Lighthouse for Azure Pipelines

This is an Azure DevOps extension that allows you to enhance your Azure Pipelines with a Lighthouse tab. The Lighthouse tab embed one or many HTML reports generated by Google Lighthouse.

The task only requires a target URL to execute Lighthouse against.

If the Lighthouse NPM package is already installed locally or globally on the agent, then the task will use it. Otherwise, it will install the latest version in a temporary folder.

Lighthouse HTML report embed in a tab

You can also specify audit score assertions that can make the pipeline fail based on the audit scores.

For example, the Google Lighthouse audit is-on-https produces a boolean score that will be equal to 1 if the site uses HTTPS. This is an example of a score assertion for this audit:

is-on-https = 1

Which means that you expect the audit is-on-https to have a score equal to 1.

Any audit score generated by Lighthouse is between 0 and 1. You can also use the > (greater than) and the < (lower than) operator to evaluate decimal audit scores. Audit score assertions must be written on separate lines.

Lighthouse task

Installation

Lighthouse for Azure Pipelines can be installed from the Visual Studio Marketplace.

Lighthouse audits that can be used in assertions

The following audits are available for assertions in Lighthouse 10.1.0. They may change with new versions. Execute lighthouse --list-all-audits to discover the available audits for your desired Lighthouse version.

Audit	Type	Description
is-on-https	binary	Uses HTTPS
service-worker	binary	Does not register a service worker that controls page and `start_url`
viewport	binary	Has a `<meta name="viewport">` tag with `width` or `initial-scale`
first-contentful-paint	numeric	First Contentful Paint
largest-contentful-paint	numeric	Largest Contentful Paint
first-meaningful-paint	numeric	First Meaningful Paint
speed-index	numeric	Speed Index
total-blocking-time	numeric	Total Blocking Time
max-potential-fid	numeric	Max Potential First Input Delay
cumulative-layout-shift	numeric	Cumulative Layout Shift
errors-in-console	binary	No browser errors logged to the console
server-response-time	binary	Initial server response time was short
interactive	numeric	Time to Interactive
redirects	numeric	Avoid multiple page redirects
installable-manifest	binary	Web app manifest or service worker do not meet the installability requirements
splash-screen	binary	Is not configured for a custom splash screen
themed-omnibox	binary	Does not set a theme color for the address bar.
maskable-icon	binary	Manifest doesn't have a maskable icon
content-width	binary	Content is sized correctly for the viewport
image-aspect-ratio	binary	Displays images with correct aspect ratio
image-size-responsive	binary	Serves images with appropriate resolution
deprecations	binary	Avoids deprecated APIs
mainthread-work-breakdown	numeric	Minimizes main-thread work
bootup-time	numeric	JavaScript execution time
uses-rel-preconnect	numeric	Preconnect to required origins
font-display	binary	All text remains visible during webfont loads
third-party-summary	binary	Minimize third-party usage
no-unload-listeners	binary	Avoids `unload` event listeners
unsized-images	binary	Image elements have explicit `width` and `height`
valid-source-maps	binary	Page has valid source maps
aria-allowed-attr	binary	`[aria-*]` attributes match their roles
aria-hidden-body	binary	`[aria-hidden="true"]` is not present on the document `<body>`
aria-hidden-focus	binary	`[aria-hidden="true"]` elements contain focusable descendents
aria-valid-attr-value	binary	`[aria-*]` attributes have valid values
aria-valid-attr	binary	`[aria-*]` attributes are valid and not misspelled
button-name	binary	Buttons have an accessible name
color-contrast	binary	Background and foreground colors have a sufficient contrast ratio
document-title	binary	Document has a `<title>` element
duplicate-id-active	binary	`[id]` attributes on active, focusable elements are unique
duplicate-id-aria	binary	ARIA IDs are unique
heading-order	binary	Heading elements appear in a sequentially-descending order
html-has-lang	binary	`<html>` element has a `[lang]` attribute
html-lang-valid	binary	`<html>` element has a valid value for its `[lang]` attribute
image-alt	binary	Image elements have `[alt]` attributes
link-name	binary	Links have a discernible name
list	binary	Lists contain only `<li>` elements and script supporting elements (`<script>` and `<template>`).
listitem	binary	List items (`<li>`) are contained within `<ul>`, `<ol>` or `<menu>` parent elements
meta-viewport	binary	`[user-scalable="no"]` is not used in the `<meta name="viewport">` element and the `[maximum-scale]` attribute is not less than 5.
uses-long-cache-ttl	numeric	Uses efficient cache policy on static assets
total-byte-weight	numeric	Avoids enormous network payloads
offscreen-images	numeric	Defer offscreen images
render-blocking-resources	numeric	Eliminate render-blocking resources
unminified-css	numeric	Minify CSS
unminified-javascript	numeric	Minify JavaScript
unused-css-rules	numeric	Reduce unused CSS
unused-javascript	numeric	Reduce unused JavaScript
modern-image-formats	numeric	Serve images in next-gen formats
uses-optimized-images	numeric	Efficiently encode images
uses-text-compression	numeric	Enable text compression
uses-responsive-images	numeric	Properly size images
efficient-animated-content	numeric	Use video formats for animated content
duplicated-javascript	numeric	Remove duplicate modules in JavaScript bundles
legacy-javascript	numeric	Avoid serving legacy JavaScript to modern browsers
doctype	binary	Page has the HTML doctype
charset	binary	Properly defines charset
dom-size	numeric	Avoids an excessive DOM size
geolocation-on-start	binary	Avoids requesting the geolocation permission on page load
inspector-issues	binary	No issues in the `Issues` panel in Chrome Devtools
no-document-write	binary	Avoids `document.write()`
notification-on-start	binary	Avoids requesting the notification permission on page load
paste-preventing-inputs	binary	Allows users to paste into input fields
uses-http2	numeric	Use HTTP/2
uses-passive-event-listeners	binary	Uses passive listeners to improve scrolling performance
meta-description	binary	Document has a meta description
http-status-code	binary	Page has successful HTTP status code
font-size	binary	Document uses legible font sizes
link-text	binary	Links have descriptive text
crawlable-anchors	binary	Links are crawlable
is-crawlable	binary	Page isn’t blocked from indexing
robots-txt	binary	robots.txt is valid
tap-targets	binary	Tap targets are sized appropriately
hreflang	binary	Document has a valid `hreflang`
plugins	binary	Document avoids plugins
canonical	binary	Document has a valid `rel=canonical`
bf-cache	binary	Page prevented back/forward cache restoration

Build and release process

There are GitHub actions that take care of testing, packaging and publishing the extension.

License

Copyright © 2023, Groupe GSoft Inc. This code is licensed under the Apache License, Version 2.0. You may obtain a copy of this license at https://github.com/gsoft-inc/azure-pipelines-lighthouse/blob/main/LICENSE.