[RFC PATCH v1 3/4] dts: add doc generation

[Juraj Linkeš]

The tool used to generate developer docs is sphinx, which is already
used in DPDK. The configuration is kept the same to preserve the style.

Sphinx generates the documentation from Python docstrings. The docstring
format most suitable for DTS seems to be the Google format [0] which
requires the sphinx.ext.napoleon extension.

There are two requirements for building DTS docs:
* The same Python version as DTS or higher, because Sphinx import the
  code.
* Also the same Python packages as DTS, for the same reason.

[0] https://google.github.io/styleguide/pyguide.html#38-comments-and-docstrings

Signed-off-by: Juraj Linkeš <juraj.linkes at pantheon.tech>
---
 doc/api/meson.build      |  1 +
 doc/guides/conf.py       | 22 ++++++++++++++----
 doc/guides/meson.build   |  1 +
 doc/guides/tools/dts.rst | 29 +++++++++++++++++++++++
 doc/meson.build          |  5 ----
 dts/doc-index.rst        | 20 ++++++++++++++++
 dts/meson.build          | 50 ++++++++++++++++++++++++++++++++++++++++
 meson.build              |  6 +++++
 meson_options.txt        |  2 ++
 9 files changed, 126 insertions(+), 10 deletions(-)
 create mode 100644 dts/doc-index.rst
 create mode 100644 dts/meson.build

diff --git a/doc/api/meson.build b/doc/api/meson.build
index 2876a78a7e..ee70f09ef7 100644
--- a/doc/api/meson.build
+++ b/doc/api/meson.build
@@ -1,6 +1,7 @@
 # SPDX-License-Identifier: BSD-3-Clause
 # Copyright(c) 2018 Luca Boccassi <bluca at debian.org>
 
+api_build_dir = meson.current_build_dir()
 doxygen = find_program('doxygen', required: get_option('enable_docs'))
 
 if not doxygen.found()
diff --git a/doc/guides/conf.py b/doc/guides/conf.py
index a55ce38800..04c842b67a 100644
--- a/doc/guides/conf.py
+++ b/doc/guides/conf.py
@@ -7,10 +7,9 @@
 from sphinx import __version__ as sphinx_version
 from os import listdir
 from os import environ
-from os.path import basename
-from os.path import dirname
+from os.path import basename, dirname
 from os.path import join as path_join
-from sys import argv, stderr
+from sys import argv, stderr, path
 
 import configparser
 
@@ -24,6 +23,19 @@
           file=stderr)
     pass
 
+extensions = ['sphinx.ext.napoleon']
+
+# Python docstring options
+autodoc_member_order = 'bysource'
+autodoc_typehints = 'both'
+autodoc_typehints_format = 'short'
+napoleon_numpy_docstring = False
+napoleon_attr_annotations = True
+napoleon_use_ivar = True
+napoleon_use_rtype = False
+add_module_names = False
+toc_object_entries_show_parents = 'hide'
+
 stop_on_error = ('-W' in argv)
 
 project = 'Data Plane Development Kit'
@@ -35,8 +47,8 @@
 html_show_copyright = False
 highlight_language = 'none'
 
-release = environ.setdefault('DPDK_VERSION', "None")
-version = release
+path.append(environ.setdefault('DTS_ROOT', '.'))
+version = environ.setdefault('DPDK_VERSION', "None")
 
 master_doc = 'index'
 
diff --git a/doc/guides/meson.build b/doc/guides/meson.build
index 51f81da2e3..fed361060f 100644
--- a/doc/guides/meson.build
+++ b/doc/guides/meson.build
@@ -1,6 +1,7 @@
 # SPDX-License-Identifier: BSD-3-Clause
 # Copyright(c) 2018 Intel Corporation
 
+guides_source_dir = meson.current_source_dir()
 sphinx = find_program('sphinx-build', required: get_option('enable_docs'))
 
 if not sphinx.found()
diff --git a/doc/guides/tools/dts.rst b/doc/guides/tools/dts.rst
index ebd6dceb6a..332e2187a6 100644
--- a/doc/guides/tools/dts.rst
+++ b/doc/guides/tools/dts.rst
@@ -282,3 +282,32 @@ There are three tools used in DTS to help with code checking, style and formatti
 These three tools are all used in ``devtools/dts-check-format.sh``,
 the DTS code check and format script.
 Refer to the script for usage: ``devtools/dts-check-format.sh -h``.
+
+
+Building DTS API docs
+---------------------
+
+To build DTS API docs, install the dependencies with Poetry, then enter its shell:
+
+   .. code-block:: console
+
+   poetry install --with docs
+   poetry shell
+
+
+Build commands
+~~~~~~~~~~~~~~
+
+The documentation is built using the standard DPDK build system.
+
+After entering Poetry's shell, build the documentation with:
+
+   .. code-block:: console
+
+   ninja -C build doc
+
+The output is generated in ``build/doc/api/dts/html``.
+
+.. Note::
+
+   Make sure to fix any Sphinx warnings when adding or updating docstrings.
diff --git a/doc/meson.build b/doc/meson.build
index 6f74706aa2..5e08bb7b80 100644
--- a/doc/meson.build
+++ b/doc/meson.build
@@ -1,11 +1,6 @@
 # SPDX-License-Identifier: BSD-3-Clause
 # Copyright(c) 2018 Luca Boccassi <bluca at debian.org>
 
