speed up doc build (#694)

Summary: Pull Request resolved: #694

Reviewed By: schwarzmx

Differential Revision: D53143804

fbshipit-source-id: 374f0d9104641f1ad3093356984082ee203512f6

docs/source/conf.py

@@ -50,13 +50,18 @@
 # Add any Sphinx extension module names here, as strings. They can be
 # extensions coming with Sphinx (named 'sphinx.ext.*') or your custom
 # ones.
-extensions = [
-    "sphinx.ext.napoleon",
-    "sphinx.ext.autodoc",
-    "sphinx.ext.autosummary",
-    "sphinx.ext.viewcode",
-    "fbcode",
-]
+
+barebones = os.getenv("BAREBONES", None)
+if barebones:
+    extensions = ["fbcode"]
+else:
+    extensions = [
+        "sphinx.ext.napoleon",
+        "sphinx.ext.autodoc",
+        "sphinx.ext.autosummary",
+        "sphinx.ext.viewcode",
+        "fbcode",
+    ]
 
 FBCODE = "fbcode" in os.getcwd()