The project directory

A typical Urubu project directory looks as follows:


Files and directories with pathnames starting with an underscore _ are special. They are used during processing, but excluded from the built website. Their function will be discussed below.

The css and js directories are just an example of how CSS style sheets and javascript files could be organized. You can use any organization that you prefer.

Content files are in Markdown format and should have the .md extension. You have complete freedom in organizing them in directories. However, every directory should have an file, including the top-level directory.

Processing rules

Urubu generates a website by processing the files and directory in the project directory, and putting the result in a _build subdirectory. The processing depends on the pathname as follows:

  • a Makefile is ignored and not copied to the build.

  • files and directories starting with a dot . or underscore _ are ignored and not copied to the build.

  • Markdown files with extension .md are converted to a html file that is put into the build in the same relative location.

  • all other files and directories are copied unmodified to the build in the same relative location.

As a result of the project organization and the build process, the structure of the build matches the structure of the project directory. The relative location of all files is thus preserved.

Special files and directories


This file contains site configuration info in YAML format. Currently, these are the predefined attributes:

Attribute Description
reflinks Holds a mapping from reference ids to link objects.
baseurl Prefix for generated local URLs
file_ext Change default file extension ('.html') for processed .md files
link_ext Change default file extension ('.html') for links to site's pages
ignore_patterns List of additional file names or globs to be ignored during processing
keep_files List of explicit file names be kept, overriding any ignores
strict_undefined Set the default behavior regarding undefined template variables

Link objects, for the reflinks attribute, are a mapping with an url key that maps to the link URL and a title key that maps to the link title.

The baseurl option mirrors the same feature in Jekyll. It allows you to specify a prefix for all local URLs generated within your site. This is necessary when your site will be served from a URL that has more than just the hostname. For example, on GitHub Pages sites are served from, so Urubu needs to include that /project_name/ in generated URLs pointing to local content.

baseurl should be specified with no beginning or trailing slashes, e.g.:

baseurl: prefix

The file extension attributes, file_ext and link_ext, are both usually set to the same value (i.e. '.php'), unless the target site has .htaccess rewrite rules that affect the file extensions.

Examples of this are sites that internally redirect pages like to For this case, one would need to set file_ext to '.htm', so Urubu generated files have the .htm extension, whereas link_ext would be set to '', so that the a href links are directed to the files without extension.

Otherwise, file_ext and link_ext should be set to the same extension, specially during testing, so that the simple web server invoked by urubu serve works fine, as well as any web server that does not rewrite the file extensions of the requests.

The ignore_patterns attribute specifies glob-style patterns to be ignored during processing, in addition to the default ones according to the Processing Rules.

In some cases you may explicitly want to keep certain files that would normally be ignored. For example, you may have hidden files like .nojekyll to prevent Jekyll processing, or .htaccess and .htpasswd for access control. You can keep such files in the build using the keep_files attribute.

The strict_undefined attribute controls whether the build should silently ignore undefined template variables or raise an error when they are encountered. If false or undefined, undefined template variables are treated as empty strings (''). If true, the build will stop and raise an error.

You can define additional attributes that will be made available as site variables to the template engine. The following is an example of a _site.yml file:

brand: Urubu

        title: CC-BY-SA License
        title: GNU Affero General Public License
        title: Markdown

file_ext: '.htm'  # Change default file extension ('.html')
link_ext: '.htm'  # Change default link extension ('.html')


This directory contains the available layouts. They are used by the Jinja2 template engine to render html pages. The layout files should have the .html extension.


This directory contains Python hooks for the template engine.

Project-wide reference ids

Urubu has the concept of project-wide reference ids. You can use them to refer to link objects in your content and configuration. Their definition comes from two sources:

  • global reference ids are mapped to link objects in the _site.yml configuration file, as discussed earlier.
  • all content pages and folders objects have reference ids.

Project-wide references ids live in a single namespace. For pages and folders, the id is a root-relative pathname starting with a slash / and without file extension. By convention, global reference ids should not start with a /.

In your content and configuration info, you can also use relative reference ids. Urubu will resolve them depending on the file location in the project. In case of a name clash with a global reference id, you will have to disambiguate by adding pathname components.

In accordance with Markdown conventions, reference ids are case-insensitive.

Content files

Content files are Markdown files with extension .md. They should start with YAML front matter that defines a number of attributes, as in the following example:

title: Read me first
layout: page
date: 2014-01-15
<Markdown content>

The following attributes are predefined:

Attribute Description
title Specifies the page title. Mandatory.
layout Specifies the layout, without the .html extension, or null. Mandatory.
date Specifies the date in YYYY-MM-DD format. Optional.
tags A tag or list of tags for the content.
saveas Allows overriding of the output filename.

The layout attribute is mandatory, but can be given a null value. This is useful when the page content is used by other pages, but no html output is required for the page itself.

In addition, you can add arbitrary user-defined attributes. All attributes are made available as page object attributes to the template engine.

Markdown in attributes

Optionally, you can use markdown format in front matter attributes. Markdown processing is enabled by adding a .md suffix to the attribute. The resulting html code will be stored in a synthesized attribute without the .md suffix.

For example:

layout: page |
    A summary of the page items as a list:

    * item 1
    * item 2
    * item 3

After processing, the page object will have a summary attribute with the html code.

Index files

Index files with basename are a special kind of content files. They are used to specify the attributes and the content of a directory. There are two options to specify the content, explicitly with the content attribute or implicitly using the order attribute.

Attribute Description
content Defines the content explicitly as a list of reference ids or local link objects.
order Defines the attribute by which the content in the directory should be ordered.
reverse Optional boolean attribute defines reverse order or not. Default is false.

content and order are mutually exclusive; you should use one of the two options.

A local link object is a mapping with either a url key to an url, or a ref key to a reference id as mandatory items. In addtion, you can specify a title with a title key.

The ordering attribute can be predefined or user-defined, but it should be specified in each content file in the directory. As an example, you can specify that the content of a directory should be ordered as blog by the following front matter in the index file:

title: Blog
layout: blog_index
order: date
reverse: true

Tag directory

The optional top-level directory called tag has a predefined meaning. Urubu uses the corresponding folder in the build to hold the tag-related content view that it generates automatically. You can use the index file to set attributes such as the layout. However, the content will be generated by Urubu automatically and needs not be set.