||
"timeRequired": "PT5M",
|
||
"commentCount": 2,
|
||
"wordCount": "1041",
|
||
"accessMode": "textual, visual",
|
||
"datePublished": "2019-01-01T00:00:00Z",
|
||
|
||
"articleSection": "big-data-analytics-tutorials-tools-news",
|
||
"publisher": {
|
||
"@type": "Organization",
|
||
"name": "DZone",
|
||
"url": "https://dzone.com",
|
||
"logo": {
|
||
"@type": "ImageObject",
|
||
"url": "https://dzone.com/themes/dz20/images/dz_logo_2021_cropped.png"
|
||
}
|
||
},
|
||
"articleBody": "Until recently most organizations have been struggling to achieve the holy grail of message delivery, the exactly-once delivery semantic. Although this has been an out-of-the-box feature since Apache Kafkas 0.11, people are still slow in picking up this feature. Let's take a moment in understanding exactly-once semantics. What is the big deal about it and how does Kafka solve the problem? Apache Kafka offers following delivery guarantees. Let's understand what this really means: At Most Once Delivery: It guarantees that a particular message can either be delivered once or not at all. There can be a loss of messages but a message can never be delivered more than once. At Least Once Delivery: It guarantees that a particular message will always be delivered. It can be delivered multiple times but there will never be any messages lost. Exactly Once Delivery: It guarantees that all messages will always be delivered exactly once. Exactly once does not mean that there will be no failures or no retries. These are inevitable. The important thing is that the retries succeed. In other words, the result should be the same, whether it has been successfully processed exactly once or not. Why Exactly-Once Is Important There are certain use cases (like financial applications, IoT applications, and other streaming applications) which cannot afford anything less than exactly-once. You cannot afford to have duplicates or lose messages when depositing or withdrawing money from a bank account. It needs exactly-once as a final outcome. Why it Is Difficult to Achieve Assuming you have a small Kafka stream application with few inputs feeding partitions and few output partitions. The intent and expectation of the application is to receive data from input partitions, process the data, and write the same to output partitions. This is where one wants to achieve exactly-once as a guarantee. There are scenarios due to network glitches, system crashes, and other errors where duplicates get introduced during the process. Problem 1: Duplicate or Multiple Writes Refer to Figure 1a. Message m1 is being processed and being written to Topic B. Message m1 gets successfully written to Topic B (as m1') but the acknowledgment is not received. The reason could be, let's say, network delay and this eventually gets timed out. Figure 1a: Duplicate write problem. Figure 1b: Duplicate write problem due to retry. Since the application does not know that the message is already successfully written, as it never received the acknowledgment, it retries and leads to a duplicate write. Refer to Figure 1b. Message m1' gets rewritten to Topic B. This is a duplicate write issue and needs to be fixed. Problem 2: Reread Input Record Figure 2a: Reread problem due to the application crashing. Figure 2b: Reread problem when the crashed application restarts. Refer to Figure 2a. We have the same scenario as above, but, in this case, the stream application crashes just before committing the offset. Since the offset is not committed, when the stream application comes up again it rereads message m1 and processes the data again (Figure 2b). This again leads to duplicate writes of message m1 in Topic B. How Apache Kafka Helps Apache Kafka solves the above problems via exactly-once semantics using the following. Idempotent Producer Idempotency on the producer side can be achieved by preventing messages from being processed multiple times. This is achieved by persisting the message only once. With idempotency turned on, each Kafka message gets two things: a producer id (PID) and sequence number (seq). The PID assignment is completely transparent to users and is never exposed by clients. Figure 3: Idempotent Producer producerProps.put(\"enable.idempotence\", \"true\"); producerProps.put(\"transactional.id\", \"100\"); In the case of broker failure or client failure, during retry of message send, the topic will only accept messages that have a new unique sequence number and producer id. The broker automatically deduplicates any message(s) sent by this producer, ensuring idempotency. No additional code changes are required. Transactions Across Partitions To ensure that each message gets processed exactly-once, transactions can be used. Transactions have an all-or-nothing approach. They ensure that after picking a message, that the message can be transformed and atomically written to multiple topics/partitions along with an offset of the consumed message. Code Snippet for Atomic Transactions producer.initTransactions(); try { producer.beginTxn(); // ... read from input topic // ... transform producer.send(rec1); // topic A producer.send(rec2); // topic B producer.send(rec3); // topic C producer.sendOffsetsToTxn(offsetsToCommit, “group-id”); producer.commitTransaction(); } catch ( Exception e ) { producer.abortTransaction(); } Apache Kafka v0.11 introduced two components — the Transaction Coordinator and Transaction Log — which maintain the state of the atomic writes. The below diagram details a high-level flow of events that enables atomic transactions across various partitions: Figure 4: Transactions across a partition. initTransactions() registers a transactional.id with the coordinator.The coordinator bumps up the epoch of the PID so that previous instance of that PID is considered a zombie and fenced off. No writes in the future are accepted from these zombies.The producer adds a partition with the coordinator when the producer is about to send data to a partition.The transaction coordinator keeps the state of each transaction it owns in memory, and also writes that state to the transaction log (partition information, in this case).The producer sends data to the actual partitions.The producer initiates a commit transaction and, as a result, the coordinator begins the two-phase commit protocol.This is where the first phase begins and the coordinator updates the transaction log to “prepare_commit”.The coordinator then begins Phase 2, where it writes the transaction commit markers to the topic-partitions which are part of the transaction.After writing the markers, the transaction coordinator marks the transaction as “committed.” Transactional Consumer If a consumer is transactional, we should use the isolation level, read_committed. This ensures that it reads only committed data. The default value of isolation.level is read_uncommitted. This just a high-level view of how transactions work in Apache Kafka. I'd recommend exploring the docs if you're interested in taking a deeper dive. Conclusion In this post, we talked about various delivery guarantee semantics such as at-least-once, at-most-once, and exactly-once. We also talked about why exactly-once is important, the issues in the way of achieving exactly-once, and how Kafka supports it out-of-the-box with a simple configuration and minimal coding. References Transaction in Apache Kafka Enabling-exactly-kafka-streams",
|
||
"mainEntityOfPage": {
|
||
"@type": "WebPage",
|
||
"@id": "https://dzone.com/articles/interpreting-kafkas-exactly-once-semantics"
|
||
},
|
||
"image": {
|
||
"@type": "ImageObject",
|
||
"url": "https://dz2cdn1.dzone.com/storage/article-thumb/10954057-thumb.jpg"
|
||
}
|
||
}
|
||
</script>
|
||
|
||
<script type="application/ld+json">
|
||
{
|
||
"@context": "https://schema.org",
|
||
"@type": "BreadcrumbList",
|
||
"itemListElement": [
|
||
{
|
||
"@type": "ListItem",
|
||
"position": 1,
|
||
"name": "DZone",
|
||
"item": "https://dzone.com"
|
||
},
|
||
{
|
||
"@type": "ListItem",
|
||
"position": 2,
|
||
"name": "Data Engineering",
|
||
"item": "https://dzone.com/data-engineering"
|
||
},
|
||
{
|
||
"@type": "ListItem",
|
||
"position": 3,
|
||
"name": "Big Data",
|
||
"item": "https://dzone.com/big-data"
|
||
},
|
||
{
|
||
"@type": "ListItem",
|
||
"position": 4,
|
||
"name": "Interpreting Kafka's Exactly-Once Semantics",
|
||
"item": "https://dzone.com/articles/interpreting-kafkas-exactly-once-semantics"
|
||
}
|
||
]
|
||
}
|
||
|
||
</script>
|
||
|
||
<article>
|
||
<div class="content">
|
||
<div class="header">
|
||
<ol class="breadcrumb">
|
||
<li class="server"><a href="https://dzone.com">DZone</a></li>
|
||
<li class="server"><a href="https://dzone.com/data-engineering">Data Engineering</a></li>
|
||
<li class="server"><a href="https://dzone.com/big-data">Big Data</a></li>
|
||
<li class="active server">Interpreting Kafka's Exactly-Once Semantics</li>
|
||
</ol>
|
||
|
||
|
||
<div class="header-title">
|
||
<div class="title">
|
||
<h1 class="article-title">Interpreting Kafka's Exactly-Once Semantics</h1>
|
||
</div>
|
||
|
||
<div class="subhead">
|
||
<p>Apache Kafka comes out-of-the-box packed with great data science features. We take a look at few of them in this post.</p>
|
||
</div>
|
||
|
||
<div class="publish-meta">
|
||
By<span style="user-select: none;"> </span>
|
||
<div class="article-author-meta">
|
||
<img src="https://dz2cdn1.dzone.com/thumbnail?fid=10017182&w=80" class="avatar" alt="Rahul Agarwal user avatar" width="40">
|
||
<div class="author-info">
|
||
<span class="author-name">
|
||
<a href="/users/3356344/rahulag.html" rel="nofollow" data-core-user="false">Rahul Agarwal</a>
|
||
</span>
|
||
</div>
|
||
|
||
|
||
|
||
·
|
||
</div>
|
||
<span class="author-date">
|
||
Jan. 01, 19
|
||
</span>
|
||
·
|
||
<span>Tutorial</span>
|
||
</div>
|
||
</div>
|
||
</div>
|
||
|
||
<div class="author-n-useraction">
|
||
