[RFC PATCH v4 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>
---
 buildtools/call-sphinx-build.py | 29 ++++++++++++-------
 doc/api/meson.build             |  1 +
 doc/guides/conf.py              | 32 +++++++++++++++++----
 doc/guides/meson.build          |  1 +
 doc/guides/tools/dts.rst        | 29 +++++++++++++++++++
 dts/doc/doc-index.rst           | 17 +++++++++++
 dts/doc/meson.build             | 50 +++++++++++++++++++++++++++++++++
 dts/meson.build                 | 16 +++++++++++
 meson.build                     |  1 +
 9 files changed, 161 insertions(+), 15 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/buildtools/call-sphinx-build.py b/buildtools/call-sphinx-build.py
index 39a60d09fa..c2f3acfb1d 100755
--- a/buildtools/call-sphinx-build.py
+++ b/buildtools/call-sphinx-build.py
@@ -3,37 +3,46 @@
 # Copyright(c) 2019 Intel Corporation
 #
 
+import argparse
 import sys
 import os
 from os.path import join
 from subprocess import run, PIPE, STDOUT
 from packaging.version import Version
 
-# assign parameters to variables
-(sphinx, version, src, dst, *extra_args) = sys.argv[1:]
+parser = argparse.ArgumentParser()
+parser.add_argument('sphinx')
+parser.add_argument('version')
+parser.add_argument('src')
+parser.add_argument('dst')
+parser.add_argument('--dts-root', default='.')
+args, extra_args = parser.parse_known_args()
 
 # set the version in environment for sphinx to pick up
-os.environ['DPDK_VERSION'] = version
+os.environ['DPDK_VERSION'] = args.version
+os.environ['DTS_ROOT'] = args.dts_root
 
 # for sphinx version >= 1.7 add parallelism using "-j auto"
-ver = run([sphinx, '--version'], stdout=PIPE,
+ver = run([args.sphinx, '--version'], stdout=PIPE,
           stderr=STDOUT).stdout.decode().split()[-1]
-sphinx_cmd = [sphinx] + extra_args
+sphinx_cmd = [args.sphinx] + extra_args
 if Version(ver) >= Version('1.7'):
     sphinx_cmd += ['-j', 'auto']
 
 # find all the files sphinx will process so we can write them as dependencies
 srcfiles = []
-for root, dirs, files in os.walk(src):
+for root, dirs, files in os.walk(args.src):
     srcfiles.extend([join(root, f) for f in files])
 
 # run sphinx, putting the html output in a "html" directory
-with open(join(dst, 'sphinx_html.out'), 'w') as out:
-    process = run(sphinx_cmd + ['-b', 'html', src, join(dst, 'html')],
-                  stdout=out)
+with open(join(args.dst, 'sphinx_html.out'), 'w') as out:
+    process = run(
+        sphinx_cmd + ['-b', 'html', args.src, join(args.dst, 'html')],
+        stdout=out
+    )
 
 # create a gcc format .d file giving all the dependencies of this doc build
-with open(join(dst, '.html.d'), 'w') as d:
+with open(join(args.dst, '.html.d'), 'w') as d:
     d.write('html: ' + ' '.join(srcfiles) + '\n')
 
 sys.exit(process.returncode)
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 0f7ff5282d..737e5a5688 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 +23,29 @@
           file=stderr)
     pass
 
+extensions = ['sphinx.ext.napoleon']
+
+# Python docstring options
+autodoc_default_options = {
+    'members': True,
+    'member-order': 'bysource',
+    'show-inheritance': True,
+}
+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 = False
+
+# Sidebar config
+html_theme_options = {
+    'collapse_navigation': False,
+    'navigation_depth': -1,
+}
+
 stop_on_error = ('-W' in argv)
 
 project = 'Data Plane Development Kit'
@@ -35,8 +57,8 @@
 html_show_copyright = False
 highlight_language = 'none'
 
-release = environ.setdefault('DPDK_VERSION', "None")
-version = release
+path.append(environ.get('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 32c18ee472..98923b1467 100644
--- a/doc/guides/tools/dts.rst
+++ b/doc/guides/tools/dts.rst
@@ -335,3 +335,32 @@ 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..f5dcd553f2
--- /dev/null
+++ b/dts/doc/doc-index.rst
@@ -0,0 +1,17 @@
+.. DPDK Test Suite documentation.
+
+Welcome to DPDK Test Suite's documentation!
+===========================================
+
+.. toctree::
+   :titlesonly:
+   :caption: Contents:
+
+   framework
+
+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..8e70eabc51
--- /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')
+sphinx_apidoc = find_program('sphinx-apidoc')
+
+if not sphinx.found() or not sphinx_apidoc.found()
+    subdir_done()
+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, '--append-syspath', '--force',
+            '--module-first', '--separate', '-V', meson.project_version(),
+            '-o', dts_api_build_dir, '--no-toc', '--implicit-namespaces',
+            dts_api_framework_dir],
+        build_by_default: false)
+doc_targets += dts_api_src
+doc_target_names += 'DTS_API_sphinx_sources'
+
+cp = find_program('cp')
+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: false)
+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,
+            '--dts-root', dts_dir, extra_sphinx_args],
+        build_by_default: false,
+        install: false,
+        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 39cb73846d..4d34dc531c 100644
--- a/meson.build
+++ b/meson.build
@@ -85,6 +85,7 @@ 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
-- 
2.34.1