diff --git a/swh/docs/sphinx/conf.py b/swh/docs/sphinx/conf.py
index beaa157..607e398 100755
--- a/swh/docs/sphinx/conf.py
+++ b/swh/docs/sphinx/conf.py
@@ -1,159 +1,160 @@
 #!/usr/bin/env python3
 # -*- coding: utf-8 -*-
 #
 
 import django
 import os
 
 # General information about the project.
 project = 'Software Heritage - Development Documentation'
 copyright = '2015-2019  The Software Heritage developers'
 author = 'The Software Heritage developers'
 
 # -- General configuration ------------------------------------------------
 
 # Add any Sphinx extension module names here, as strings. They can be
 # extensions coming with Sphinx (named 'sphinx.ext.*') or your custom
 # ones.
 extensions = ['sphinx.ext.autodoc',
               'sphinx.ext.napoleon',
               'sphinxcontrib.httpdomain',
               'sphinx.ext.extlinks',
               'sphinxcontrib.images',
               'sphinxcontrib.programoutput',
               'sphinx.ext.viewcode',
               'sphinx_tabs.tabs',
               'sphinx_rtd_theme',
+              'sphinx.ext.graphviz',
               ]
 
 # Add any paths that contain templates here, relative to this directory.
 templates_path = ['_templates']
 
 # The suffix(es) of source filenames.
 # You can specify multiple suffix as a list of string:
 #
 source_suffix = ['.rst', '.md']
 # source_suffix = '.rst'
 
 source_parsers = {
    '.md': 'recommonmark.parser.CommonMarkParser',
 }
 
 # The master toctree document.
 master_doc = 'index'
 
 # A string of reStructuredText that will be included at the beginning of every
 # source file that is read.
 # A bit hackish but should work both for each swh package and the whole swh-doc
 rst_prolog = '''
 .. include:: /../../swh-docs/docs/swh_substitutions
 '''
 
 # The version info for the project you're documenting, acts as replacement for
 # |version| and |release|, also used in various other places throughout the
 # built documents.
 #
 # The short X.Y version.
 version = ''
 # The full version, including alpha/beta/rc tags.
 release = ''
 
 # The language for content autogenerated by Sphinx. Refer to documentation
 # for a list of supported languages.
 #
 # This is also used if you do content translation via gettext catalogs.
 # Usually you set "language" from the command line for these cases.
 language = 'en'
 
 # List of patterns, relative to source directory, that match files and
 # directories to ignore when looking for source files.
 # This patterns also effect to html_static_path and html_extra_path
 exclude_patterns = ['_build']
 
 # The name of the Pygments (syntax highlighting) style to use.
 pygments_style = 'sphinx'
 
 # If true, `todo` and `todoList` produce output, else they produce nothing.
 todo_include_todos = True
 
 
 # -- Options for HTML output ----------------------------------------------
 
 # The theme to use for HTML and HTML Help pages.  See the documentation for
 # a list of builtin themes.
 #
 html_theme = 'sphinx_rtd_theme'
 
 html_favicon = '_static/favicon.ico'
 
 # Theme options are theme-specific and customize the look and feel of a theme
 # further.  For a list of options available for each theme, see the
 # documentation.
 #
 html_theme_options = {
     'collapse_navigation': True,
     'sticky_navigation': True,
 }
 
 html_logo = 'software-heritage-logo-title-motto-vertical-white.png'
 
 # Add any paths that contain custom static files (such as style sheets) here,
 # relative to this directory. They are copied after the builtin static files,
 # so a file named "default.css" will overwrite the builtin "default.css".
 html_static_path = ['_static']
 
 # make logo actually appear, avoiding gotcha due to alabaster default conf.
 # https://github.com/bitprophet/alabaster/issues/97#issuecomment-303722935
 html_sidebars = {
     '**': [
         'about.html',
         'globaltoc.html',
         'relations.html',
         'sourcelink.html',
         'searchbox.html',
     ]
 }
 
 # If not None, a 'Last updated on:' timestamp is inserted at every page
 # bottom, using the given strftime format.
 # The empty string is equivalent to '%b %d, %Y'.
 html_last_updated_fmt = "%Y-%m-%d %H:%M:%S %Z"
 
 # refer to the Python standard library.
 intersphinx_mapping = {'python': ('https://docs.python.org/3', None)}
 
 
 # -- autodoc configuration ----------------------------------------------
 autodoc_default_flags = ['members', 'undoc-members', 'private-members',
                          'special-members']
 autodoc_member_order = 'bysource'
 autodoc_mock_imports = ['rados']
 
 modindex_common_prefix = ['swh.']
 
 # for the extlinks extension, sub-projects should fill that dict
 extlinks = {}
 
 
 # XXX Kill this ASA this PR is accepted and released
 # https://github.com/sphinx-contrib/httpdomain/pull/19
 def register_routingtable_as_label(app, document):
     from sphinx.locale import _  # noqa
     labels = app.env.domaindata['std']['labels']
     labels['routingtable'] = 'http-routingtable', '', _('HTTP Routing Table')
     anonlabels = app.env.domaindata['std']['anonlabels']
     anonlabels['routingtable'] = 'http-routingtable', ''
 
 
 # hack to set the adequate django settings when building global swh doc
 # to avoid autodoc build errors
 def setup(app):
     os.environ.setdefault('DJANGO_SETTINGS_MODULE',
                           'swh.docs.django_settings')
     django.setup()
     import pkg_resources  # noqa
     from distutils.version import StrictVersion  # noqa
 
     httpdomain = pkg_resources.get_distribution('sphinxcontrib-httpdomain')
     if StrictVersion(httpdomain.version) <= StrictVersion('1.7.0'):
         app.connect('doctree-read', register_routingtable_as_label)