<div class="like action" x-data="engagementModal(articleId)">
|
||
<span id="activity-like-icon" class="dz-like icon-thumbs-up" x-on:click="updateStore()"></span>
|
||
<span class="action-label like-text" x-on:click="open()" x-cloak>
|
||
<span>Likes</span>
|
||
<span id="activity-like-counter" class="like-count">(5)</span>
|
||
</span>
|
||
<template x-teleport="body">
|
||
<div class="engagement-overlay" x-show="$store.article.engagement.open && nodeId === $store.article.id" x-on:keyup.escape.window="close()">
|
||
<div class="engagement-modal">
|
||
<div class="inner" x-on:click.outside="close()">
|
||
<div class="header">
|
||
<div class="title">Likes</div>
|
||
<button class="close" x-on:click="close()"></button>
|
||
</div>
|
||
<div class="content">
|
||
<div x-show="$store.article.engagement.initializing" class="loading-screen">
|
||
<i class="icon icon-spin3 anim-spin"></i>
|
||
</div>
|
||
<div x-show="!$store.article.engagement.initializing">
|
||
<template x-for="user in $store.article.engagement.users" :key="user.id">
|
||
<div class="media">
|
||
<div class="media-left">
|
||
<img class="avatar"
|
||
x-bind:src="user.profile.profileImage"
|
||
loading="lazy"
|
||
width="50"
|
||
height="50"
|
||
>
|
||
</div>
|
||
<div class="media-right">
|
||
<a x-bind:href="user.computed.url" x-html="user.profile.name"></a>
|
||
<div x-show="formatJobData(user)" x-html="formatJobData(user)"></div>
|
||
</div>
|
||
</div>
|
||
</template>
|
||
</div>
|
||
<div x-show="isDataUnavailable()" class="center-screen">
|
||
<div x-show="!$store.article.engagement.unauthorized">
|
||
<div>There are no likes...yet! 👀</div>
|
||
<div>Be the first to like this post!</div>
|
||
</div>
|
||
<div x-show="$store.article.engagement.unauthorized">
|
||
<div>It looks like you're not logged in.</div>
|
||
<div><a href="/users/login.html">Sign in</a> to see who liked this post!</div>
|
||
</div>
|
||
</div>
|
||
<div x-show="isFooterShowing()">
|
||
<div class="footer">
|
||
<button class="btn btn-primary" x-on:click="fetchEngagements()"
|
||
x-bind:disabled="$store.article.engagement.loading"
|
||
>
|
||
Load More
|
||
<i x-show="$store.article.engagement.loading" class="icon icon-spin3 anim-spin"></i>
|
||
</button>
|
||
</div>
|
||
</div>
|
||
</div>
|
||
</div>
|
||
</div>
|
||
</div>
|
||
</template> </div>
|
||
|
||
<div class="action comment-action">
|
||
<span class="comment">
|
||
<i class="icon-comment"></i>
|
||
<span class="action-label">Comment</span>
|
||
<span id="activity-comment-counter" class="comment-count"></span>
|
||
</span>
|
||
</div>
|
||
|
||
<div class="save action">
|
||
<div id="activity-save-icon" class="save icon-star-empty">
|
||
<span id="activity-save-text" class="action-label">Save</span>
|
||
</div>
|
||
</div>
|
||
|
||
<div class="tweet action">
|
||
<a id="tweet-link" href="" class="title" target="_blank">
|
||
<span><i class="icon-twitter"></i></span>
|
||
<span class="action-label">Tweet</span>
|
||
</a>
|
||
</div>
|
||
|
||
<div class="linkedin action">
|
||
<a id="linkedin-link" href="https://www.linkedin.com/sharing/share-offsite/?url=https://dzone.com/articles/interpreting-kafkas-exactly-once-semantics" class="title" target="_blank">
|
||
<span><i class="icon-linkedin-1"></i></span>
|
||
<span class="action-label">Share</span>
|
||
</a>
|
||
</div>
|
||
|
||
<div class="right-most">
|
||
<div id="activity-view-container" class="article-views action">
|
||
<i class="icon-eye"></i>
|
||
<span class="action-label view-count">28.6K Views</span>
|
||
</div>
|
||
</div>
|
||
</div>
|
||
|
||
<div class="signin-prompt">
|
||
<p>Join the DZone community and get the full member experience.</p>
|
||
<a id="article-signin-prompt" href="/static/registration.html">Join For Free</a>
|
||
</div>
|
||
<div class="arrow-down"></div>
|
||
|
||
<div id="top-bumper-container"></div>
|
||
|
||
<div>
|
||
<div class="content-html"><p pid="1">Until recently most organizations have been struggling to achieve the holy grail of message delivery, the exactly-once delivery semantic. Although this has been an out-of-the-box feature since Apache Kafkas 0.11, people are still slow in picking up this feature. Let's take a moment in understanding exactly-once semantics. What is the big deal about it and how does Kafka solve the problem?</p>
|
||
<p pid="2">Apache Kafka offers following delivery guarantees. Let's understand what this really means:</p>
|
||
<ul>
|
||
<li><p pid="7"><strong> At Most Once Delivery: </strong>It guarantees that a particular message can either be delivered once or not at all. There can be a loss of messages but a message can never be delivered more than once.</p></li>
|
||
<li><p pid="10"><strong>At Least Once Delivery</strong>: It guarantees that a particular message will always be delivered. It can be delivered multiple times but there will never be any messages lost.</p></li>
|
||
<li><p pid="13"><strong>Exactly Once Delivery</strong>: It guarantees that all messages will always be delivered exactly once. Exactly once does not mean that there will be no failures or no retries. These are inevitable. The important thing is that the retries succeed. In other words, the result should be the same, whether it has been successfully processed exactly once or not.</p></li>
|
||
</ul>
|
||
<h2 pid="17">Why Exactly-Once Is Important</h2>
|
||
<p pid="7">There are certain use cases (like financial applications, IoT applications, and other streaming applications) which cannot afford anything less than exactly-once. You cannot afford to have duplicates or lose messages when depositing or withdrawing money from a bank account. It needs exactly-once as a final outcome.</p>
|
||
<h2 pid="21">Why it Is Difficult to Achieve</h2>
|
||
<p pid="9">Assuming you have a small Kafka stream application with few inputs feeding partitions and few output partitions. The intent and expectation of the application is to receive data from input partitions, process the data, and write the same to output partitions. This is where one wants to achieve exactly-once as a guarantee. There are scenarios due to network glitches, system crashes, and other errors where duplicates get introduced during the process.</p>
|
||
<h3 pid="32">Problem 1: Duplicate or Multiple Writes</h3>
|
||
<p pid="11">Refer to Figure 1a. Message <em>m1</em> is being processed and being written to Topic B. Message <em>m1 </em>gets successfully written to Topic B (as <em>m1'</em>) but the acknowledgment is not received. The reason could be, let's say, network delay and this eventually gets timed out.<img alt="Image title" class="fr-fin fr-dib" src="https://dz2cdn1.dzone.com/storage/temp/10922695-figure-1a-duplicate-write-problem.png" width="727"></p>
|
||
<p pid="12" style="text-align: center;"><em>Figure 1a: Duplicate write problem.</em></p>
|
||
<p pid="13"><br></p>
|
||
<p pid="14"><img alt="Image title" class="fr-fin fr-dib" src="https://dz2cdn1.dzone.com/storage/temp/10922662-figure-1b-duplicate-write-problem-due-to-retry.png" width="748"></p>
|
||
<p pid="15" style="text-align: center;"><em>Figure 1b: Duplicate write problem due to retry.</em></p>
|
||
<p pid="17">Since the application does not know that the message is already successfully written, as it never received the acknowledgment, it retries and leads to a duplicate write. Refer to Figure 1b. Message <em>m1' </em>gets rewritten to Topic B. This is a duplicate write issue and needs to be fixed.</p>
|
||
<h3 pid="48">Problem 2: Reread Input Record</h3>
|
||
<p pid="19"><img alt="Image title" class="fr-fin fr-dib" src="https://dz2cdn1.dzone.com/storage/temp/10922681-figure-2a-re-read-problem-due-to-application-crash.png" width="731"></p>
|
||
<p pid="20" style="text-align: center;"><em>Figure 2a: Reread problem due to the application crashing.</em></p>
|
||
<p pid="21"><img alt="Image title" class="fr-fin fr-dib" src="https://dz2cdn1.dzone.com/storage/temp/10922682-figure-2b-re-read-problem-when-crashed-application.png" width="750"></p>
|
||
<p pid="22" style="text-align: center;"><em>Figure 2b: Reread problem when the crashed application restarts.</em></p>
|
||
<p pid="23">Refer to Figure 2a. We have the same scenario as above, but, in this case, the stream application crashes just before committing the offset. Since the offset is not committed, when the stream application comes up again it rereads message m1 and processes the data again (Figure 2b). This again leads to duplicate writes of message m1 in Topic B.</p>
|
||
<h2 pid="59">How Apache Kafka Helps</h2>
|
||
<p pid="25">Apache Kafka solves the above problems via exactly-once semantics using the following.</p>
|
||
<h3 pid="62">Idempotent Producer</h3>
|
||
<p pid="26">Idempotency on the producer side can be achieved by preventing messages from being processed multiple times. This is achieved by persisting the message only once. With idempotency turned on, each Kafka message gets two things: a producer id (PID) and sequence number (seq). The PID assignment is completely transparent to users and is never exposed by clients.</p>
|
||
<p pid="27"><img alt="Image title" class="fr-fin fr-dib" src="https://dz2cdn1.dzone.com/storage/temp/10928558-figure-3-idempotent-producer.png" width="529"></p>
|
||
<p pid="28" style="text-align: center;"><em>Figure 3: Idempotent Producer</em></p>
|
||
<pre><code lang="text/x-java">producerProps.put("enable.idempotence", "true");
|
||
producerProps.put("transactional.id", "100");</code></pre>
|
||
<p pid="31">In the case of broker failure or client failure, during retry of message send, the topic will only accept messages that have a new unique sequence number and producer id. The broker automatically deduplicates any message(s) sent by this producer, ensuring idempotency. No additional code changes are required.</p>
|
||
<h3 pid="77">Transactions Across Partitions</h3>
|
||
