jekyll-last-commit

Jekyll generator plugin and liquid tag to access the last commit information for a file.

Provides performant access to page.last_modified_at for Jekyll sites with very large page counts (100s+).

Use cases for a site page, document, static file, or data file:

• accessing the last commit date
• accessing the last committer name, email, and other metadata

Inspired by the work done at gjtorikian/jekyll-last-modified-at and aimed at improved performance. Seeks to be drop-in replacement. Uses libgit2/rugged rather than spawning a process.

Important:

• ignores commits where a file has been renamed without content changes
• has not been tested on Windows
• if your git repo uses SHA-256: the version of libgit2 that rugged uses must also support SHA-256
  • as of 2024 October, for the current libgit2 stable release v1.8.1, that means building libgit2 with -DEXPERIMENTAL_SHA256

The following is the last (most recent) commit from a repo:

main 5fde57927efdb2f440dd40c802687b60384e5d9d
Author:     Kip Landergren <klandergren@users.noreply.github.com>
AuthorDate: Fri Dec 16 18:30:53 2022 -0800
Commit:     Kip Landergren <klandergren@users.noreply.github.com>
CommitDate: Fri Dec 16 18:30:53 2022 -0800

add new pages to the site

Every page that was created or modified by this commit will get access to the commit’s information:

Additionally, last commit info is accessible for any data file via site.data.meta[data_file] with the same API:

Every page has their own last commit info computed during rebuild.

Add to your Gemfile:

group :jekyll_plugins do
  gem "jekyll-last-commit"
end

and run bundle install.

All of the following are optional:

jekyll-last-commit:
  date_format: '%F'                # default: `%B %d, %Y`
  # if a commit is not found `File.mtime` is used
  should_fall_back_to_mtime: false # default: `true`
  # enable processing of data and static files
  index_data_files: true           # default: false
  index_static_files: true         # default: false
  # information about data files is stored in a separate site.data hash
  data_files_key: 'meta'           # default: meta

The use case for should_fall_back_to_mtime is so that rendering of a file that is not yet tracked by git looks correct (e.g. a new, uncommitted blog post).

See Time#strftime documentation for available date format directives.

• page.last_commit
  • page.last_commit.author
    • page.last_commit.author.email
    • page.last_commit.author.name
    • page.last_commit.author.time
  • page.last_commit.committer
    • page.last_commit.committer.email
    • page.last_commit.committer.name
    • page.last_commit.committer.time
  • page.last_commit.message
  • page.last_commit.sha
  • page.last_commit.time
  • page.last_commit.time_epoch
• page.last_modified_at
• page.last_modified_at_formatted
• site.data.meta[data_file].last_commit
• site.data.meta[data_file].last_modified_at
• site.data.meta[data_file].last_modified_at_formatted
• last_modified_at

Gives access to the underlying rugged commit object information.

Important: ignores commits where a file has been renamed without content changes

Information about the author of the last commit for this file.

Information about the committer of the last commit for this file.

The Time object associated with the last commit for this file.

Example default output: 2022-12-11 19:54:26 -0800

Can be formatted using a liquid date filter:

{{ page.last_modified_at | date: '%B' }}

output:

December

The formatted string of the Time object associated with the last commit for this file. Format controlled via _config.yml.

Default format: %B %d, %Y

Example default output: December 11, 2022

Override in _config.yml via:

jekyll-last-commit:
  date_format: '%F'

If you need a per-page date format, use {{ page.last_modified_at | date: '%F }}' with whatever format string you want.

• data_file is the name of the file within _data/, e.g. foo.json
• .yml, .yaml, .json, .tsv, and .csv supported

See page.last_commit for further information.

• data_file is the name of the file within _data/, e.g. foo.json
• .yml, .yaml, .json, .tsv, and .csv supported

See page.last_modified_at for further information.

• data_file is the name of the file within _data/, e.g. foo.json
• .yml, .yaml, .json, .tsv, and .csv supported

See page.last_modified_at_formatted for further information.

A liquid tag that renders the formatted date using either the passed date format string, what was specified in _config.yml, or the default %B %d, %Y:

<p>{% last_modified_at %}</p>
<p>{% last_modified_at %F %D %}</p>

Added solely to be drop-in replacement with gjtorikian/jekyll-last-modified-at.

Comparison made to gjtorikian/jekyll-last-modified-at on a 2017 MacBook Pro running a 3.1 GHz Quad-Core Intel Core i7

generation command (note: no use of ---incremental):

$ JEKYLL_ENV=development bundle exec --gemfile=./static-site/Gemfile jekyll serve --port 4001 --source ./static-site --destination /tmp/_site_development

Walks the commit history until all documents and pages are matched to a commit. Falls back to File.mtime when no commit found. Runs fresh on each site generation.

See improving render performance via PATH_CACHE usage and bulk git log ... call #85 which includes two PRs more in line with that repository’s architecture and conventions.

Grabbing data via libgit2/rugged would be too big of a rewrite for what is a very popular plugin. If folks have performance issues getting page.last_modified_at they can safely compare their options using this!

1. It does not work with the old-style GitHub Pages integration, which doesn't allow third-party plugins.
2. It does not work with GitHub's https://github.com/actions/jekyll-build-pages action, which does not allow third-party gems either.
3. It works with the official Jekyll GitHub Action but needs you to configure the actions/checkout step with fetch-depth of 0 to ensure all Git history is fetched.

 - name: Checkout
    uses: actions/checkout@v4
    with:
      fetch-depth: 0