Lighthouse CI

A useful wrapper around Google Lighthouse CLI

Install

$ npm install -g lighthouse-ci

Table of Contents

• Lighthouse CI
  • Install
  • Table of Contents
  • Usage
  • CLI
  • Lighthouse flags
    • Chrome flags
  • Configuration
  • Performance Budget
    • Option 1.
    • Option 2.
    • Option 3.
  • Codechecks
  • Demo App
  • How to
    • Test a page that requires authentication
    • Wait for post-load JavaScript to execute before ending a trace
  • Contributors
  • License

Usage

lighthouse-ci --help

CLI

$ lighthouse-ci --help

  Usage
    $ lighthouse-ci <target-url>

  Example
    $ lighthouse-ci https://example.com
    $ lighthouse-ci https://example.com -s
    $ lighthouse-ci https://example.com --score=75
    $ lighthouse-ci https://example.com --accessibility=90 --seo=80
    $ lighthouse-ci https://example.com --accessibility=90 --seo=80 --report=folder
    $ lighthouse-ci https://example.com --report=folder --config-path=configs.json

  Options
    -s, --silent                  Run Lighthouse without printing report log
    --report=<path>               Generate an HTML report inside a specified folder
    --filename=<filename>         Specify the name of the generated HTML report file (requires --report)
    -json, --jsonReport           Generate JSON report in addition to HTML (requires --report)
    --config-path                 The path to the Lighthouse config JSON (read more here: https://github.com/GoogleChrome/lighthouse/blob/master/docs/configuration.md)
    --budget-path                 The path to the Lighthouse budgets config JSON (read more here: https://developers.google.com/web/tools/lighthouse/audits/budgets)
    --score=<threshold>           Specify a score threshold for the CI to pass
    --performance=<threshold>     Specify a minimal performance score for the CI to pass
    --pwa=<threshold>             Specify a minimal pwa score for the CI to pass
    --accessibility=<threshold>   Specify a minimal accessibility score for the CI to pass
    --best-practice=<threshold>   [DEPRECATED] Use best-practices instead
    --best-practices=<threshold>  Specify a minimal best-practice score for the CI to pass
    --seo=<threshold>             Specify a minimal seo score for the CI to pass
    --budget.<counts|sizes>.<type>    Specify individual budget threshold (if --budget-path not set)
    --chromium-fallback           If no Chrome installations are found download and use Chromium browser instead
    --chromium-force              Always download and use Chromium browser.

Lighthouse flags

In addition to listed lighthouse-ci configuration flags, it is also possible to pass any native lighthouse flags.

To see the full list of available flags, please refer to the official Google Lighthouse documentation.

eg.

# Launches browser, collects artifacts, saves them to disk (in `./test-report/`) and quits
$ lighthouse-ci --gather-mode=test-report https://my.website.com
# skips browser interaction, loads artifacts from disk (in `./test-report/`), runs audits on them, generates report
$ lighthouse-ci --audit-mode=test-report https://my.website.com

Chrome flags

In addition of the lighthouse flags, you can also specify extra chrome flags comma separated.

eg.

$ lighthouse-ci --chrome-flags=--cellular-only,--force-ui-direction=rtl https://my.website.com

eg.

$ lighthouse-ci --emulated-form-factor desktop --seo 92 https://my.website.com

Configuration

Lighthouse CI allows you to pass a custom Lighthouse configuration file. Read Lighthouse Configuration to learn more about the configuration options available.

Just generate your configuration file. For example this config.json

{
  "extends": "lighthouse:default",
  "audits": [
    "user-timings",
    "critical-request-chains"
  ],

  "categories": {
    "performance": {
      "name": "Performance Metrics",
      "description": "Sample description",
      "audits": [
        {"id": "user-timings", "weight": 1},
        {"id": "critical-request-chains", "weight": 1}
      ]
    }
  }
}

Then run Lighthouse CI with the --config-path flag

$ lighthouse-ci https://example.com --report=reports --config-path=config.json

The generated report inside reports folder will follow the custom configuration listed under the config.json file.

Performance Budget

Lighthouse CI allows you to pass a performance budget configuration file (see Lighthouse Budgets). There are several options to pass performance budget configs:

Option 1.

Add configurations to your config.json file like and use instructions above.

{
  "extends": "lighthouse:default",
  "settings": {
    "budgets": [
      {
        "resourceCounts": [
          { "resourceType": "total", "budget": 10 },
          ...
        ],
        "resourceSizes": [
          { "resourceType": "total", "budget": 100 },
          ...
        ]
      }
    ]
  }
}

Option 2.

Generate budget.json with content like:

[
  {
    "resourceCounts": [
      { "resourceType": "total", "budget": 10 },
      ...
    ],
    "resourceSizes": [
      { "resourceType": "total", "budget": 100 },
      ...
    ]
  }
]

Then run Lighthouse CI with the --budget-path flag

$ lighthouse-ci https://example.com --report=reports --budget-path=budget.json

Option 3.

Pass individual parameters via CLI

$ lighthouse-ci https://example.com --report=reports --budget.counts.total=20  --budget.sizes.fonts=100000

Codechecks

You can now easily integrate Lighthouse-CI as part of your automated CI with codechecks.io.

Running Lighthouse-CI with Codechecks

$ npm install --save-dev @codechecks/client @codechecks/lighthouse-keeper

Now, create a codechecks.yml (json is supported as well) file required for codechecks to automatically run against your project.

codechecks.yml:

checks:
  - name: lighthouse-keeper
    options:
      # just provide path to your build
      buildPath: ./build
      # or full url
      # url: https://google.com
  # ...

Read more from the official documentation from https://github.com/codechecks/lighthouse-keeper.

Read more about Codechecks on the official project website

Demo App

This project contains a demo folder where a project as been created for demo purposes only. Once inside the demo folder, if you have Docker installed on your machine, you can simply launch the demo app inside a Docker container with make demo.

If you just want to run the demo locally, make sure to install the node dependencies first with npm install, then run the demo with:

$ npm start

How to

Test a page that requires authentication

By default lighthouse-cli is just creating the report against a specific URL without letting the engineer to interact with the browser. Sometimes, however, the page for which you want to generate the report, requires the user to be authenticated. Depending on the authentication mechanism, you can inject extra header information into the page.

lighthouse-ci https://example.com --extra-headers=./extra-headers.js

Where extra-headers.json contains:

module.exports = {
  Authorization: 'Bearer MyAccessToken',
  Cookie: "user=MySecretCookie;"
};

Wait for post-load JavaScript to execute before ending a trace

Your website might require extra time to load and execute all the JavaScript logic. It is possible to let LightHouse wait for a certain amount of time, before ending a trace, by providing a pauseAfterLoadMs value to a custom configuration file.

eg.

lighthouse-ci https://example.com --config-path ./config.json

Where config.json contains:

{
  "extends": "lighthouse:default",
  "passes": [{
    "recordTrace": true,
    "pauseAfterLoadMs": 5000,
    "networkQuietThresholdMs": 5000
  }]
}

Contributors

Thanks goes to these wonderful people (emoji key):

This project follows the all-contributors specification. Contributions of any kind welcome!

License

MIT

Created with 🦄 by andreasonny83