<p pid="33">To ensure that each message gets processed exactly-once, transactions can be used. Transactions have an all-or-nothing approach. They ensure that after picking a message, that the message can be transformed and atomically written to multiple topics/partitions along with an offset of the consumed message.</p>
|
||
<p pid="34"><strong>Code Snippet for Atomic Transactions</strong></p>
|
||
<pre><code lang="text/x-java">producer.initTransactions();
|
||
try {
|
||
|
||
producer.beginTxn();
|
||
// ... read from input topic
|
||
// ... transform
|
||
|
||
producer.send(rec1); // topic A
|
||
producer.send(rec2); // topic B
|
||
producer.send(rec3); // topic C
|
||
|
||
producer.sendOffsetsToTxn(offsetsToCommit, “group-id”);
|
||
|
||
producer.commitTransaction();
|
||
} catch ( Exception e ) {
|
||
producer.abortTransaction();
|
||
}</code></pre>
|
||
<p pid="35">Apache Kafka v0.11 introduced two components — the Transaction Coordinator and Transaction Log — which maintain the state of the atomic writes.</p>
|
||
<p pid="37">The below diagram details a high-level flow of events that enables atomic transactions across various partitions:</p>
|
||
<p pid="38"><img alt="Image title" class="fr-image-dropped fr-fin fr-dib" src="https://dz2cdn1.dzone.com/storage/temp/10934601-figure-4-transactions-across-partition.png" width="728"></p>
|
||
<p pid="39" style="text-align: center;"><em>Figure 4: Transactions across a partition.</em></p>
|
||
<ol>
|
||
<li><code>initTransactions()</code> registers a <code>transactional.id</code><span id="_tmp_pre_3"> </span>with the coordinator.</li>
|
||
<li>The coordinator bumps up the epoch of the PID so that previous instance of that PID is considered a zombie and fenced off. No writes in the future are accepted from these zombies.</li>
|
||
<li>The producer adds a partition with the coordinator when the producer is about to send data to a partition.</li>
|
||
<li>The transaction coordinator keeps the state of each transaction it owns in memory, and also writes that state to the transaction log (partition information, in this case).</li>
|
||
<li>The producer sends data to the actual partitions.</li>
|
||
<li>The producer initiates a commit transaction and, as a result, the coordinator begins the two-phase commit protocol.</li>
|
||
<li>This is where the first phase begins and the coordinator updates the transaction log to “prepare_commit”.</li>
|
||
<li>The coordinator then begins Phase 2, where it writes the transaction commit markers to the topic-partitions which are part of the transaction.</li>
|
||
<li>After writing the markers, the transaction coordinator marks the transaction as “committed.”</li>
|
||
</ol>
|
||
<h3 pid="84">Transactional Consumer</h3>
|
||
<p pid="42">If a consumer is transactional, we should use the isolation level, <code>read_committed</code>. This ensures that it reads only committed data.</p>
|
||
<p pid="43">The default value of <code>isolation.level</code> is <code>read_uncommitted</code>.</p>
|
||
<p pid="44">This just a high-level view of how transactions work in Apache Kafka. I'd recommend exploring the <a href="https://kafka.apache.org/documentation/" target="_blank">docs</a> if you're interested in taking a deeper dive.</p>
|
||
<h2 pid="85">Conclusion</h2>
|
||
<p pid="45">In this post, we talked about various delivery guarantee semantics such as at-least-once, at-most-once, and exactly-once. We also talked about why exactly-once is important, the issues in the way of achieving exactly-once, and how Kafka supports it out-of-the-box with a simple configuration and minimal coding.</p>
|
||
<h2 pid="89">References</h2>
|
||
<ol>
|
||
<li><p pid="47"><a href="https://www.confluent.io/blog/transactions-apache-kafka/" target="_blank">Transaction in Apache Kafka</a></p></li>
|
||
<li><p pid="47"><a href="https://www.confluent.io/blog/enabling-exactly-kafka-streams/" target="_blank">Enabling-exactly-kafka-streams</a></p></li>
|
||
</ol></div>
|
||
</div>
|
||
|
||
<div id="bottom-bumper-container"></div>
|
||
<div class="article-tag-pill-container">
|
||
<span class="article-tag-pill">kafka</span>
|
||
<span class="article-tag-pill">Semantics (computer science)</span>
|
||
<span class="article-tag-pill">application</span>
|
||
<span class="article-tag-pill">Transaction log</span>
|
||
</div>
|
||
|
||
<div class="attribution">
|
||
<p>Opinions expressed by DZone contributors are their own.</p>
|
||
</div>
|
||
</div>
|
||
</article>
|
||
</div>
|
||
|
||
<div class="trending-separator goto"></div>
|
||
<aside class="trending goto" aria-labelledby="related-mobile-heading">
|
||
<h2 id="related-mobile-heading">Related</h2>
|
||
<ul>
|
||
<li class="item">
|
||
<a href="/articles/streaming-optimization-kafka-delta" class="goto-link related-link">End-to-End Streaming Optimization: Kafka to Delta With Exactly-Once Guarantees</a>
|
||
</li>
|
||
<li class="item">
|
||
<a href="/articles/setting-up-local-kafka-container-for-spring-boot-application" class="goto-link related-link">Setting Up Local Kafka Container for Spring Boot Application</a>
|
||
</li>
|
||
<li class="item">
|
||
<a href="/articles/nodejs-walkthrough-build-a-simple-event-driven-app" class="goto-link related-link">Node.js Walkthrough: Build a Simple Event-Driven Application With Kafka</a>
|
||
</li>
|
||
<li class="item">
|
||
<a href="/articles/application-integration-with-flask-kakfa-and-api-l" class="goto-link related-link">Automated Application Integration With Flask, Kakfa, and API Logic Server</a>
|
||
</li>
|
||
</ul>
|
||
</aside>
|
||
</div>
|
||
|
||
<div id="div-gpt-ad-1435246566686-11" class="ads-bottom-leaderboard dz2_article_bottom" data-gpt-slot="bottom"></div>
|
||
<div class="layout-card widget-top-border partner-resources-block" style="width:100%; margin-bottom: 1em;">
|
||
<div class="main-container">
|
||
<div class="featured-header">
|
||
<h2>
|
||
<span>Partner Resources</span>
|
||
</h2>
|
||
</div>
|
||
<div class="partner-resources-container">
|
||
<div id="div-gpt-ad-1435246566686-5" class="resource-block dz2_partner_resource_link" data-gpt-slot="partner" data-gpt-position="pr1"></div>
|
||
<div id="div-gpt-ad-1435246566686-6" class="resource-block dz2_partner_resource_link" data-gpt-slot="partner" data-gpt-position="pr2"></div>
|
||
<div id="div-gpt-ad-1435246566686-7" class="resource-block dz2_partner_resource_link" data-gpt-slot="partner" data-gpt-position="pr3"></div>
|
||
</div>
|
||
</div>
|
||
</div>
|
||
</div>
|
||
</div>
|
||
</div>
|
||
</div>
|
||
|
||
<div class="bottom-sticky-ad-container">
|
||
<span class="bottom-sticky-ad-close" title="close"
|
||
x-on:click="$el.parentElement.classList.add('closed')">×</span>
|
||
<div id="div-gpt-ad-1635294790718-12" class="bottom-sticky-ad dz2_sticky_footer_leaderboard" data-gpt-slot="bottomStickyFooter"></div>
|
||
</div>
|
||
|
||
<div class="modal fade bd-example-modal-lg" id="modal-message" tabindex="-1" role="dialog" aria-hidden="true">
|
||
<div class="modal-dialog">
|
||
<div class="modal-content">
|
||
<div class="modal-header"></div>
|
||
<div class="modal-body"></div>
|
||
</div>
|
||
</div>
|
||
</div>
|
||
</div>
|
||
</div>
|
||
|
||
<div class="comments-overlay"></div>
|
||
<div id="comment-box">
|
||
<div class="comment-box-wrapper">
|
||
<div id="comment-input-editor"></div>
|
||
</div>
|
||
<div class="info hidden"></div>
|
||
<div class="comments-content" style="display: none;">
|
||
<div class="comment-header">
|
||
<hr />
|
||
<span class="icon-comment">
|
||
<span class="numOfComments"></span> Comments
|
||
</span>
|
||
</div>
|
||
<div class="comments"></div>
|
||
</div>
|
||
</div>
|
||
|
||
<script async>var articleTitle = 'Interpreting Kafka\'s Exactly-Once Semantics';
|
||
var articleUrl = 'https://dzone.com/articles/interpreting-kafkas-exactly-once-semantics';
|
||
|
||
var retweetLink = document.querySelector('#tweet-link');
|
||
|
||
function retweet(event) {
|
||
event.preventDefault();
|
||
event.stopPropagation();
|
||
|
||
var twitter = 'https://twitter.com/intent/tweet';
|
||
var params = '?text=' + encodeURIComponent(articleTitle) + '&url=' + articleUrl + '&ref=dzone.com&via=DZoneInc';
|
||
var win = window.open(twitter + params, '_blank');
|
||
win.focus();
|
||
}
|
||
|
||
retweetLink.addEventListener('click', retweet);
|
||
|
||
function showStatusMessage(options) {
|
||
var modal = document.getElementById('modal-message');
|
||
|
||
if(modal) {
|
||
modal.classList.add(options.type);
|
||
var modalBody = modal.querySelector('.modal-content .modal-body');
|
||
var modalHeader = modal.querySelector('.modal-content .modal-header');
|
||
|
||
modalHeader.innerText = options.header ? options.header : '';
|
||
modalBody.innerText = options.body ? options.body : '';
|
||
|
||
$(modal).modal('show');
|
||
|
||
$(modal).on('hidden.bs.modal', function () {
|
||
modal.classList.remove(options.type);
|
||
});
|
||
}
|
||
}
|
||
|
||
function showConfirmMessage(options) {
|
||
var modal = document.getElementById('modal-message');
|
||
|
||
if(modal) {
|
||
modal.classList.add(options.type);
|
||
var modalBody = modal.querySelector('.modal-content .modal-body');
|
||
var modalHeader = modal.querySelector('.modal-content .modal-header');
|
||
|
||
modalHeader.innerText = options.header ? options.header : '';
|
||
modalBody.innerText = options.body ? options.body : '';
|
||
|
||
if (options.textarea) {
|
||
var textareaDiv = document.createElement('div');
|
||
var textareaLabel = document.createElement('label');
|
||
textareaLabel.setAttribute('for', 'modal-textarea');
|
||
textareaLabel.innerText = options.textarea.label;
|
||
|
||
var textarea = document.createElement('textarea');
|
||
textarea.id = 'modal-textarea';
|
||
textarea.placeholder = (options.textarea.placeholder || '');
|
||
textarea.setAttribute('rows', (options.textarea.rows || 3));
|
||
textarea.classList.add('form-control', 'not-resizable');
|
||
|
||
if (options.textarea.maxlength) {
|
||
textarea.maxLength = options.textarea.maxlength;
|
||
}
|
||
|
