Gojekyll

Gojekyll is an incomplete implementation of the Jekyll static site generator in the Go programming language.

This was my “weekend project” for learning Go, that took on a life of its own (and more than a weekend).

• Gojekyll
  • Installation
  • Usage
  • Status
    • Major omissions
    • Other Caveats
    • Intentional Differences
    • Timings
    • Features
  • Contributing
    • Testing
    • Profiling
  • Credits
  • Related
  • License

Installation

1. Install go. On macOS running Homebrew, brew install go is easier than the linked instructions.
2. go get -u osteele/gojekyll/cmd/gojekyll
3. To use the {% highlight %} tag, you need to install Pygments: pip install Pygments.

Usage

gojekyll -s path/to/site build                # builds into ./_site
gojekyll -s path/to/site serve                # serves from memory, w/ live reload
gojekyll help
gojekyll help build

Status

Major omissions

• Major features: themes, page tags, excerpts, plugins (except for avatar), pagination, math, warning mode
• Site variables: pages, static_files, html_pages, html_files, documents, and tags
• Jekyll filters: group_by_exp, pop, shift, cgi_escape, uri_escape, scssify, and smartify.
• Jekyll's include_relative and gist
• The Go Liquid is also missing some tags and a few filters. See its README for status.
• Data files must be YAML. CSV and JSON are not (yet) supported.
• {% highlight %} uses Pygments. There's no way to tell it to use Rouge. Also, I don't know what will happen if Pygments isn't installed.
• <div markdown=1> doesn't work. I think this is a limitation of the Blackfriday Markdown processor.

Other Caveats

• The Liquid engine is probably much stricter than the original.
• This implementation is much less robust. It probably panics or otherwise fails on a lot of legitimate constructs.
• Liquid errors aren't reported very nicely.

Intentional Differences

• serve generates pages on the fly; it doesn't write to the file system.
• Files are cached to /tmp/gojekyll-${USER}, not ./.sass-cache
• Server live reload is always on.
• The server reloads the _config.yml (and the rest of the site) when it changes.
• build with no -d option resolves the destination relative to the source directory, not the current directory.

Timings

[go]jekyll -s jekyll/docs build

Executable	Options	Time
jekyll		18.53s
gojekyll	single-threaded; cold cache	6.85s
gojekyll	single-threaded; warm cache	0.61s
gojekyll	multi-threaded; cache doesn't matter	0.34s

There's currently no way to disable concurrency or the cache. They were switched off by editing the code for these timings.

The cache is for calls to Pygments via the highlight tag.

Features

• Content
  • Front Matter
  • Posts
    • Categories
    • Tags
    • Drafts
    • Future
    • Related
  • Static Files
  • Variables
  • Collections
  • Data Files
    • CSV
    • JSON
    • YAML
  • Assets
    • Coffeescript
    • Sass/SCSS
• Customization
  • Templates
    • Jekyll filters
      • group_by_exp pop shift cgi_escape uri_escape scssify smartify
      • everything else
    • Jekyll tags
      • include
      • include_relative
      • link
      • post_url
      • gist
      • highlight
  • Includes
    • include parameters
    • include variables (e.g. {% include {{ expr }} %})
  • Permalinks
  • Pagination
  • Plugins
    • jekyll-avatar
    • jekyll-coffeescript
    • jekyll-live-reload (always on)
    • jekyll-paginate
  • Themes
  • Layouts
• Server
  • Directory watch
• Commands
  • build
    • --source, --destination, --drafts, --future, --unpublished
    • --config, --baseurl, --lsi, --watch, etc.
    • won't implement: --force-polling, --limit-posts, --incremental, JEKYLL_ENV=production
  • clean
  • doctor
  • help
  • import
  • new
  • new-theme
  • serve
    • --open-uri
    • --detach, --host, --port, --baseurl
    • won't implement: --incremental, --ssl-*
• Windows

Contributing

Install package dependencies and development tools:

make setup

Testing

make test
make lint
gojekyll  -s path/to/site render index.md      # render a file to stdout
gojekyll  -s path/to/site render /             # render a URL to stdout
gojekyll  -s path/to/site variables /          # print a file or URL's variables
./scripts/coverage && go tool cover -html=coverage.out

./scripts/gojekyll is an alternative to the gojekyll executable, that uses go run each time it's invoked.

Profiling

gojekyll -s path/to/site profile
go tool pprof gojekyll gojekyll.prof

Credits

Gojekyll uses these libraries:

Package	Author(s)	Description	License
github.com/jaschaephraim/lrserver	Jascha Ephraim	Live Reload server	MIT
github.com/osteele/liquid	yours truly	Liquid processor	MIT
github.com/pkg/browser	pkg	The serve -o option to open the site in the browser	BSD 2-clause "Simplified" License
github.com/russross/blackfriday	Russ Ross	Markdown processor	Simplified BSD License
github.com/sass/libsass	Listed here	C port of the Ruby SASS compiler	MIT
github.com/wellington/go-libsass	Drew Wells	Go bindings for libsass	???
gopkg.in/alecthomas/kingpin.v2	Alec Thomas	command line and flag parser	MIT
gopkg.in/yaml.v2	Canonical	YAML support	Apache License 2.0

In addition to being totally and obviously inspired by the Jekyll, Jekyll's solid documentation was indispensible. Many of the filter test cases are taken directly from the Jekyll documentation, and the Jekyll docs were always open in at least one tab.

The help text was taken from the output of jekyll help.

The gopher image in the test directory is from Wikimedia Commons. It is used under the Creative Commons Attribution-Share Alike 3.0 Unported license.

Related

Hugo isn't Jekyll-compatible (-), but actually works (+++).

Liquid is a Go implementation of Liquid templates. I ended up having to write that in order to finish this, but in principle it could be used elsewhere.

Jekyll, of course.

License

MIT