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Certificate Transparency website.

This website is built as a static site using Hugo. Stylesheets are written in SCSS.


You'll need Hugo 0.60 extended or greater installed on your path. For OSX, brew install hugo should hook you up. The site was developed against Hugo 0.62.

You'll need a Javascript package manger to install PostCSS and other dependencies. npm is recommended (primarily for compatibility with Github Actions).

Running the site locally

npm install

will install the JS dependencies. Once you've done that, you can spin up a local server with

hugo serve

Where content is stored

  • pages are in content/. (.html pages work as Hugo content, as long as you include frontmatter).
    • images specific to pages are in subdirectories of those content directories.
  • community-page entries are in content/events. They work as a headless page bundle. More documentation on how to update this is in
  • step-by-step entries are in content/stepbystep. They work as a headless page bundle, and are sorted by weight. Each entry is a markdown file, containing both content, and, in the frontmatter, pixel-level positioning to adjust the boxouts to the image.
  • Log list, certificate count for homepage, monitor list, user agent list, and list of operators for the homepage are currently in data/ as JSON files. They are accessible via Hugo's .Site.Data object. In more detail:
    • List of log operators, monitors and user agents for the relevant individual pages are in data/logs.json, data/monitors.json and data/user_agents.json. These populate the relevant lists of cards on pages, in the order they are in the files. Logos should already be stored in static/img/collab-logos, and can be adjusted with the customWidth parameter if necessary.
    • List of "operators" for the homepage is in data/operators.json. These are displayed on the homepage in the order they're in in the JSON file. You can customise the width of a logo with the customWidth parameter to ensure balancing of sizes. If running the site locally, you will need to restart a hugo serve instance to see any changes made whilst it is running.
  • URLs for "Google Group" and "Github" are Site Parameters, and stored in (./config.yaml), and available in templates via .Site.Params. They are available in content pages using the {{< siteparams >}} shortcode.

Adding new timeline/logop/useragent/monitor entries


Automatic deployment

We currently deploy to Github Pages.

Currently, there's an action setup (in ./github/workflows/gh-pages.yml) that will build the site and deploy it to Github Pages on every commit to master.

It does this using actions for Github Pages by @peaceiris. It uses the per-repository GITHUB_TOKEN to authenticate this.

Every time you push to master, the action checks out the code, builds the site, pushes that build to the gh-pages branch and then, thanks to configuration, that's available at a Github Pages URL. That URL is secured through obscurity rather than anything else, which we've previously deemed acceptable for this project.

The CNAME for the site's URL is not stored in the repository; instead, it is set every time via the gh-pages action, and configured with the cname variable inside the workflow.

Note that the environment variable HUGO_ENV should be set to production to enable CSS minifcation/fingerprinting and to disable SCSS sourcemaps. This is currently the case on our Pages deployment, where it is made available as a Secret.

The site also automatically deploys whenever a Pull Request is closed.


Apache 2.0

This is not an official Google product.