||
textareaDiv.appendChild(textareaLabel);
|
||
textareaDiv.appendChild(textarea);
|
||
modalBody.appendChild(textareaDiv);
|
||
}
|
||
|
||
var btnContainer = document.createElement('div');
|
||
btnContainer.classList.add('btn-container');
|
||
|
||
var noBtn = document.createElement('button');
|
||
noBtn.innerText = options.noBtnText ? options.noBtnText : 'No';
|
||
noBtn.classList.add('no-btn');
|
||
|
||
var yesBtn = document.createElement('button');
|
||
yesBtn.innerText = options.yesBtnText ? options.yesBtnText : 'Yes';
|
||
yesBtn.classList.add('yes-btn');
|
||
|
||
btnContainer.appendChild(noBtn);
|
||
btnContainer.appendChild(yesBtn);
|
||
|
||
modalBody.appendChild(btnContainer);
|
||
|
||
$(modal).modal('show');
|
||
|
||
$(noBtn).one('click', function() {
|
||
$(modal).modal('hide');
|
||
|
||
if(options.noCallback) {
|
||
$(modal).one('hidden.bs.modal', function () {
|
||
options.noCallback();
|
||
});
|
||
}
|
||
});
|
||
|
||
$(yesBtn).one('click', function() {
|
||
$(modal).modal('hide');
|
||
|
||
if(options.yesCallback) {
|
||
$(modal).one('hidden.bs.modal', function () {
|
||
options.yesCallback();
|
||
});
|
||
}
|
||
});
|
||
|
||
$(modal).on('hidden.bs.modal', function () {
|
||
modal.classList.remove(options.type);
|
||
});
|
||
}
|
||
}
|
||
|
||
function getSuspensionBody() {
|
||
return 'We regret to inform you that your DZone account has been suspended for violating our Guidelines. ' +
|
||
'Please reach out to editors@dzone.com if you would like additional information.';
|
||
}</script>
|
||
<style>.engagement-overlay {
|
||
width: 100%;
|
||
height: 100%;
|
||
position: fixed;
|
||
top: 0;
|
||
left: 0;
|
||
background: rgb(0, 0, 0, 0.5);
|
||
z-index: 10000;
|
||
}
|
||
|
||
.engagement-modal {
|
||
display: flex;
|
||
align-items: center;
|
||
justify-content: center;
|
||
position: fixed;
|
||
z-index: 10;
|
||
width: 100%;
|
||
height: 100%;
|
||
}
|
||
|
||
.engagement-modal .inner {
|
||
background-color: white;
|
||
border-radius: 0.5em;
|
||
margin: auto;
|
||
border: 1px solid #cccccc;
|
||
}
|
||
|
||
.engagement-modal .header {
|
||
padding: 20px 50px 10px 30px;
|
||
position: relative;
|
||
}
|
||
|
||
.engagement-modal .title {
|
||
font-size: 20px;
|
||
font-weight: bold;
|
||
color: #333333;
|
||
}
|
||
|
||
.engagement-modal .title:hover {
|
||
text-decoration: none;
|
||
}
|
||
|
||
.engagement-modal .close {
|
||
font-size: 18px;
|
||
position: absolute;
|
||
top: 18px;
|
||
right: 20px;
|
||
width: 32px;
|
||
height: 32px;
|
||
background: none;
|
||
border: none;
|
||
opacity: 0.8;
|
||
font-weight: bold;
|
||
text-shadow: 0 1px 0 #fff;
|
||
}
|
||
|
||
.engagement-modal .close:hover {
|
||
background-color: rgba(146, 148, 151, 0.2);
|
||
color: #000;
|
||
border-radius: 50%;
|
||
}
|
||
|
||
.engagement-modal .close:after {
|
||
content: '\2715';
|
||
}
|
||
|
||
.engagement-modal .content {
|
||
padding: 0 30px 20px;
|
||
width: min(450px, 90vw);
|
||
height: min(450px, 90vw);
|
||
scrollbar-width: thin;
|
||
overflow: auto;
|
||
overscroll-behavior: contain;
|
||
}
|
||
|
||
.engagement-modal .loading-screen,
|
||
.engagement-modal .content .center-screen {
|
||
display: flex;
|
||
justify-content: center;
|
||
align-items: center;
|
||
height: 100%;
|
||
font-size: 18px;
|
||
}
|
||
|
||
.engagement-modal .content .center-screen a {
|
||
color: var(--acc-ffffff-blue-1);
|
||
font-weight: bold;
|
||
}
|
||
|
||
.engagement-modal .loading-screen i {
|
||
font-size: 24px;
|
||
}
|
||
|
||
.engagement-modal .media-left,
|
||
.engagement-modal .media-right {
|
||
display: table-cell;
|
||
vertical-align: top;
|
||
}
|
||
|
||
.engagement-modal .media-left {
|
||
padding-right: 10px;
|
||
}
|
||
|
||
.engagement-modal .media-right {
|
||
padding-left: 10px;
|
||
}
|
||
|
||
.engagement-modal .media a {
|
||
color: black;
|
||
font-size: 16px;
|
||
}
|
||
|
||
.engagement-modal .avatar {
|
||
border-radius: 50%;
|
||
}
|
||
|
||
.engagement-modal .footer {
|
||
margin: 20px 0 0;
|
||
display: flex;
|
||
justify-content: center;
|
||
align-items: center;
|
||
background-color: unset !important;
|
||
border-top: none !important;
|
||
}
|
||
|
||
.engagement-modal .footer .btn {
|
||
border: 1px solid transparent;
|
||
}
|
||
|
||
.engagement-modal .footer .btn-primary {
|
||
color: #fff;
|
||
border-color: #2e6da4;
|
||
}
|
||
|
||
.engagement-modal .footer button {
|
||
background-color: var(--acc-ffffff-blue-2);
|
||
padding: 6px 12px;
|
||
border-radius: 4px;
|
||
}
|
||
|
||
.engagement-modal .footer button:hover {
|
||
filter: brightness(1.2);
|
||
}
|
||
|
||
@keyframes anim-spin {
|
||
0% {
|
||
transform: rotate(0deg);
|
||
}
|
||
100% {
|
||
transform: rotate(359deg);
|
||
}
|
||
}
|
||
|
||
.engagement-modal .anim-spin {
|
||
display: inline-block;
|
||
animation: anim-spin 2s infinite linear;
|
||
}</style>
|
||
<script>document.addEventListener('alpine:init', () => {
|
||
Alpine.data('engagementModal', (nodeId) => ({
|
||
|
||
nodeId: null,
|
||
|
||
init() {
|
||
this.nodeId = nodeId;
|
||
},
|
||
|
||
open() {
|
||
this.updateStore();
|
||
this.$store.article.engagement.open = true;
|
||
if (this.$store.article.engagement.page === 1 && !this.$store.article.engagement.unauthorized) {
|
||
this.$store.article.engagement.initializing = true;
|
||
this.fetchEngagements();
|
||
}
|
||
},
|
||
|
||
close() {
|
||
if (this.$store.article.engagement.open) {
|
||
this.$store.article.engagement.open = false;
|
||
}
|
||
},
|
||
|
||
updateStore() {
|
||
if (this.nodeId !== this.$store.article.id) {
|
||
this.$store.article.engagement.reset();
|
||
this.$store.article.id = this.nodeId;
|
||
}
|
||
},
|
||
|
||
fetchEngagements() {
|
||
if (this.$store.article.engagement.loading || !this.$store.article.engagement.additional) {
|
||
return;
|
||
}
|
||
|
||
this.$store.article.engagement.loading = true;
|
||
this.$store.global.getFromService('/services/nodes/' + this.$store.article.id + '/engagements?page=' + this.$store.article.engagement.page)
|
||
.then(res => {
|
||
res.json().then(data => {
|
||
for (let user of data.engagements) {
|
||
this.$store.article.engagement.users.push(user);
|
||
}
|
||
|
||
this.$store.article.engagement.additional = data.additional;
|
||
this.$store.article.engagement.page++;
|
||
});
|
||
})
|
||
.catch(err => {
|
||
err.json().then(data => {
|
||
if (data.error?.code === 4011) {
|
||
this.$store.article.engagement.unauthorized = true;
|
||
} else {
|
||
this.$store.modal_engagement_error.open();
|
||
}
|
||
});
|
||
})
|
||
.finally(() => {
|
||
// Allow the loader to gracefully exit
|
||
setTimeout(() => {
|
||
this.$store.article.engagement.loading = false;
|
||
this.$store.article.engagement.initializing = false;
|
||
}, 200);
|
||
});
|
||
},
|
||
|
||
formatJobData(user) {
|
||
if (user.profile.jobTitle && user.profile.companyName) {
|
||
return user.profile.jobTitle + ', ' + user.profile.companyName;
|
||
}
|
||
|
||
if (user.profile.jobTitle) {
|
||
return user.profile.jobTitle;
|
||
}
|
||
|
||
if (user.profile.companyName) {
|
||
return user.profile.companyName;
|
||
}
|
||
|
||
return null;
|
||
},
|
||
|
||
isDataUnavailable() {
|
||
return !this.$store.article.engagement.initializing && !this.$store.article.engagement.users.length;
|
||
},
|
||
|
||
isFooterShowing() {
|
||
return !this.$store.article.engagement.initializing
|
||
&& this.$store.article.engagement.additional
|
||
&& this.$store.article.engagement.page > 1;
|
||
}
|
||
}));
|
||
});
|
||
</script>
|
||
|
||
<div class="alpine-overlay" x-cloak x-show="$store.modal_engagement_error._open">
|
||
<div id="modal_engagement_error"
|
||
class="alpine-modal"
|
||
role="dialog"
|
||
tabindex="-1"
|
||
x-show="$store.modal_engagement_error._open"
|
||
x-on:click.self="$store.modal_engagement_error.dismissible && $store.modal_engagement_error.close()"
|
||
x-cloak
|
||
x-transition
|
||
>
|
||
<div class="dz-style modal-inner centered relative">
|
||
<button x-show="$store.modal_engagement_error.closeable"
|
||
class="btn-close"
|
||
x-on:click="$store.modal_engagement_error.close()"
|
||
aria-label="Close">
|
||
</button>
|
||
|
||
<div x-show="$store.modal_engagement_error.title" class="modal-header p-sm mt-sm mb-md">
|
||
<div class="title " x-text="$store.modal_engagement_error.title"></div>
|
||
</div>
|
||
|
||
<div class="modal-content py-md px-lg" x-bind:class="{ 'has-top-border': $store.modal_engagement_error.title }">
|
||
<p x-show="$store.modal_engagement_error.bodyText" class="my-none" x-text="$store.modal_engagement_error.bodyText"></p>
|
||
<p>The likes didn't load as expected. Please refresh the page and try again.</p>
|
||
</div>
|
||
|
||
<div x-show="$store.modal_engagement_error.options.length" class="modal-footer p-sm">
|
||
<template x-for="option in $store.modal_engagement_error.options">
|
||
<button x-show="option.canDisplay" x-text="option.text"
|
||
type="button"
|
||
x-bind:id="'button_modal_engagement_error_' + option.index"
|
||
x-bind:class="option.classList"
|
||
x-on:click="option.onClick"
|
||
x-bind:disabled="option.isDisabled"
|
||
></button>
|
||
</template>
|
||
</div>
|
||
</div>
|
||
</div>
|
||
</div>
|
||
|
||
<script>
|
||
document.addEventListener("alpine:init", () => {
|
||
Alpine.store("modal_engagement_error", {
|
||
_open: false,
|
||
title: "Oops! Something Went Wrong",
|
||
bodyText: null,
|
||
options: [{"action":"dismiss","text":"Close"}],
|
||
closeable: true,
|
||
dismissible: true,
|
||
open(data) {
|
||
if (data) {
|
||
if (data.title) {
|
||
this.title = data.title;
|
||
}
|
||
if (data.bodyText) {
|
||
this.bodyText = data.bodyText;
|
||
}
|
||
if (data.options) {
|
||
this.options = data.options;
|
||
}
|
||
if (data.dismissAfterMs) {
|
||
setTimeout(() => this._open = false, data.dismissAfterMs);
|
||
}
|
||
}
|
||
this.updateOptions();
|
||
this._open = true;
|
||
},
|
||
close() {
|
||
// Manually click the buttons in which should run on dismiss.
