docs: Build function docs from docstrings

Read the docstrings using ASTs instead of
importing the modules; this prevents the
need to install TuneD dependencies when
just building the docs (e.g., in Github Pages).

Author: zacikpa

.gitignore

@@ -4,3 +4,4 @@ tuned-*.tar.bz2
 *~
 *.html
 doc/manual/modules/performance/ref_available-tuned-plug-ins.adoc
+doc/manual/modules/performance/ref_built-in-functions-available-in-tuned-profiles.adoc

compile_plugin_docs.py

@@ -1,12 +1,14 @@
 .PHONY: clean
 
-index.html: master.adoc assemblies/*.adoc meta/*.adoc modules/performance/*.adoc ../../tuned/plugins/plugin_*.py
-	$(PYTHON) ../../compile_plugin_docs.py modules/performance/ref_available-tuned-plug-ins_intro.adoc modules/performance/ref_available-tuned-plug-ins.adoc
+index.html: master.adoc assemblies/*.adoc meta/*.adoc modules/performance/*.adoc ../../tuned/plugins/plugin_*.py ../../tuned/profiles/functions/function_*.py
+	$(PYTHON) ./compile_plugin_docs.py ../../tuned/plugins plugin_ Plugin modules/performance/ref_available-tuned-plug-ins_intro.adoc modules/performance/ref_available-tuned-plug-ins.adoc
+	$(PYTHON) ./compile_plugin_docs.py ../../tuned/profiles/functions function_ Function modules/performance/ref_built-in-functions-available-in-tuned-profiles_intro.adoc modules/performance/ref_built-in-functions-available-in-tuned-profiles.adoc
 	asciidoctor -o index.html master.adoc || asciidoc -d book -o index.html master.adoc
 
 install: index.html
 	install -Dpm 0644 index.html $(DESTDIR)$(DOCDIR)/manual/index.html
 
 clean:
 	rm -f modules/performance/ref_available-tuned-plug-ins.adoc
+	rm -f modules/performance/ref_built-in-functions-available-in-tuned-profiles.adoc
 	rm -f *.html

doc/manual/Makefile

@@ -0,0 +1,53 @@
+#!/usr/bin/env python3
+import argparse
+import ast
+import os
+import inspect
+
+
+class DocLoader:
+    def __init__(self, directory, prefix, base):
+        self._directory = directory
+        self._prefix = prefix
+        self._base = base
+
+    def _load_doc(self, module_path):
+        with open(module_path, "r") as file:
+            tree = ast.parse(file.read(), filename=module_path)
+        for node in ast.walk(tree):
+            if isinstance(node, ast.ClassDef) and any(
+                hasattr(base, "attr") and base.attr == self._base for base in node.bases
+            ):
+                return inspect.cleandoc(ast.get_docstring(node))
+        return ""
+
+    def load_all_docs(self):
+        docs = {}
+        for filename in os.listdir(self._directory):
+            if not filename.startswith(self._prefix):
+                continue
+            name = filename.split(".")[0].split("_", 1)[1]
+            path = os.path.join(self._directory, filename)
+            docs[name] = self._load_doc(path)
+        return docs
+
+
+if __name__ == "__main__":
+    parser = argparse.ArgumentParser()
+    parser.add_argument("directory")
+    parser.add_argument("prefix")
+    parser.add_argument("base")
+    parser.add_argument("intro")
+    parser.add_argument("out")
+    args = parser.parse_args()
+
+    with open(args.intro, "r") as intro_file:
+        intro = intro_file.read()
+
+    doc_loader = DocLoader(args.directory, args.prefix, args.base)
+    class_docs = doc_loader.load_all_docs()
+
+    with open(args.out, "w") as out_file:
+        out_file.write(intro)
+        for name, docs in class_docs.items():
+            out_file.writelines(["\n", "== **%s**\n" % name, "%s\n" % docs])

doc/manual/compile_plugin_docs.py

@@ -0,0 +1,6 @@
+:_module-type: REFERENCE
+[id="built-in-functions-available-in-tuned-profiles_{context}"]
+= Built-in functions available in TuneD profiles
+
+[role="_abstract"]
+The following built-in functions are available in all *TuneD* profiles: