CI: Improve time to create PDF file

Note: Now we leverage the doctree to create the PDF file after
the HTML file. The doctree is then deleted to avoid the issue
we had with the upload step

Related to: #3844

doc/source/conf.py

@@ -19,6 +19,7 @@
 from docutils.parsers.rst import Directive
 from docutils import nodes
 from sphinx import addnodes
+from sphinx.util import logging
 import shutil
 
 # <-----------------Override the sphinx pdf builder---------------->
@@ -40,6 +41,12 @@ def visit_desc_content(self, node: Element) -> None:
 
 # <----------------- End of sphinx pdf builder override---------------->
 
+
+logger = logging.getLogger(__name__)
+
+
+# Sphinx event hooks
+
 class PrettyPrintDirective(Directive):
     """Renders a constant using ``pprint.pformat`` and inserts into the document."""
     required_arguments = 1
@@ -69,10 +76,29 @@ def autodoc_skip_member(app, what, name, obj, skip, options):
     # return True if exclude else None
 
 
+def directory_size(directory_path):
+    """Compute the size (in mega bytes) of a directory."""
+    res = 0
+    for path, _, files in os.walk(directory_path):
+        for f in files:
+            fp = os.path.join(path, f)
+            res += os.stat(fp).st_size
+    # Convert in mega bytes
+    res /= 1e6
+    return res
+
 def remove_doctree(app, exception):
-    """Remove the .doctree directory created during the documentation build.
-    """
-    shutil.rmtree(app.doctreedir)
+    """Remove the .doctree directory created during the documentation build."""
+
+    # Keep the doctree to avoid creating it twice. This is typically helpful in CI/CD
+    # where we want to build both HTML and PDF pages.
+    if bool(int(os.getenv("SPHINXBUILD_KEEP_DOCTREEDIR", "0"))):
+        logger.info(f"Keeping directory {app.doctreedir}.")
+    else:
+        size = directory_size(app.doctreedir)
+        logger.info(f"Removing doctree {app.doctreedir} ({size} MB).")
+        shutil.rmtree(app.doctreedir, ignore_errors=True)
+        logger.info(f"Doctree removed.")
 
 
 def setup(app):
@@ -324,7 +350,6 @@ def setup(app):
         "api_key": os.getenv("MEILISEARCH_PUBLIC_API_KEY", ""),
         "index_uids": {
             f"pyaedt-v{get_version_match(__version__).replace('.', '-')}": "PyAEDT",
-            f"pyedb-v{get_version_match(__version__).replace('.', '-')}": "EDB API",
         },
     },
 }