December 3, 2020

Quick Start Guide

  1. Features
  2. Prerequisites
  3. Usage
    1. Creating a New Site
    2. Running the Server
      1. Changing the port
    3. Building the static site
    4. Site Configuration
    5. Switching between Markdown and AsciiDoc
    6. Selecting a Theme
    7. Customizing Layouts
    8. Code Syntax Highlighting
  4. Deploying Your Site
  5. Third Party Libraries
  6. Some Sites Made With Cryogen

This intro only documents a subset of Cryogen's features. For additional documentation please see the cryogen site.


  • Blog posts and pages with Markdown (default) or AsciiDoc
  • Tags
  • Table of contents generation
  • Plain HTML page templates
  • Code syntax highlighting
  • Disqus support
  • Sitemap generation
  • RSS feed generation
  • Sass/SCSS compilation
  • Klipse Integration


You will need Leiningen 2.5.0 or above installed.


Creating a New Site

A new site can be created using the Cryogen template as follows:

lein new cryogen my-blog

or, alternatively, using clj-new as a tool:

clojure -Ttools install com.github.seancorfield/clj-new '{:git/tag "v1.2.362"}' :as clj-new # update to latest!
clojure -Tclj-new create :template cryogen :name myname/myblog :force true
cd myname/myblog/

Running the Server

The web server can be started from the my-blog directory using either Leiningen:

lein serve # or lein serve:fast

or tools-deps:

clojure -X:serve # or clojure -X:serve:fast

The server will watch for changes in the content and themes folders and recompile the content automatically. The *:fast variants perform fast but partial compilation of only the changed page/post.

Changing the port

You can either change the hard-coded port in deps.edn / server.clj or override it by setting the PORT env var.

Building the static site

You can also generate the content without bringing up a server either via:

lein run

or via:

clojure -M:build

Site Configuration

The site configuration file is found at content/config.edn, this file looks as follows:

{:site-title                   "My Awesome Blog"
 :author                       "Bob Bobbert"
 :description                  "This blog is awesome"
 :site-url                     ""
 :post-root                    "posts"
 :page-root                    "pages"
 :post-root-uri                "posts-output"
 :page-root-uri                "pages-output"
 :tag-root-uri                 "tags-output"
 :author-root-uri              "authors-output"
 :public-dest                  "public"
 :blog-prefix                  "/blog"
 :rss-name                     "feed.xml"
 :rss-filters                  ["cryogen"]
 :recent-posts                 3
 :post-date-format             "yyyy-MM-dd"
 :archive-group-format         "yyyy MMMM"
 :sass-src                     []
 :sass-path                    "sass"
 :theme                        "blue"
 :resources                    ["img"]
 :keep-files                   [".git"]
 :disqus?                      false
 :disqus-shortname             ""
 :ignored-files                [#"\.#.*" #".*\.swp$"]
 :previews?                    false
 :posts-per-page               5
 :blocks-per-preview           2
 :clean-urls                   :trailing-slash
 :collapse-subdirs?            false
 :hide-future-posts?           true
 :klipse                       {}
 :description-include-elements #{:p :h1 :h2 :h3 :h4 :h5 :h6}
 :debug?                       false}

For information about each key please see the "Configuration" portion of the Cryogen documentation site.

Switching between Markdown and AsciiDoc

Cryogen comes with Markdown support as default. If you want to use AsciiDoc instead, open the project.clj in your created blog (e.g. my-blog), and change the line in :dependencies that says cryogen-markdown to cryogen-asciidoc (and ensure the right version). Instead of looking for files ending in .md in the content/md directory, the compiler will now look for files ending in .asc in the content/asc directory.

Selecting a Theme

The Cryogen template comes with three themes in the themes folder. To change your blog's theme, change the value of the :theme key in config.edn. Note that the Nucleus theme is obtained from that requires you to keep the footer, unless you make a donation on their website.

Customizing Layouts

Cryogen uses Selmer templating engine for layouts. Please refer to its documentation to see the supported tags and filters for the layouts.

The layouts are contained in the themes/{theme}/html folder of the project. By default, the base.html layout is used to provide the general layout for the site. This is where you would add static resources such as CSS and JavaScript assets as well as define headers and footers for your site.

Each page layout should have a name that matches the :layout key in the page metadata and end with .html. Page layouts extend the base layout and should only contain the content relevant to the page inside the content block. For example, the tag layout is located in tag.html and looks as follows:

{% extends "/html/base.html" %}
{% block content %}
<div id="posts-by-tag">
    <h2>Posts tagged {{name}}</h2>
    {% for post in posts %}
            <a href="{{post.uri}}">{{post.title}}</a>
    {% endfor %}
{% endblock %}

Code Syntax Highlighting

Cryogen uses Highlight.js for code syntax highlighting. You can add more languages by replacing themes/{theme}/js/highlight.pack.js with a customized package from here.

The initHighlightingOnLoad function is called in themes/{theme}/html/base.html.


Deploying Your Site

The generated static content will be found under the public folder. Simply copy the content to a static folder for a server such as Nginx or Apache and your site is now ready for service.

A sample Nginx configuration that's placed in /etc/nginx/sites-available/default can be seen below:

server {
  listen 80 default_server;
  listen [::]:80 default_server ipv6only=on;
  server_name localhost <> <>;

  access_log  /var/log/blog_access.log;
  error_log   /var/log/blog_error.log;

  location / {
    alias       /var/blog/;
    error_page  404 = /404.html;

Simply set to the domain of your site in the above configuration and ensure the static content is available at /var/blog/. Finally, place your custom error page in the /var/blog/404.html file.

More information on deployment can be found here.

Third Party Libraries

A Clojure library to provide Markdown rendering to the cryogen-core compiler by using an external command/program, such as pandoc.

Some Sites Made With Cryogen

Tags: cryogen