[RFC PATCH v2 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 +++++++++++++++++++++++
 dts/doc/doc-index.rst    | 20 ++++++++++++++++
 dts/doc/meson.build      | 50 ++++++++++++++++++++++++++++++++++++++++
 dts/meson.build          | 16 +++++++++++++
 meson.build              |  1 +
 meson_options.txt        |  2 ++
 9 files changed, 137 insertions(+), 5 deletions(-)
 create mode 100644 dts/doc/doc-index.rst
 create mode 100644 dts/doc/meson.build
 create mode 100644 dts/meson.build

diff --git a/doc/api/meson.build b/doc/api/meson.build
index 2876a78a7e..1f0c725a94 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>
 
+doc_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..8933d75f6b 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
 
+doc_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..a547da2017 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 dts/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/dts/doc/doc-index.rst b/dts/doc/doc-index.rst
new file mode 100644
index 0000000000..10151c6851
--- /dev/null
+++ b/dts/doc/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/doc/meson.build b/dts/doc/meson.build
new file mode 100644
index 0000000000..db2bb0bed9
--- /dev/null
+++ b/dts/doc/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(dts_dir, 'framework')
+dts_api_build_dir = join_paths(doc_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_dts_docs'))
+doc_targets += dts_api_src
+doc_target_names += 'DTS_API_sphinx_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_dts_docs'))
+doc_targets += cp_index
+doc_target_names += 'DTS_API_sphinx_index'
+
+extra_sphinx_args = ['-a', '-c', doc_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(dts_dir),
+            sphinx_wrapper, sphinx, meson.project_version(),
+            dts_api_build_dir, dts_api_build_dir, extra_sphinx_args],
+        build_by_default: get_option('enable_dts_docs'),
+        install: get_option('enable_dts_docs'),
+        install_dir: htmldir)
+doc_targets += dts_api_html
+doc_target_names += 'DTS_API_HTML'
diff --git a/dts/meson.build b/dts/meson.build
new file mode 100644
index 0000000000..17bda07636
--- /dev/null
+++ b/dts/meson.build
@@ -0,0 +1,16 @@
+# SPDX-License-Identifier: BSD-3-Clause
+# Copyright(c) 2023 PANTHEON.tech s.r.o.
+
+doc_targets = []
+doc_target_names = []
+dts_dir = meson.current_source_dir()
+
+subdir('doc')
+
+if doc_targets.length() == 0
+    message = 'No docs targets found'
+else
+    message = 'Built docs:'
+endif
+run_target('dts/doc', command: [echo, message, doc_target_names],
+    depends: doc_targets)
diff --git a/meson.build b/meson.build
index f91d652bc5..7820f334bb 100644
--- a/meson.build
+++ b/meson.build
@@ -84,6 +84,7 @@ subdir('app')
 
 # build docs
 subdir('doc')
+subdir('dts')
 
 # build any examples explicitly requested - useful for developers - and
 # install any example code into the appropriate install path
diff --git a/meson_options.txt b/meson_options.txt
index 82c8297065..267f1b3ef7 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 API 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