Documenting Ceph

Code Documentation

C and C++ can be documented with Doxygen, using the subset of Doxygen markup supported by Asphyxiate.

The general format for function documentation is:

 * Short description
 * Detailed description when necessary
 * preconditons, postconditions, warnings, bugs or other notes
 * parameter reference
 * return value (if non-void)

This should be in the header where the function is declared, and functions should be grouped into logical categories. The librados C API provides a complete example. It is pulled into Sphinx by librados.rst, which is rendered at Librados (C).

Drawing diagrams


You can use Graphviz, as explained in the Graphviz extension documentation.

digraph "example" {
  foo -> bar;
  bar -> baz;
  bar -> thud;

Most of the time, you’ll want to put the actual DOT source in a separate file, like this:

.. graphviz::


You can use Ditaa:


If a use arises, we can integrate Blockdiag. It is a Graphviz-style declarative language for drawing things, and includes:


You can use Inkscape to generate scalable vector graphics. for restructedText documents.

If you generate diagrams with Inkscape, you should commit both the Scalable Vector Graphics (SVG) file and export a Portable Network Graphic (PNG) file. Reference the PNG file.

By committing the SVG file, others will be able to update the SVG diagrams using Inkscape.

HTML5 will support SVG inline.