|
||
// This is to keep the context. Calling this[option.action]() will not work.
|
||
for (let option of this.options) {
|
||
if (option.runOnDismiss) {
|
||
const element = document.querySelector('#button_modal_engagement_error_' + option.index);
|
||
element.click();
|
||
}
|
||
}
|
||
this._open = false;
|
||
},
|
||
updateOptions() {
|
||
const btnStyle = this.options.length === 2 ? ' btn-default' : '';
|
||
this.options = this.options.map((o, idx) => ({
|
||
...o,
|
||
index: idx,
|
||
classList: o.classList ? o.classList : (idx === 0 ? "btn btn-primary hov-brighten" : "btn hov-underline" + btnStyle),
|
||
onClick: function() {
|
||
if (o.action !== "dismiss") {
|
||
this[o.action]();
|
||
}
|
||
this.$store["modal_engagement_error"].close();
|
||
},
|
||
isDisabled: function() {
|
||
return Object.hasOwn(o, 'disabled') && this[o.disabled]();
|
||
},
|
||
canDisplay: function() {
|
||
return !Object.hasOwn(o, 'condition') || this[o.condition]();
|
||
}
|
||
}));
|
||
},
|
||
init() {
|
||
this.updateOptions();
|
||
}
|
||
});
|
||
});
|
||
</script>
|
||
|
||
<link rel="stylesheet" media="all" href="https://dz2cdn1.dzone.com/themes/dz20/ftl/footer/styles.css">
|
||
|
||
<div id="ftl-footer">
|
||
<div class="container-fluid footerOuter" style="padding-bottom: 90px;">
|
||
<div class="row">
|
||
<div class="col-md-12">
|
||
<div class="container">
|
||
<div class="row footer">
|
||
<div class="col-md-12 footerWidget">
|
||
<div class="row footerContainer footer">
|
||
<div class="left col-xs-12 col-sm-7">
|
||
<div class="col-xs-12 social-media-icons footer-mobile">
|
||
<ul class="icons-only">
|
||
<li class="rss-icon" id="rss-footer-1">
|
||
<a href="/pages/feeds" target="_blank" rel="noreferrer noopener">
|
||
<svg role="img" viewBox="0 0 24 24" class="w-4 h-4 mt-1.75 fill-current" aria-label="Follow our RSS feeds">
|
||
<title>RSS</title>
|
||
<path d="M19.199 24C19.199 13.467 10.533 4.8 0 4.8V0c13.165 0 24 10.835 24 24h-4.801zM3.291 17.415c1.814 0 3.293 1.479 3.293 3.295 0 1.813-1.485 3.29-3.301 3.29C1.47 24 0 22.526 0 20.71s1.475-3.294 3.291-3.295zM15.909 24h-4.665c0-6.169-5.075-11.245-11.244-11.245V8.09c8.727 0 15.909 7.184 15.909 15.91z"></path>
|
||
</svg>
|
||
</a>
|
||
</li>
|
||
<li class="twitter-icon">
|
||
<a href="https://twitter.com/DZoneInc" target="_blank" rel="noreferrer noopener">
|
||
<svg role="img" viewBox="0 0 24 24" aria-label="Follow us on X">
|
||
<title>X</title>
|
||
<path d="M14.234 10.162 22.977 0h-2.072l-7.591 8.824L7.251 0H.258l9.168 13.343L.258 24H2.33l8.016-9.318L16.749 24h6.993zm-2.837 3.299-.929-1.329L3.076 1.56h3.182l5.965 8.532.929 1.329 7.754 11.09h-3.182z"></path>
|
||
</svg>
|
||
</a>
|
||
</li>
|
||
<li class="facebook-icon">
|
||
<a href="https://www.facebook.com/DZoneInc" target="_blank" rel="noreferrer noopener">
|
||
<svg role="img" viewBox="0 0 24 24" aria-label="Follow us on Facebook">
|
||
<title>Facebook</title>
|
||
<path d="M9.101 23.691v-7.98H6.627v-3.667h2.474v-1.58c0-4.085 1.848-5.978 5.858-5.978.401 0 .955.042 1.468.103a8.68 8.68 0 0 1 1.141.195v3.325a8.623 8.623 0 0 0-.653-.036 26.805 26.805 0 0 0-.733-.009c-.707 0-1.259.096-1.675.309a1.686 1.686 0 0 0-.679.622c-.258.42-.374.995-.374 1.752v1.297h3.919l-.386 2.103-.287 1.564h-3.246v8.245C19.396 23.238 24 18.179 24 12.044c0-6.627-5.373-12-12-12s-12 5.373-12 12c0 5.628 3.874 10.35 9.101 11.647Z"></path>
|
||
</svg>
|
||
</a>
|
||
</li>
|
||
<li class="linkedin-icon">
|
||
<a href="https://www.linkedin.com/company/dzone/" target="_blank"
|
||
rel="noreferrer noopener">
|
||
<svg viewBox="0 0 24 25" fill="none" aria-label="Follow us on LinkedIn">
|
||
<path d="M6.20062 21.2143H1.84688V7.194H6.20062V21.2143ZM4.02141 5.2815C2.62922 5.2815 1.5 4.12838 1.5 2.73619C1.5 2.06747 1.76565 1.42614 2.2385 0.953285C2.71136 0.48043 3.35269 0.214783 4.02141 0.214783C4.69012 0.214783 5.33145 0.48043 5.80431 0.953285C6.27716 1.42614 6.54281 2.06747 6.54281 2.73619C6.54281 4.12838 5.413 5.2815 4.02141 5.2815ZM22.4953 21.2143H18.1509V14.3893C18.1509 12.7628 18.1181 10.6768 15.8873 10.6768C13.6237 10.6768 13.2769 12.444 13.2769 14.2721V21.2143H8.92781V7.194H13.1034V9.1065H13.1644C13.7456 8.00494 15.1655 6.84244 17.2838 6.84244C21.69 6.84244 22.5 9.744 22.5 13.5128V21.2143H22.4953Z" fill="currentColor"></path>
|
||
</svg>
|
||
</a>
|
||
</li>
|
||
</ul>
|
||
</div>
|
||
|
||
<div class="top-section col-xs-12">
|
||
<div class="col-xs-12 col-sm-6">
|
||
<p class="section-header">ABOUT US</p>
|
||
<ul class="link-group">
|
||
<li><a href="/pages/about" rel="noreferrer noopener">About DZone</a></li>
|
||
<li><a href="/cdn-cgi/l/email-protection#ef9c9a9f9f809d9baf8b9580818ac18c8082" rel="noreferrer noopener">Support and feedback</a></li>
|
||
<li><a href="/pages/dzone-community-research">Community research</a></li>
|
||
</ul>
|
||
</div>
|
||
<div class="col-xs-12 col-sm-6">
|
||
<p class="section-header">ADVERTISE</p>
|
||
<ul class="link-group">
|
||
<li><a href="https://advertise.dzone.com" target="_blank" rel="noreferrer noopener">Advertise with DZone</a></li>
|
||
</ul>
|
||
</div>
|
||
</div>
|
||
|
||
<div class="bottom-section col-xs-12">
|
||
<div class="col-xs-12 col-sm-6">
|
||
<p class="section-header">CONTRIBUTE ON DZONE</p>
|
||
<ul class="bottom-top-list link-group">
|
||
<li><a href="/articles/dzones-article-submission-guidelines">Article Submission Guidelines</a></li>
|
||
<li><a href="/pages/contribute" rel="noreferrer noopener">Become a Contributor</a></li>
|
||
<li><a href="/pages/core" rel="noreferrer noopener">Core Program</a></li>
|
||
<li><a href="/writers-zone" rel="noreferrer noopener">Visit the Writers' Zone</a></li>
|
||
</ul>
|
||
|
||
<p class="section-header">LEGAL</p>
|
||
<ul class="link-group">
|
||
<li><a href="https://technologyadvice.com/terms-conditions/" target="_blank" rel="noreferrer noopener">Terms of Service</a></li>
|
||
<li><a href="https://technologyadvice.com/privacy-policy/" target="_blank" rel="noreferrer noopener">Privacy Policy</a></li>
|
||
</ul>
|
||
</div>
|
||
<div class="col-xs-12 col-sm-6">
|
||
<p class="section-header">CONTACT US</p>
|
||
<ul class="link-group">
|
||
<li>3343 Perimeter Hill Drive</li>
|
||
<li>Suite 215</li>
|
||
<li>Nashville, TN 37211</li>
|
||
<li><a href="/cdn-cgi/l/email-protection#e1929491918e9395a1859b8e8f84cf828e8c" rel="noreferrer noopener"><span class="__cf_email__" data-cfemail="14676164647b666054706e7b7a713a777b79">[email protected]</span></a></li>
|
||
</ul>
|
||
</div>
|
||
</div>
|
||
</div>
|
||
|
||
<div class="right col-xs-12 col-sm-5">
|
||
|
||
<p class="connect-text">Let's be friends:</p>
|
||
<div class="col-xs-12 social-media-icons footer-wide">
|
||
<ul class="icons-only">
|
||
<li class="rss-icon" id="rss-footer-1">
|
||
<a href="/pages/feeds" target="_blank" rel="noreferrer noopener">
|
||
<svg role="img" viewBox="0 0 24 24" aria-label="Follow our RSS feeds">
|
||
<title>RSS</title>
|
||
<path d="M19.199 24C19.199 13.467 10.533 4.8 0 4.8V0c13.165 0 24 10.835 24 24h-4.801zM3.291 17.415c1.814 0 3.293 1.479 3.293 3.295 0 1.813-1.485 3.29-3.301 3.29C1.47 24 0 22.526 0 20.71s1.475-3.294 3.291-3.295zM15.909 24h-4.665c0-6.169-5.075-11.245-11.244-11.245V8.09c8.727 0 15.909 7.184 15.909 15.91z"></path>
|
||
</svg>
|
||
</a>
|
||
</li>
|
||
<li class="twitter-icon">
|
||
