[PATCH v4 10/19] tools/docs: sphinx-build-wrapper: add support to run inside venv

[Mauro Carvalho Chehab <mchehab+huawei@xxxxxxxxxx>]

Sometimes, it is desired to run Sphinx from a virtual environment.
Add a command line parameter to automatically build Sphinx from
such environment.

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@xxxxxxxxxx>
---
 tools/docs/sphinx-build-wrapper | 30 +++++++++++++++++++++++++++---
 1 file changed, 27 insertions(+), 3 deletions(-)

diff --git a/tools/docs/sphinx-build-wrapper b/tools/docs/sphinx-build-wrapper
index ea9f8e17b0bc..cf7b30bc40ff 100755
--- a/tools/docs/sphinx-build-wrapper
+++ b/tools/docs/sphinx-build-wrapper
@@ -63,6 +63,7 @@ from jobserver import JobserverExec         # pylint: disable=C0413,C0411,E0401
 #
 #  Some constants
 #
+VENV_DEFAULT = "sphinx_latest"
 MIN_PYTHON_VERSION = PythonVersion("3.7").version
 PAPER = ["", "a4", "letter"]
 
@@ -119,8 +120,9 @@ class SphinxBuilder:
 
         return path
 
-    def __init__(self, builddir, verbose=False, n_jobs=None):
+    def __init__(self, builddir, venv=None, verbose=False, n_jobs=None):
         """Initialize internal variables"""
+        self.venv = venv
         self.verbose = None
 
         #
@@ -195,6 +197,21 @@ class SphinxBuilder:
 
         self.env = os.environ.copy()
 
+        #
+        # If venv command line argument is specified, run Sphinx from venv
+        #
+        if venv:
+            bin_dir = os.path.join(venv, "bin")
+            if not os.path.isfile(os.path.join(bin_dir, "activate")):
+                sys.exit(f"Venv {venv} not found.")
+
+            # "activate" virtual env
+            self.env["PATH"] = bin_dir + ":" + self.env["PATH"]
+            self.env["VIRTUAL_ENV"] = venv
+            if "PYTHONHOME" in self.env:
+                del self.env["PYTHONHOME"]
+            print(f"Setting venv to {venv}")
+
     def run_sphinx(self, sphinx_build, build_args, *args, **pwargs):
         """
         Executes sphinx-build using current python3 command and setting
@@ -209,7 +226,10 @@ class SphinxBuilder:
 
             cmd = []
 
-            cmd.append(sys.executable)
+            if self.venv:
+                cmd.append("python")
+            else:
+                cmd.append(sys.executable)
 
             cmd.append(sphinx_build)
 
@@ -533,11 +553,15 @@ def main():
     parser.add_argument('-j', '--jobs', type=jobs_type,
                         help="Sets number of jobs to use with sphinx-build")
 
+    parser.add_argument("-V", "--venv", nargs='?', const=f'{VENV_DEFAULT}',
+                        default=None,
+                        help=f'If used, run Sphinx from a venv dir (default dir: {VENV_DEFAULT})')
+
     args = parser.parse_args()
 
     PythonVersion.check_python(MIN_PYTHON_VERSION)
 
-    builder = SphinxBuilder(builddir=args.builddir,
+    builder = SphinxBuilder(builddir=args.builddir, venv=args.venv,
                             verbose=args.verbose, n_jobs=args.jobs)
 
     builder.build(args.target, sphinxdirs=args.sphinxdirs, conf=args.conf,
-- 
2.51.0