Make cuda args to be None by default and add function to retrive cuda version from .bazelrc

Author: nitins17

build/build.py

@@ -73,7 +73,7 @@ def add_cuda_version_argument(parser: argparse.ArgumentParser):
   parser.add_argument(
       "--cuda_version",
       type=str,
-      default="12.3.2",
+      default=None,
       help="Hermetic CUDA version to use",
   )
 
@@ -82,7 +82,7 @@ def add_cudnn_version_argument(parser: argparse.ArgumentParser):
   parser.add_argument(
       "--cudnn_version",
       type=str,
-      default="9.1.1",
+      default=None,
       help="Hermetic cuDNN version to use",
   )
 
@@ -577,7 +577,10 @@ async def main():
 
   if "cuda" in args.command:
     bazel_command.append("--enable-cuda=True")
-    cuda_major_version = args.cuda_version.split(".")[0]
+    if args.cuda_version:
+      cuda_major_version = args.cuda_version.split(".")[0]
+    else:
+      cuda_major_version = utils.get_cuda_major_version()
     bazel_command.append(f"--platform_version={cuda_major_version}")
 
   if "rocm" in args.command:

build/tools/utils.py

@@ -192,6 +192,16 @@ def get_clang_path_or_exit():
     )
     sys.exit(-1)
 
+def get_cuda_major_version():
+  """Extract the CUDA major version from the .bazelrc"""
+  with open(".bazelrc", "r") as f:
+    for line in f:
+      match = re.search(r'HERMETIC_CUDA_VERSION="([^"]+)"', line)
+      if match:
+        cuda_version=match.group(1)
+        return cuda_version.split(".")[0]
+  return None
+
 
 def get_bazelrc_config(os_name: str, arch: str, artifact: str, request_rbe: bool):
   """Returns the bazelrc config for the given architecture and OS.
@@ -202,8 +212,8 @@ def get_bazelrc_config(os_name: str, arch: str, artifact: str, request_rbe: bool
 
   bazelrc_config = f"{os_name}_{arch}"
 
-  # If a build is requesting RBE, the CLI will use RBE if the host system
-  # supports it, otherwise it will use the "ci_" (non RBE) config.
+  # If a build is requesting RBE, the CLI will use RBE if the host system supports
+  # it, otherwise it will use the "ci_" (non RBE) config.
   if request_rbe:
     if (os_name == "linux" and arch == "x86_64") or (
         os_name == "windows" and arch == "amd64"