<a href="https://twitter.com/DZoneInc" target="_blank" rel="noreferrer noopener">
|
||
<svg role="img" viewBox="0 0 24 24" aria-label="Follow us on X">
|
||
<title>X</title>
|
||
<path d="M14.234 10.162 22.977 0h-2.072l-7.591 8.824L7.251 0H.258l9.168 13.343L.258 24H2.33l8.016-9.318L16.749 24h6.993zm-2.837 3.299-.929-1.329L3.076 1.56h3.182l5.965 8.532.929 1.329 7.754 11.09h-3.182z"></path>
|
||
</svg>
|
||
</a>
|
||
</li>
|
||
<li class="facebook-icon">
|
||
<a href="https://www.facebook.com/DZoneInc" target="_blank" rel="noreferrer noopener">
|
||
<svg role="img" viewBox="0 0 24 24" aria-label="Follow us on Facebook">
|
||
<title>Facebook</title>
|
||
<path d="M9.101 23.691v-7.98H6.627v-3.667h2.474v-1.58c0-4.085 1.848-5.978 5.858-5.978.401 0 .955.042 1.468.103a8.68 8.68 0 0 1 1.141.195v3.325a8.623 8.623 0 0 0-.653-.036 26.805 26.805 0 0 0-.733-.009c-.707 0-1.259.096-1.675.309a1.686 1.686 0 0 0-.679.622c-.258.42-.374.995-.374 1.752v1.297h3.919l-.386 2.103-.287 1.564h-3.246v8.245C19.396 23.238 24 18.179 24 12.044c0-6.627-5.373-12-12-12s-12 5.373-12 12c0 5.628 3.874 10.35 9.101 11.647Z"></path>
|
||
</svg>
|
||
</a>
|
||
</li>
|
||
<li class="linkedin-icon">
|
||
<a href="https://www.linkedin.com/company/dzone/" target="_blank"
|
||
rel="noreferrer noopener">
|
||
<svg viewBox="0 0 24 25" fill="none" aria-label="Follow us on LinkedIn">
|
||
<path d="M6.20062 21.2143H1.84688V7.194H6.20062V21.2143ZM4.02141 5.2815C2.62922 5.2815 1.5 4.12838 1.5 2.73619C1.5 2.06747 1.76565 1.42614 2.2385 0.953285C2.71136 0.48043 3.35269 0.214783 4.02141 0.214783C4.69012 0.214783 5.33145 0.48043 5.80431 0.953285C6.27716 1.42614 6.54281 2.06747 6.54281 2.73619C6.54281 4.12838 5.413 5.2815 4.02141 5.2815ZM22.4953 21.2143H18.1509V14.3893C18.1509 12.7628 18.1181 10.6768 15.8873 10.6768C13.6237 10.6768 13.2769 12.444 13.2769 14.2721V21.2143H8.92781V7.194H13.1034V9.1065H13.1644C13.7456 8.00494 15.1655 6.84244 17.2838 6.84244C21.69 6.84244 22.5 9.744 22.5 13.5128V21.2143H22.4953Z" fill="currentColor"></path>
|
||
</svg>
|
||
</a>
|
||
</li>
|
||
</ul>
|
||
</div>
|
||
</div>
|
||
</div>
|
||
</div>
|
||
</div>
|
||
</div>
|
||
</div>
|
||
</div>
|
||
</div>
|
||
</div>
|
||
<script data-cfasync="false" src="/cdn-cgi/scripts/5c5dd728/cloudflare-static/email-decode.min.js"></script><script>
|
||
const articleId = 2647173;
|
||
const likes = 5;
|
||
const assetDomain = 'https://dz2cdn1.dzone.com';
|
||
const codemirrorVars = {
|
||
modeURI: 'https://dz2cdn1.dzone.com/themes/dz20/lib/codemirror/mode/',
|
||
requiredScripts: [
|
||
'https://dz2cdn1.dzone.com/themes/dz20/lib/codemirror/lib/codemirror.js',
|
||
'https://dz2cdn1.dzone.com/themes/dz20/lib/codemirror/addon/mode/overlay.js',
|
||
'https://dz2cdn1.dzone.com/themes/dz20/lib/codemirror/addon/mode/multiplex.js',
|
||
'https://dz2cdn1.dzone.com/themes/dz20/lib/codemirror/mode/meta.js'
|
||
]
|
||
};
|
||
|
||
const gptTags = {
|
||
'zone': 'Big Data',
|
||
'topicTag': 'kafka,semantics,application,Transaction log',
|
||
'company': '',
|
||
'siteSection': 'Zones',
|
||
'articleCategory': 'tutorial',
|
||
'nodeID': '2647173',
|
||
'authorID': '3356344',
|
||
'publishYear': '2019',
|
||
'publishMonth': '01',
|
||
'jobRole': '',
|
||
'companySize': '',
|
||
'env': 'prod'
|
||
};
|
||
|
||
const minCommentChar = 10;
|
||
</script>
|
||
<script async>const width = window.innerWidth;
|
||
|
||
const metadata = {
|
||
'top': {
|
||
'position': 'top',
|
||
'slot': 'dz2_article_billboard_new',
|
||
},
|
||
'sponsorLogo': {
|
||
'position': 'zoneHomepage',
|
||
'slot': 'dz2_homepage_sponsor_logo',
|
||
'refreshable': false
|
||
},
|
||
'sidebar1': {
|
||
'position': 'sidebar',
|
||
'slot': 'dz2_article_halfpage_new',
|
||
'minWidthToShow': 1024
|
||
},
|
||
'topBumper': {
|
||
'position': 'top',
|
||
'slot': 'dz2_bumper_text_ad',
|
||
'minWidthToShow': 1024
|
||
},
|
||
'bottomBumper': {
|
||
'position': 'bottom',
|
||
'slot': 'dz2_bumper_text_ad',
|
||
'minWidthToShow': 1024
|
||
},
|
||
'bottom': {
|
||
'position': 'bottom',
|
||
'slot': 'dz2_article_bottom',
|
||
},
|
||
'bottomStickyFooter': {
|
||
'position': 'sticky',
|
||
'slot': 'dz2_sticky_footer_leaderboard',
|
||
},
|
||
'partner': {
|
||
'slot': 'dz2_partner_resource_link',
|
||
},
|
||
'branded': {
|
||
'slot': 'dz2_branded_content',
|
||
'refreshable': false
|
||
},
|
||
'topicBillboard': {
|
||
'position': ['top', 'zoneHomepage'],
|
||
'slot': 'dz2_topic_billboard',
|
||
},
|
||
'listPageSidebar': {
|
||
'position': 'sidebar',
|
||
'slot': 'dz2_list_page_sidebar',
|
||
'minWidthToShow': 1024
|
||
},
|
||
'topListPageLeaderboard2': {
|
||
'position': ['top', 'zoneList'],
|
||
'slot': 'dz2_list_page_leaderboard_2',
|
||
},
|
||
'bottomListPageLeaderboard2': {
|
||
'position': ['bottom', 'zoneList'],
|
||
'slot': 'dz2_list_page_leaderboard_2',
|
||
},
|
||
'homepageLeaderboard': {
|
||
'position': 'top',
|
||
'slot': 'dz2_homepage_leaderboard',
|
||
},
|
||
'homepageLeaderboard2': {
|
||
'position': 'bottom',
|
||
'slot': 'dz2_homepage_leaderboard_2',
|
||
},
|
||
'skybox': {
|
||
'position': 'above nav',
|
||
'slot': 'dz_skybox',
|
||
'refreshable': false
|
||
},
|
||
'inline': {
|
||
'position': 'inline',
|
||
'slot': 'dz2_inline-article-display',
|
||
}
|
||
};
|
||
|
||
var campaign = new URLSearchParams(window.location.search).get("adTargeting_campaign");
|
||
|
||
window.googletag = window.googletag || { cmd: [] };
|
||
|
||
if (campaign) {
|
||
window.googletag.cmd.push(function() {
|
||
window.googletag.setConfig({ targeting: { campaign }});
|
||
});
|
||
}
|
||
|
||
let lastHeader = null;
|
||
|
||
const topContainer = document.querySelector('#top-bumper-container');
|
||
const bottomContainer = document.querySelector('#bottom-bumper-container');
|
||
|
||
function GAM_getPersistentValue(key) {
|
||
const stored = JSON.parse(localStorage.getItem(key));
|
||
|
||
if (!stored) {
|
||
return null;
|
||
}
|
||
|
||
const { value, expiration } = stored;
|
||
|
||
if (expiration && Date.now() >= expiration) {
|
||
localStorage.removeItem(key);
|
||
return null;
|
||
}
|
||
|
||
return value;
|
||
}
|
||
|
||
function GAM_setPersistentValue(key, value, expiration) {
|
||
// 5 minutes from now
|
||
if (!expiration) {
|
||
expiration = Date.now() + 300000;
|
||
}
|
||
|
||
const storedValue = JSON.stringify({
|
||
value: value,
|
||
expiration: expiration
|
||
});
|
||
|
||
localStorage.setItem(key, storedValue);
|
||
|
||
return value;
|
||
}
|
||
|
||
function GAM_synchronousRequest(params) {
|
||
const xhr = new XMLHttpRequest();
|
||
xhr.open('GET', params.url, false);
|
||
xhr.setRequestHeader("Content-Type", "application/json");
|
||
|
||
if (typeof params.auth_header !== "undefined") {
|
||
xhr.setRequestHeader("Authorization", params.auth_header);
|
||
}
|
||
|
||
xhr.send(null);
|
||
if (xhr.status === 200) {
|
||
return xhr.responseText;
|
||
} else {
|
||
throw new Error('Request failed: ' + xhr.statusText);
|
||
}
|
||
}
|
||
|
||
function GAM_fetch_data(params) {
|
||
let stored_data = GAM_getPersistentValue(params.storage_key);
|
||
|
||
if (stored_data === null) {
|
||
try {
|
||
const response = GAM_synchronousRequest(params);
|
||
const data = JSON.parse(response);
|
||
|
||
// Store and expire after 30 minutes
|
||
return GAM_setPersistentValue(params.storage_key, data, Date.now() + 1800000);
