doc: add ability to disambiguate clicmds

Multiple daemons have the same CLI commands defined, but the current
directive used to document CLI commands only takes the command
definition string. Since CLI command objects can be cross-referenced
using the :clicmd: directive, and are placed in the index, each object
needs to be unique.

To accomplish this, add a custom directive. This directive extends the
directive class used by sphinx's add_object_type to add a :daemon:
option. By specifying this option where needed, the object name becomes
"(<daemon>) <definition>", disambiguating it.

Signed-off-by: Quentin Young <qlyoung@qlyoung.net>

doc/user/conf.py

@@ -18,6 +18,8 @@ import re
 import pygments
 import sphinx
 from sphinx.highlighting import lexers
+from sphinx.domains.std import GenericObject
+from docutils.parsers.rst import directives
 
 # If extensions (or modules to document with autodoc) are in another directory,
 # add these directories to sys.path here. If the directory is relative to the
@@ -373,13 +375,49 @@ def vparse(s):
     return a[:3]
 
 
-# custom extensions here
+class ClicmdDirective(GenericObject):
+    """
+    Directive for documenting CLI commands.
+
+    The xref string, if no option is provided, will be the verbatim command
+    string. If the :daemon: option is provided, then it's
+    "(<daemon>) <command string>)".
+
+    Options:
+      :daemon: - specify the daemon this command belongs to. Useful for
+                 disambiguating multiple definitions of the same command.
+    """
+
+    has_content = True
+    required_arguments = 1
+    optional_arguments = 0
+    option_spec = {
+        **GenericObject.option_spec,
+        "daemon": directives.unchanged,
+    }
+
+    def handle_signature(self, sig, signode):
+        name = super().handle_signature(sig, signode)
+        daemon = self.options["daemon"] if "daemon" in self.options else ""
+        prefix = f"({daemon}) " if daemon else ""
+        return prefix + name
+
+    def run(self):
+        daemon = self.options["daemon"] if "daemon" in self.options else ""
+        if daemon:
+            self.indextemplate = f"pair: ({daemon}) %s; configuration command"
+        else:
+            self.indextemplate = f"pair: %s; configuration command"
+
+        nodes = super().run()
+
+        return nodes
+
+
 def setup(app):
-    # object type for FRR CLI commands, can be extended to document parent CLI
+    app.add_object_type("clicmd", "clicmd", objname="CLI command")
-    # node later on
+    # Override the directive that was just created for us
-    app.add_object_type(
+    app.add_directive_to_domain("std", "clicmd", ClicmdDirective, override=True)
-        "clicmd", "clicmd", indextemplate="pair: %s; configuration command"
-    )
 
     # I dont care how stupid this is
     if "add_js_file" in dir(app):