Implement ability to limit module documentation building (#24576)

* Implement ability to limit module documentation building:

- Added new option to plugin_formatter.py to support passing-in a list of
  modules for which the documentation should be built.
- Updated docuemtnation Makefile to allow specifying list of modules via
  environment variables (defaulting to all modules).
- Update instructions for building documentation and module development to
  include commands and description of limiting module documentation builds.

* Updated implementation for limiting module documentation building:

- Pass list of modules (or None) to list_modules function instead of string.
- Move conversion of module list to argument parsing code.
- No special keywords. Default ("") means build all modules. For no modules just
  specify non-existing module name.
- Updated documentation to reflect the changes.

* Updated implementation for limiting module documentation building:

- Use better default value, and don't treat "" as special case.
- Conditionally invoke different variants of command in Makefile instead of
  using special value "".

* Minor edits

Wording tweak

docs/bin/plugin_formatter.py

@@ -117,7 +117,7 @@ def write_data(text, options, outputname, module):
         print(text)
 
 
-def list_modules(module_dir, depth=0):
+def list_modules(module_dir, depth=0, limit_to_modules=None):
     ''' returns a hash of categories, each category being a hash of module names to file paths '''
 
     categories = dict()
@@ -159,6 +159,9 @@ def list_modules(module_dir, depth=0):
             aliases[source].add(module)
             continue
 
+        # If requested, limit module documentation building only to passed-in
+        # modules.
+        if limit_to_modules is None or module.lower() in limit_to_modules:
             category[module] = module_path
             module_info[module] = module_path
 
@@ -185,6 +188,8 @@ def generate_parser():
     p.add_option("-v", "--verbose", action='store_true', default=False, help="Verbose")
     p.add_option("-o", "--output-dir", action="store", dest="output_dir", default=None, help="Output directory for module files")
     p.add_option("-I", "--includes-file", action="store", dest="includes_file", default=None, help="Create a file containing list of processed modules")
+    p.add_option("-l", "--limit-to-modules", action="store", dest="limit_to_modules", default=None,
+                 help="Limit building module documentation to comma-separated list of modules. Specify non-existing module name for no modules.")
     p.add_option('-V', action='version', help='Show version number and exit')
     return p
 
@@ -435,7 +440,11 @@ def main():
 
     env, template, outputname = jinja2_environment(options.template_dir, options.type)
 
-    mod_info, categories, aliases = list_modules(options.module_dir)
+    # Convert passed-in limit_to_modules to None or list of modules.
+    if options.limit_to_modules is not None:
+        options.limit_to_modules = [s.lower() for s in options.limit_to_modules.split(",")]
+
+    mod_info, categories, aliases = list_modules(options.module_dir, limit_to_modules=options.limit_to_modules)
     categories['all'] = mod_info
     categories['_aliases'] = aliases
     category_names = [c for c in categories.keys() if not c.startswith('_')]

docs/docsite/Makefile

@@ -50,7 +50,12 @@ keywords: $(FORMATTER) ../templates/playbooks_keywords.rst.j2
 	PYTHONPATH=../../lib $(DUMPER) --template-dir=../templates --output-dir=rst/ -d ./keyword_desc.yml
 
 modules: $(FORMATTER) ../templates/plugin.rst.j2
+# Limit building of module documentation if requested.
+ifdef MODULES
+	PYTHONPATH=../../lib $(FORMATTER) -t rst --template-dir=../templates --module-dir=../../lib/ansible/modules -o rst/ -l $(MODULES)	
+else
 	PYTHONPATH=../../lib $(FORMATTER) -t rst --template-dir=../templates --module-dir=../../lib/ansible/modules -o rst/
+endif
 
 testing:
 	$(TESTING_FORMATTER)

docs/docsite/README.md

@@ -14,6 +14,12 @@ such as link references, you may install sphinx and build the documentation by r
 To include module documentation you'll need to run `make webdocs` at the top level of the repository.  The generated
 html files are in docsite/htmlout/.
 
+To limit module documentation building to a specific module, run `MODULES=NAME
+make webdocs` instead. This should make testing module documentation syntax much
+faster. Instead of a single module, you can also specify a comma-separated list
+of modules. In order to skip building documentation for all modules, specify
+non-existing module name, for example `MODULES=none make webdocs`.
+
 If you do not want to learn the reStructuredText format, you can also [file issues] about
 documentation problems on the Ansible GitHub project.
 

docs/docsite/rst/dev_guide/developing_modules_documenting.rst

@@ -383,6 +383,13 @@ Put your completed module file into the ``lib/ansible/modules/$CATEGORY/`` direc
 run the command: ``make webdocs``. The new 'modules.html' file will be
 built in the ``docs/docsite/_build/html/$MODULENAME_module.html`` directory.
 
+In order to speed up the build process, you can limit the documentation build to 
+only include modules you specify, or no modules at all. To do this, run the command:
+``MODULES=$MODULENAME make webdocs``. The ``MODULES`` environment variable
+accepts a comma-separated list of module names. To skip building
+documentation for all modules, specify a non-existent module name, for example:
+``MODULES=none make webdocs``.
+
 To test your documentation against your ``argument_spec`` you can use ``validate-modules``. Note that this option isn't currently enabled in Shippable due to the time it takes to run.
 
 .. code-block:: bash