|
||
} catch (error) {
|
||
console.error('Could not get ' + params.storage_key + ' data: ' + error);
|
||
return null;
|
||
}
|
||
} else {
|
||
return stored_data;
|
||
}
|
||
}
|
||
|
||
function GAM_setUpSixSenseTargeting() {
|
||
let meData = GAM_fetch_data({
|
||
url: "https://link.technologyadvice.com/_me",
|
||
storage_key: "ta_me_data"
|
||
});
|
||
let sixSenseData = GAM_fetch_data({
|
||
url: "https://epsilon.6sense.com/v3/company/details",
|
||
auth_header: "Token d20a1b0e892442270cbc4cb6801c0160d28af04c",
|
||
storage_key: "ta_6s_data"
|
||
});
|
||
|
||
function meDataIncludes(i) {
|
||
return meData.tags.includes(i);
|
||
}
|
||
|
||
if (typeof meData !== "undefined" && meData !== null) {
|
||
window.googletag.pubads().setTargeting("visitor_id", meData.vid);
|
||
window.googletag.pubads().setTargeting("user_agent", meData.user_agent);
|
||
|
||
var tags_mapping = {
|
||
"is_datacenter": ["site.is-datacenter"],
|
||
"is_suspected_bot": ["site.suspected-bad-bot", "site.bad-bot"],
|
||
"is_ta_user": ["site.is-ta-user"],
|
||
"is_crawler": ["site.user-agent-blocked"],
|
||
"is_ad_blocked": ["site.is-ad-blocked"],
|
||
};
|
||
|
||
for (var key in tags_mapping) {
|
||
if (tags_mapping[key].some(meDataIncludes)) {
|
||
window.googletag.pubads().setTargeting(key, 'true');
|
||
}
|
||
}
|
||
}
|
||
|
||
if (typeof sixSenseData !== "undefined" && sixSenseData !== null) {
|
||
var segment_ids = [];
|
||
if (sixSenseData.segments && sixSenseData.segments.ids && sixSenseData.segments.ids.length) {
|
||
sixSenseData.segments.ids.forEach(function (v) {
|
||
segment_ids.push(v.toString());
|
||
});
|
||
}
|
||
if (typeof segment_ids !== "undefined" && segment_ids.length > 0) {
|
||
window.googletag.pubads().setTargeting("segment_ids_6si", segment_ids);
|
||
}
|
||
}
|
||
}
|
||
|
||
if (width >= 1024 && (topContainer || bottomContainer)) {
|
||
// Dynamically create bumper ad slots for non-mobile devices.
|
||
// Prevents ugly dividers being rendered on empty ad slots (mobile)
|
||
const topBumper = document.createElement('div');
|
||
topBumper.id = 'div-gpt-ad-1435246566686-3';
|
||
topBumper.classList.add('article-bumper', 'article-bumper-top', 'dz2_bumper_text_ad');
|
||
topBumper.setAttribute('data-gpt-slot', 'topBumper');
|
||
|
||
topContainer.appendChild(topBumper);
|
||
|
||
const bottomBumper = document.createElement('div');
|
||
bottomBumper.id = 'div-gpt-ad-1435246566686-4';
|
||
bottomBumper.classList.add('article-bumper', 'article-bumper-bottom', 'dz2_bumper_text_ad');
|
||
bottomBumper.setAttribute('data-gpt-slot', 'bottomBumper');
|
||
|
||
bottomContainer.appendChild(bottomBumper);
|
||
}
|
||
|
||
if (gptTags.zone) {
|
||
gptTags.zone = gptTags.zone.replaceAll(/[\s/]/g, '_')
|
||
.replaceAll(/[^a-zA-Z0-9_]/g, '')
|
||
.toLowerCase();
|
||
}
|
||
|
||
makeAds();
|
||
|
||
function handleSkybox() {
|
||
const skybox = document.querySelector('div.skybox');
|
||
if (skybox) {
|
||
document.body.classList.add('skybox-auto-collapse');
|
||
// observe classlist changes for offsetting sticky ads
|
||
const observer = new MutationObserver((mutations) => {
|
||
mutations.forEach((mutation) => {
|
||
if (mutation.type === 'attributes' && mutation.attributeName === 'class') {
|
||
let offset = 0;
|
||
if (!document.body.classList.contains('skybox-closed') && (
|
||
document.body.classList.contains('ccad-skybox-manualcollapse')
|
||
|| document.body.classList.contains('ccad-skybox-manualexpand')
|
||
)) {
|
||
offset = skybox.getBoundingClientRect().height;
|
||
}
|
||
let eligibleAds = [
|
||
{ element: document.querySelector('.content-right-images'), offset: 108 },
|
||
{ element: document.querySelector('.trending-sidebar'), offset: 88 },
|
||
{ element: document.querySelector('.trending'), offset: 88 }
|
||
];
|
||
for (let ad of eligibleAds) {
|
||
if (ad.element) {
|
||
ad.element.style.top = (ad.offset + offset) + 'px';
|
||
}
|
||
}
|
||
}
|
||
});
|
||
});
|
||
observer.observe(document.body, { attributes: true });
|
||
}
|
||
}
|
||
|
||
function isHeaderEligible(header) {
|
||
const range = document.createRange();
|
||
range.setStartAfter(lastHeader);
|
||
range.setEndBefore(header);
|
||
|
||
return range.toString().trim().length >= 600;
|
||
}
|
||
|
||
function placeInlineAds() {
|
||
const excludedContent = document.querySelectorAll('#ftl-article.branded-content, #ftl-article.sponsored');
|
||
|
||
if (excludedContent.length > 0) {
|
||
return;
|
||
}
|
||
|
||
const headers = Array.from(document.querySelectorAll('.content-html h2')).splice(1);
|
||
|
||
let globalIndex = 12;
|
||
|
||
for (let i = 0; i < headers.length; i++) {
|
||
if (!lastHeader || isHeaderEligible(headers[i])) {
|
||
const element = document.createElement('div');
|
||
element.id = 'div-gpt-ad-1435246566686-' + globalIndex;
|
||
element.classList.add('inline-display', 'dz2_inline-article-display');
|
||
element.setAttribute('data-gpt-slot', 'inline');
|
||
headers[i].before(element);
|
||
lastHeader = element;
|
||
globalIndex++;
|
||
}
|
||
}
|
||
}
|
||
|
||
function makeAds() {
|
||
handleSkybox();
|
||
placeInlineAds();
|
||
|
||
const script = document.createElement('script');
|
||
script.src = 'https://i6ByW9Zmz4ncxhHkb.ay.delivery/manager/i6ByW9Zmz4ncxhHkb';
|
||
script.type = 'text/javascript';
|
||
script.referrerPolicy = 'no-referrer-when-downgrade';
|
||
|
||
document.head.appendChild(script);
|
||
|
||
window.googletag.cmd.push(function() {
|
||
const containers = document.querySelectorAll('div[data-gpt-slot]');
|
||
|
||
for (let container of containers) {
|
||
const div = container.getAttribute('data-gpt-slot');
|
||
const meta = metadata[div];
|
||
|
||
if (meta.minWidthToShow && width < meta.minWidthToShow) {
|
||
continue;
|
||
}
|
||
|
||
window.googletag.pubads().setTargeting('hostname', window.location.hostname);
|
||
|
||
Object.keys(gptTags).forEach(function(key) {
|
||
window.googletag.pubads().setTargeting(key, gptTags[key]);
|
||
});
|
||
|
||
window.googletag.pubads().addEventListener('slotRenderEnded', (event) => {
|
||
window.requestAnimationFrame(() => {
|
||
var slotId = event.slot.getSlotElementId();
|
||
|
||
if (!slotId.includes('__ayManagerEnv__')) {
|
||
return;
|
||
}
|
||
|
||
var className = slotId.split('__ayManagerEnv__')[0];
|
||
var slotName = className.replace('dz2_', '').replace('dz_', '').replace(/_\d+$/, '');
|
||
var unitName = meta.slot.replace('dz2_', '').replace('dz_', '').replace(/_\d+$/, '');
|
||
|
||
if (slotName !== unitName) {
|
||
return;
|
||
}
|
||
|
||
var elem = document.getElementById(slotId);
|
||
|
||
if (!elem) {
|
||
console.warn('Ad element missing', slotId);
|
||
return;
|
||
}
|
||
|
||
// Ad unit did not fill, collapse slot
|
||
if (event.isEmpty && elem.parentElement) {
|
||
elem.parentElement.style.display = 'none';
|
||
}
|
||
});
|
||
});
|
||
}
|
||
|
||
GAM_setUpSixSenseTargeting();
|
||
});
|
||
}
|
||
</script>
|
||
<script async>// InMobi Choice. Consent Manager Tag v3.0 (for TCF 2.2)
|
||
