[PATCH v5 09/18] 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 | 32 +++++++++++++++++++++++++++++---
 1 file changed, 29 insertions(+), 3 deletions(-)

diff --git a/tools/docs/sphinx-build-wrapper b/tools/docs/sphinx-build-wrapper
index 9e17c0dbaccd..b34389f65076 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"]
 
@@ -172,8 +173,9 @@ class SphinxBuilder:
         if not verbose:
             self.sphinxopts += ["-q"]
 
-    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
 
         #
@@ -219,6 +221,21 @@ class SphinxBuilder:
 
         self.get_sphinx_extra_opts(n_jobs)
 
+        #
+        # 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.
@@ -253,7 +270,12 @@ class SphinxBuilder:
             if self.n_jobs:
                 n_jobs = str(self.n_jobs)
 
-            cmd = [sys.executable, sphinx_build]
+            if self.venv:
+                cmd = ["python"]
+            else:
+                cmd = [sys.executable,]
+
+            cmd += [sphinx_build]
             cmd += [f"-j{n_jobs}"]
             cmd += self.sphinxopts
             cmd += build_args
@@ -562,11 +584,15 @@ 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