-doc_targets = []
-doc_target_names = []
-subdir('api')
-subdir('guides')
-
 if doc_targets.length() == 0
     message = 'No docs targets found'
 else
diff --git a/dts/doc-index.rst b/dts/doc-index.rst
new file mode 100644
index 0000000000..10151c6851
--- /dev/null
+++ b/dts/doc-index.rst
@@ -0,0 +1,20 @@
+.. DPDK Test Suite documentation master file, created by
+   sphinx-quickstart on Tue Mar 14 12:23:52 2023.
+   You can adapt this file completely to your liking, but it should at least
+   contain the root `toctree` directive.
+
+Welcome to DPDK Test Suite's documentation!
+===========================================
+
+.. toctree::
+   :maxdepth: 4
+   :caption: Contents:
+
+   modules
+
+Indices and tables
+==================
+
+* :ref:`genindex`
+* :ref:`modindex`
+* :ref:`search`
diff --git a/dts/meson.build b/dts/meson.build
new file mode 100644
index 0000000000..6ea7887f4b
--- /dev/null
+++ b/dts/meson.build
@@ -0,0 +1,50 @@
+# SPDX-License-Identifier: BSD-3-Clause
+# Copyright(c) 2023 PANTHEON.tech s.r.o.
+
+sphinx = find_program('sphinx-build', required: get_option('enable_dts_docs'))
+sphinx_apidoc = find_program('sphinx-apidoc', required: get_option('enable_dts_docs'))
+
+if sphinx.found() and sphinx_apidoc.found()
+endif
+
+dts_api_framework_dir = join_paths(meson.current_source_dir(), 'framework')
+dts_api_build_dir = join_paths(api_build_dir, 'dts')
+dts_api_src = custom_target('dts_api_src',
+        output: 'modules.rst',
+        command: ['SPHINX_APIDOC_OPTIONS=members,show-inheritance',
+            sphinx_apidoc, '--append-syspath', '--force',
+            '--module-first', '--separate',
+            '--doc-project', 'DTS', '-V', meson.project_version(),
+            '-o', dts_api_build_dir,
+            dts_api_framework_dir],
+        build_by_default: get_option('enable_docs'))
+doc_targets += dts_api_src
+doc_target_names += 'DTS_API_sources'
+
+cp = find_program('cp', required: get_option('enable_docs'))
+cp_index = custom_target('cp_index',
+        input: 'doc-index.rst',
+        output: 'index.rst',
+        depends: dts_api_src,
+        command: [cp, '@INPUT@', join_paths(dts_api_build_dir, 'index.rst')],
+        build_by_default: get_option('enable_docs'))
+doc_targets += cp_index
+doc_target_names += 'DTS_API_cp_index'
+
+extra_sphinx_args = ['-a', '-c', guides_source_dir]
+if get_option('werror')
+    extra_sphinx_args += '-W'
+endif
+
+htmldir = join_paths(get_option('datadir'), 'doc', 'dpdk')
+dts_api_html = custom_target('dts_api_html',
+        output: 'html',
+        depends: cp_index,
+        command: ['DTS_ROOT=@0@'.format(meson.current_source_dir()),
+            sphinx_wrapper, sphinx, meson.project_version(),
+            dts_api_build_dir, dts_api_build_dir, extra_sphinx_args],
+        build_by_default: get_option('enable_docs'),
+        install: get_option('enable_docs'),
+        install_dir: htmldir)
+doc_targets += dts_api_html
+doc_target_names += 'DTS_API_html'
diff --git a/meson.build b/meson.build
index f91d652bc5..48a4e12402 100644
--- a/meson.build
+++ b/meson.build
@@ -82,6 +82,12 @@ subdir('drivers')
 subdir('usertools')
 subdir('app')
 
+# define doc targets
+doc_targets = []
+doc_target_names = []
+subdir('doc/api')
+subdir('doc/guides')
+subdir('dts')
 # build docs
 subdir('doc')
 
diff --git a/meson_options.txt b/meson_options.txt
index 82c8297065..415b49fc78 100644
--- a/meson_options.txt
+++ b/meson_options.txt
@@ -16,6 +16,8 @@ option('drivers_install_subdir', type: 'string', value: 'dpdk/pmds-<VERSION>', d
        'Subdirectory of libdir where to install PMDs. Defaults to using a versioned subdirectory.')
 option('enable_docs', type: 'boolean', value: false, description:
        'build documentation')
+option('enable_dts_docs', type: 'boolean', value: false, description:
+       'Build DTS developer documentation.')
 option('enable_apps', type: 'string', value: '', description:
        'Comma-separated list of apps to build. If unspecified, build all apps.')
 option('enable_drivers', type: 'string', value: '', description:
-- 
2.30.2