!function(){var e=window.location.hostname,t=document.createElement("script"),n=document.getElementsByTagName("script")[0],a="https://cmp.inmobi.com".concat("/choice/","vPn77x7pBG57Y","/","dzone.com","/choice.js?tag_version=V3"),p=0;t.async=!0,t.type="text/javascript",t.src=a,n.parentNode.insertBefore(t,n),function(){for(var e,t="__tcfapiLocator",n=[],a=window;a;){try{if(a.frames[t]){e=a;break}}catch(e){}if(a===window.top)break;a=a.parent}e||(!function e(){var n=a.document,p=!!a.frames[t];if(!p)if(n.body){var s=n.createElement("iframe");s.style.cssText="display:none",s.name=t,n.body.appendChild(s)}else setTimeout(e,5);return!p}(),a.__tcfapi=function(){var e,t=arguments;if(!t.length)return n;if("setGdprApplies"===t[0])t.length>3&&2===t[2]&&"boolean"==typeof t[3]&&(e=t[3],"function"==typeof t[2]&&t[2]("set",!0));else if("ping"===t[0]){var a={gdprApplies:e,cmpLoaded:!1,cmpStatus:"stub"};"function"==typeof t[2]&&t[2](a)}else"init"===t[0]&&"object"==typeof t[3]&&(t[3]=Object.assign(t[3],{tag_version:"V3"})),n.push(t)},a.addEventListener("message",(function(e){var t="string"==typeof e.data,n={};try{n=t?JSON.parse(e.data):e.data}catch(e){}var a=n.__tcfapiCall;a&&window.__tcfapi(a.command,a.version,(function(n,p){var s={__tcfapiReturn:{returnValue:n,success:p,callId:a.callId}};t&&(s=JSON.stringify(s)),e&&e.source&&e.source.postMessage&&e.source.postMessage(s,"*")}),a.parameter)}),!1))}(),function(){const e=["2:tcfeuv2","6:uspv1","7:usnatv1","8:usca","9:usvav1","10:uscov1","11:usutv1","12:usctv1"];window.__gpp_addFrame=function(e){if(!window.frames[e])if(document.body){var t=document.createElement("iframe");t.style.cssText="display:none",t.name=e,document.body.appendChild(t)}else window.setTimeout(window.__gpp_addFrame,10,e)},window.__gpp_stub=function(){var t=arguments;if(__gpp.queue=__gpp.queue||[],__gpp.events=__gpp.events||[],!t.length||1==t.length&&"queue"==t[0])return __gpp.queue;if(1==t.length&&"events"==t[0])return __gpp.events;var n=t[0],a=t.length>1?t[1]:null,p=t.length>2?t[2]:null;if("ping"===n)a({gppVersion:"1.1",cmpStatus:"stub",cmpDisplayStatus:"hidden",signalStatus:"not ready",supportedAPIs:e,cmpId:10,sectionList:[],applicableSections:[-1],gppString:"",parsedSections:{}},!0);else if("addEventListener"===n){"lastId"in __gpp||(__gpp.lastId=0),__gpp.lastId++;var s=__gpp.lastId;__gpp.events.push({id:s,callback:a,parameter:p}),a({eventName:"listenerRegistered",listenerId:s,data:!0,pingData:{gppVersion:"1.1",cmpStatus:"stub",cmpDisplayStatus:"hidden",signalStatus:"not ready",supportedAPIs:e,cmpId:10,sectionList:[],applicableSections:[-1],gppString:"",parsedSections:{}}},!0)}else if("removeEventListener"===n){for(var i=!1,o=0;o<__gpp.events.length;o++)if(__gpp.events[o].id==p){__gpp.events.splice(o,1),i=!0;break}a({eventName:"listenerRemoved",listenerId:p,data:i,pingData:{gppVersion:"1.1",cmpStatus:"stub",cmpDisplayStatus:"hidden",signalStatus:"not ready",supportedAPIs:e,cmpId:10,sectionList:[],applicableSections:[-1],gppString:"",parsedSections:{}}},!0)}else"hasSection"===n?a(!1,!0):"getSection"===n||"getField"===n?a(null,!0):__gpp.queue.push([].slice.apply(t))},window.__gpp_msghandler=function(e){var t="string"==typeof e.data;try{var n=t?JSON.parse(e.data):e.data}catch(e){n=null}if("object"==typeof n&&null!==n&&"__gppCall"in n){var a=n.__gppCall;window.__gpp(a.command,(function(n,p){var s={__gppReturn:{returnValue:n,success:p,callId:a.callId}};e.source.postMessage(t?JSON.stringify(s):s,"*")}),"parameter"in a?a.parameter:null,"version"in a?a.version:"1.1")}},"__gpp"in window&&"function"==typeof window.__gpp||(window.__gpp=window.__gpp_stub,window.addEventListener("message",window.__gpp_msghandler,!1),window.__gpp_addFrame("__gppLocator"))}();var s=function(){var e=arguments;typeof window.__uspapi!==s&&setTimeout((function(){void 0!==window.__uspapi&&window.__uspapi.apply(window.__uspapi,e)}),500)};if(void 0===window.__uspapi){window.__uspapi=s;var i=setInterval((function(){p++,window.__uspapi===s&&p<3?console.warn("USP is not accessible"):clearInterval(i)}),6e3)}}();
|
||
</script>
|
||
|
||
<script async>
|
||
(function(w, d, s, l, i) {
|
||
w[l] = w[l] || [];
|
||
w[l].push({'gtm.start': new Date().getTime(), event: 'gtm.js'});
|
||
var f = d.getElementsByTagName(s)[0], j = d.createElement(s), dl = l != 'dataLayer' ? '&l=' + l : '';
|
||
j.async = true;
|
||
j.src = 'https://www.googletagmanager.com/gtm.js?id=' + i + dl;
|
||
f.parentNode.insertBefore(j,f);
|
||
})(window, document, 'script', 'dataLayer', 'GTM-K25QL22');
|
||
</script>
|
||
|
||
<script>
|
||
window.ga=window.ga||function(){(ga.q=ga.q||[]).push(arguments)};ga.l=+new Date;
|
||
ga('create', 'UA-410289-1', 'auto');
|
||
ga('require', 'linkid', 'linkid.js');
|
||
ga('require', 'GTM-TSD9TZP');
|
||
ga('set', 'siteSpeedSampleRate', 25);
|
||
</script>
|
||
<script async src="https://www.google-analytics.com/analytics.js"></script>
|
||
<script async>var analytics = {
|
||
'dimension1': 'Big Data',
|
||
'dimension2': 'article/tutorial',
|
||
'dimension3': '2019-01-01',
|
||
'dimension4': '0',
|
||
'dimension5': '',
|
||
'dimension7': 'kafka, semantics, application, Transaction log',
|
||
'dimension8': 'rahulag',
|
||
'dimension9': 'undefined',
|
||
'dimension10': 'TCS'
|
||
};
|
||
|
||
if (window.ga) {
|
||
Object.keys(analytics).forEach(function(key) {
|
||
window.ga('set', key, analytics[key]);
|
||
});
|
||
|
||
window.ga('send', 'pageview');
|
||
}</script>
|
||
|
||
<script src="https://dz2cdn1.dzone.com/themes/dz20/lib/static/jquery/jquery.min.js"></script>
|
||
<script async src="https://dz2cdn1.dzone.com/themes/dz20/lib/static/bootstrap/bootstrap.min.js"></script>
|
||
|
||
<script>
|
||
function loadScript(src) {
|
||
return new Promise(function (resolve, reject) {
|
||
const s = document.createElement('script');
|
||
s.src = src;
|
||
s.onload = resolve;
|
||
s.onerror = reject;
|
||
document.head.appendChild(s);
|
||
});
|
||
}
|
||
|
||
function loadStyle(href) {
|
||
const link = document.createElement('link');
|
||
link.rel = 'stylesheet';
|
||
link.href = href;
|
||
document.head.appendChild(link);
|
||
}
|
||
|
||
function loadScriptsSync(deferred) {
|
||
var p = Promise.resolve();
|
||
for (var i = 0; i < deferred.length; i++) {
|
||
let script = deferred[i];
|
||
p = p.then(function() {
|
||
return loadScript(script);
|
||
});
|
||
}
|
||
return p;
|
||
}
|
||
|
||
function loadStyles() {
|
||
const deferred = [
|
||
'https://dz2cdn1.dzone.com/themes/dz20/lib/codemirror/lib/codemirror.css',
|
||
'https://dz2cdn1.dzone.com/themes/dz20/ftl/comments/styles.css',
|
||
'https://dz2cdn1.dzone.com/themes/dz20/lib/froala3/css/froala_editor.pkgd.min.css',
|
||
'https://dz2cdn1.dzone.com/themes/dz20/lib/froala3/css/themes/gray.min.css',
|
||
'https://dz2cdn1.dzone.com/themes/dz20/ftl/article/mini-profile.css'
|
||
];
|
||
|
||
for (var i = 0; i < deferred.length; i++) {
|
||
loadStyle(deferred[i]);
|
||
}
|
||
}
|
||
|
||
window.addEventListener('load', function(_event) {
|
||
loadStyles();
|
||
|
||
loadScriptsSync([
|
||
'https://dz2cdn1.dzone.com/themes/dz20/lib/lazysizes.min.js',
|
||
'https://dz2cdn1.dzone.com/themes/dz20/ftl/article/codeblocks.js',
|
||
'https://dz2cdn1.dzone.com/themes/dz20/ftl/article/activity-bar.js',
|
||
'https://dz2cdn1.dzone.com/themes/dz20/lib/froala3/js/froala_editor.pkgd.min.js',
|
||
'https://dz2cdn1.dzone.com/themes/dz20/ftl/froala/content.js',
|
||
'https://dz2cdn1.dzone.com/themes/dz20/ftl/comments/content.js',
|
||
'https://dz2cdn1.dzone.com/themes/dz20/ftl/article/content.js'
|
||
]);
|
||
});
|
||
</script>
|
||
</body>
|
||
</html>
|